Hack The Sec-Leading Resource Of Linux Tutorial: Iptables

Allow/deny,disable or drop/block ping packets on Linux serves

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<span style="color: #990000; font-family: "verdana" , "geneva" , sans-serif; font-size: large;"><span style="line-height: 26px;"><b><u>Allow/deny,disable or drop/block ping request</u></b></span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Ping is a computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network, and to measure the round-trip time for messages sent from the originating host to a destination computer and echoed back to the source. </span></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMkvanWwL3sQ5vslmP9RJn-wN23GzG7XOupgaiHDMQJzpuqMvvq8LlJAZ6Q0fGyREUOXoCHIEyBnFXFWJFq0YlnOGnfGnZmTFBoPHoDn4etpw8Fi6u-G95vqTG-_KDlTEvCd2xtpZxzRHE/s1600/security.jpg" imageanchor="1" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMkvanWwL3sQ5vslmP9RJn-wN23GzG7XOupgaiHDMQJzpuqMvvq8LlJAZ6Q0fGyREUOXoCHIEyBnFXFWJFq0YlnOGnfGnZmTFBoPHoDn4etpw8Fi6u-G95vqTG-_KDlTEvCd2xtpZxzRHE/s1600/security.jpg" /></a></div>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">The name comes from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects under water,although it is sometimes interpreted as a backronym to packet Internet groper</span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Blocking PING on server is helpful sometimes, if the server is continue to face any type of DDoS attack by using the PING feature. By using <a href="http://www.hackthesec.co.in/search/label/Iptables" target="_blank">iptables </a>we can simply stop the PING option.</span></span><br />
<span style="color: #0b5394; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>STEP : 1</u></b></span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">You can setup kernel variable to drop all ping packets. Type the following command at shell prompt:</span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">This instructs the kernel to simply ignore all ping requests.</span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">To enable ping request type the command:</span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">echo "0" > /proc/sys/net/ipv4/icmp_echo_ignore_all</span></span></pre>
<span style="font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><span style="color: #333333;">You can add following line to</span><b><span style="color: #990000;"> /etc/sysctl.conf</span></b><span style="color: #333333;"> file:</span></span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;"># vi /etc/sysctl.conf </span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Append following line:</span></span><br />
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;">net.ipv4.icmp_echo_ignore_all = 1</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Save and close the file.</span></span><br />
<span style="color: #0b5394; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>STEP : 2</u></b></span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Also we can manage it by the help of '<a href="http://www.hackthesec.co.in/search/label/Iptables" target="_blank">iptables</a>'. The 'ping' is using ICMP to communicate. We can simply manage the 'icmp : Internet Controlled Message Protocol'from iptables.</span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">The below pasted switches are required for creating a rule for managing icmp.</span></span><br />
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;">-A : Add a rule
-D : Delete rule from table
-p : To specify protocol (here 'icmp')
--icmp-type : For specifying type
-J : Jump to target</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Normally using icmp types and its Codes Click here for ICMP Types and Codes</span></span><br />
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;">echo-request   :  8
echo-reply     :  0</span><span style="line-height: 25.7143px; white-space: normal;">
</span></span></pre>
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<span style="color: #0b5394; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;"><b><u>How to block PING to your server with an error message?</u></b></span></span></div>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">In this way you can partially block the PING with an error message 'Destination Port Unreachable'. Add the following iptables rules to block the PING with an error message. (Use REJECT as Jump to target)</span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A INPUT -p icmp --icmp-type echo-request -j REJECT</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Result : - </span></span><br />
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;">[root@redhat ~]# ping hackthesec.co.in
Pinging hackthesec.co.in [216.239.34.21] with 32 bytes of data:
From 216.239.34.2 icmp_seq=1 Destination Port Unreachable
From 216.239.34.2 icmp_seq=2 Destination Port Unreachable
From 216.239.34.2 icmp_seq=3 Destination Port Unreachable</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b>To block without any messages use DROP as Jump to target.</b></span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A INPUT -p icmp --icmp-type echo-request -j DROP
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j DROP</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b>Allow Ping from Outside to Inside</b></span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT</span></span></pre>
<span style="color: #0b5394; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>How to block PING from your server?</u></b></span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">In this way you can block PING option from your server to outside. Add these rules to your iptables to do the same.</span></span><br />
<br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Block PING operation with message 'Operation not permitted'</span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A OUTPUT -p icmp --icmp-type echo-request -j DROP</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">Result:-</span></span><br />
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><span style="color: #333333; font-family: "menlo" , "monaco" , "consolas" , "courier new" , monospace; font-size: medium;"><span style="line-height: 25.7143px;">root@test [~]# ping google.com
PING google.com (173.194.34.136) 56(84) bytes of data.
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted
ping: sendmsg: Operation not permitted</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>To block with out any error messages</u></b></span></span><br />
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">For this, DROP the echo-reply to the INPUT chain of your iptables.</span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A OUTPUT -p icmp --icmp-type echo-request -j DROP
iptables -A INPUT -p icmp --icmp-type echo-reply -j DROP</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>Allow Ping from Inside to Outside</u></b></span></span><br />
<pre style="background-attachment: initial; background-clip: initial; background-color: #363636; background-image: initial; background-origin: initial; background-position: initial; background-repeat: initial; background-size: initial; border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="color: white; font-family: "monaco" , "courier new" , "dejavu sans mono" , "bitstream vera sans mono" , monospace;"><span style="font-size: 15px; line-height: 19px; white-space: pre-wrap;">iptables -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT</span></span></pre>
<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;">You can use the icmp code instead of icmp-type name for adding rule to iptables.</span></span><br />
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<span style="color: #333333; font-family: "verdana" , "geneva" , sans-serif;"><span style="font-size: 15px; line-height: 26px;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></span></span></div>

Allow/deny,disable or drop/block ping packets on Linux serves

Allow/deny,disable or drop/block ping request Ping is a computer network administration software utility used to test the reachability of ...

How to Block abusive IP addresses using IPTABLES Firewall in Debian/Ubuntu

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<h1 class="entry-title" style="background-color: white; box-sizing: border-box; font-family: Lato, sans-serif; line-height: 1.1; margin: 20px 0px 10px;">
<span style="color: #990000; font-size: large;"><u>Blocking abusive IP addresses using IPTABLES Firewall</u></span></h1>
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<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">In computing, a firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed to not be secure or trusted. </span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVLpw76eQcyxf_FJfA5z-xQ_rnjxqJKvLr9bioRWOZ81yGF0gkvnv0ZmEtr_cz0GqKBerizxuLX9yKohg0XrJiIrpt3n3evDA2WOxvLVHWD3uPwxo6i3pImzS__HETrwaS2C9lFrontj46/s1600/firewall_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVLpw76eQcyxf_FJfA5z-xQ_rnjxqJKvLr9bioRWOZ81yGF0gkvnv0ZmEtr_cz0GqKBerizxuLX9yKohg0XrJiIrpt3n3evDA2WOxvLVHWD3uPwxo6i3pImzS__HETrwaS2C9lFrontj46/s1600/firewall_www.hackthesec.co.in.jpg" /></a></div>
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<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><br /></span></span></div>
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<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">Firewalls are often categorized as either network firewalls or host-based firewalls. Network firewalls are a software appliance running on general purpose hardware or hardware-based firewall computer appliances that filter traffic between two or more networks. Host-based firewalls provide a layer of software on one host that controls network traffic in and out of that single machine</span></span></div>
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<div style="font-family: verdana, geneva, sans-serif;">
<ul style="color: #222222; font-size: 15px; line-height: 26px; text-align: left;">
<li>Flushing the old firewall rules</li>
<li>Determining service ports</li>
<li>Setting-up default policies</li>
<li>Setting-up your firewall rules</li>
<li>Saving your firewall rules</li>
</ul>
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<span style="font-size: 15px; line-height: 26px;"><b><u><span style="color: #0b5394;">BLOCKING IPs USING IPTABLES</span></u></b></span></div>
<div style="color: #222222;">
<span style="font-size: 15px; line-height: 26px;">To block some abusive IP address or range of IPs, you can use the following iptables rules:</span></div>
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<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: trebuchet ms, sans-serif;"><span style="font-size: 15px; line-height: 15.6px;">## iptables -I INPUT -s 1.2.3.4 -j DROP
## iptables -I INPUT -s 1.2.0.0/16 -j DROP</span></span></pre>
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<span style="color: #0b5394; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;"><b><u>CREATING THE BLACKLIST</u></b></span></span></div>
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<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">For better readability and maintenance, it is a good idea to have all abusing IPs in one particular file, for example <b>/etc/blacklist.ips</b>. This way, you can add the IP addresses or subnets in this file (one IP or subnet per line) and use the <b>fwall-rules</b> script below to block anything listed in this file.</span></span></div>
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<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">So, create or edit <b>/usr/local/bin/fwall-rules </b>and make it as follows:</span></span></div>
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<div style="color: #222222; font-family: verdana, geneva, sans-serif;">
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;">#!/bin/bash
#
# iptables firewall script
# 
#

IPTABLES=/sbin/iptables
BLACKLIST=/etc/blacklist.ips

echo " * flushing old rules"
${IPTABLES} --flush
${IPTABLES} --delete-chain
${IPTABLES} --table nat --flush
${IPTABLES} --table nat --delete-chain

echo " * setting default policies"
${IPTABLES} -P INPUT DROP
${IPTABLES} -P FORWARD DROP
${IPTABLES} -P OUTPUT ACCEPT

echo " * allowing loopback devices"
${IPTABLES} -A INPUT -i lo -j ACCEPT
${IPTABLES} -A OUTPUT -o lo -j ACCEPT

${IPTABLES} -A INPUT -p tcp ! --syn -m state --state NEW -j DROP
${IPTABLES} -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

## BLOCK ABUSING IPs HERE ##
#echo " * BLACKLIST"
#${IPTABLES} -A INPUT -s _ABUSIVE_IP_ -j DROP
#${IPTABLES} -A INPUT -s _ABUSIVE_IP2_ -j DROP

echo " * allowing ssh on port 5622"
${IPTABLES} -A INPUT -p tcp --dport 5622  -m state --state NEW -j ACCEPT

echo " * allowing ftp on port 21"
${IPTABLES} -A INPUT -p tcp --dport 21  -m state --state NEW -j ACCEPT

echo " * allowing dns on port 53 udp"
${IPTABLES} -A INPUT -p udp -m udp --dport 53 -j ACCEPT

echo " * allowing dns on port 53 tcp"
${IPTABLES} -A INPUT -p tcp -m tcp --dport 53 -j ACCEPT

echo " * allowing http on port 80"
${IPTABLES} -A INPUT -p tcp --dport 80  -m state --state NEW -j ACCEPT

echo " * allowing https on port 443"
${IPTABLES} -A INPUT -p tcp --dport 443 -m state --state NEW -j ACCEPT

echo " * allowing smtp on port 25"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT

echo " * allowing submission on port 587"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 587 -j ACCEPT

echo " * allowing imaps on port 993"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 993 -j ACCEPT

echo " * allowing pop3s on port 995"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 995 -j ACCEPT

echo " * allowing imap on port 143"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 143 -j ACCEPT

echo " * allowing pop3 on port 110"
${IPTABLES} -A INPUT -p tcp -m state --state NEW -m tcp --dport 110 -j ACCEPT

echo " * allowing ping responses"
${IPTABLES} -A INPUT -p ICMP --icmp-type 8 -j ACCEPT

# DROP everything else and Log it
${IPTABLES} -A INPUT -j LOG
${IPTABLES} -A INPUT -j DROP

#
# Block abusing IPs 
# from ${BLACKLIST}
#
if [[ -f "${BLACKLIST}" ]] && [[ -s "${BLACKLIST}" ]]; then
    echo " * BLOCKING ABUSIVE IPs"
    while read IP; do
        ${IPTABLES} -I INPUT -s "${IP}" -j DROP
    done < <(cat "${BLACKLIST}")
fi

#
# Save settings
#
echo " * SAVING RULES"

if [[ -d /etc/network/if-pre-up.d ]]; then
    if [[ ! -f /etc/network/if-pre-up.d/iptables ]]; then
        echo -e "#!/bin/bash" > /etc/network/if-pre-up.d/iptables
        echo -e "test -e /etc/iptables.rules && iptables-restore -c /etc/iptables.rules" >> /etc/network/if-pre-up.d/iptables
        chmod +x /etc/network/if-pre-up.d/iptables
    fi
fi

iptables-save > /etc/fwall.rules
iptables-restore -c /etc/fwall.rules</pre>
</div>
<div>
<span style="color: #222222; font-family: verdana, geneva, sans-serif;"><span style="font-size: 15px; line-height: 26px;">make sure the script is executable by adding an ‘x’ bit to it:</span></span></div>
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-family: trebuchet ms, sans-serif;"><span style="font-size: 15px; line-height: 15.6px;"># chmod +x /usr/local/bin/fwall-rules</span></span></pre>
</div>
<div style="font-family: verdana, geneva, sans-serif;">
<span style="font-size: 15px; line-height: 26px;"><div>
<b><u><span style="color: #0b5394;">APPLYING THE RULES</span></u></b></div>
<div style="color: #222222;">
To apply the firewall rules and block the abusers, you need to just execute the fwall-rules script and that’s it.</div>
</span></div>
<div style="color: #222222; font-family: verdana, geneva, sans-serif;">
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"># fwall-rules
 * flushing old rules
 * setting default policies
 * allowing loopback devices
 * allowing ssh on port 5622
 * allowing ftp on port 21
 * allowing dns on port 53 udp
 * allowing dns on port 53 tcp
 * allowing http on port 80
 * allowing https on port 443
 * allowing smtp on port 25
 * allowing submission on port 587
 * allowing imaps on port 993
 * allowing pop3s on port 995
 * allowing imap on port 143
 * allowing pop3 on port 110
 * allowing ping responses
 * BLOCKING ABUSIVE IPs
 * SAVING RULES</pre>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 13px; line-height: 1.42857; margin-bottom: 10px; overflow: auto; padding: 9.5px; word-break: break-all; word-wrap: break-word;"><a href="http://wwww.hackthesec.co.in/">wwww.hackthesec.co.in</a>
</pre>
</div>
</div>
</div>

How to Block abusive IP addresses using IPTABLES Firewall in Debian/Ubuntu

Blocking abusive IP addresses using IPTABLES Firewall In computing, a firewall is a network security system that monitors and controls t...

How To Install FreePBX on CentOS

<div dir="ltr" style="text-align: left;" trbidi="on">
<h1 class="entry-title" itemprop="headline" style="background-color: #fdfdfd; box-sizing: border-box; font-family: proxima-nova, 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 39px; line-height: 1.1; margin: 21px 0px 0px;">
<u><span style="color: red;">Install FreePBX on CentOS</span></u></h1>
<div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">PBX (stands for private branch exchange) is a private telephone network used that can be very easily connected to the public landline and mobile networks. The PBX network also provides audio, video and instant messaging communication through the TCP/IP protocol stack for its internal network and interconnects its internal network with the Public Switched Telephone Network (PSTN) for telephony communication.</span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggyfE0RGe3F6bNgKJwgmfEIGAcZp-aiPwwHnE7ozF_zlWvKp6oKjpXoSWvr5RXrWcAJ0XpN_TmttG36GOIdt3cSBN8CNZCjuQBl6Xmstji8pMAmlkpIxsB-Pgel9vbFNWYbrxi08fkUEOx/s1600/asterisk_centos_freepbx_www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggyfE0RGe3F6bNgKJwgmfEIGAcZp-aiPwwHnE7ozF_zlWvKp6oKjpXoSWvr5RXrWcAJ0XpN_TmttG36GOIdt3cSBN8CNZCjuQBl6Xmstji8pMAmlkpIxsB-Pgel9vbFNWYbrxi08fkUEOx/s1600/asterisk_centos_freepbx_www.hackthesec.co.in.png" /></a></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;"><br /></span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">A lot of successful businesses are aiming to have their own telephony system that will allow them to have many different features, lower their costs using VoIP, especially on international calls, but inside that company as well. Some of them are choosing hosted solution, some are having their own In-House solution. In this tutorial we are installing FreePBX & Asterisk VoIP on a base <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">CentOS</a> 6.4 installation.</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Asterisk is an open source software implementation of a telephone private branch exchange (PBX); it was created in 1999. Like any PBX, it allows attached telephones to make calls to one another, and to connect to other telephone services, such as the public switched telephone network (PSTN) and Voice over Internet Protocol (VoIP) services. Its name comes from the asterisk symbol, *. Asterisk includes many features like Voice mail, conference calling, Interactive voice response, automatic call distribution, Fax to email services etc.</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">In order to control Asterisk, we will use FreePBX. It is open source graphical user interface that makes asterisk management very easy. It is usually included in the asterisk distribution, but it can be installed manually if needed. FreePBX distribution is unified server distribution that includes all of the software packages and dependencies required for Asterisk VoIP server, such as:</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; margin-bottom: 10.5px;">
</div>
<ul style="text-align: left;">
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/Apache" target="_blank">Apache Web Server</a></span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Cyrus SASL (Simple Authentication Security Layer)</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Dnsmasq</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/fail2ban" target="_blank">Fail2ban</a></span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/Iptables" target="_blank">iptables</a></span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Mailx</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/Mysql" target="_blank">MySQL </a>Server</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Network Time Protocol</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/VPN" target="_blank">OpenVPN </a>Server</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;"><a href="http://www.hackthesec.co.in/search/label/postfix" target="_blank">Postfix </a>MTA</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Prosody XMPP Server</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">TFTP Server</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Very Secure FTP Daemon (<a href="http://www.hackthesec.co.in/search/label/vsftp" target="_blank">vsftpd</a>)</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Vim text editor</span></li>
</ul>
<br />
<div style="background-color: #fdfdfd; box-sizing: border-box; margin-bottom: 10.5px;">
</div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Before we start with the installation, we must make sure that the server has decent and stable internet connection and it should be in a geographical location near the place where the majority of our calls will come from. We also need to determine the size of our server. That will depends mostly on the number of the concurrent calls that we anticipate to have. It is not that bad even if we choose wrong, since we can resize our server at any time later, but some best practices showed that we should follow this calculations.</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; margin-bottom: 10.5px;">
</div>
<ul style="text-align: left;">
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 512 MB RAM can support approximately 5-15 concurrent calls</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 1 GB can support approximately 15-25 concurrent calls</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 2 GB can support approximately 25-50 concurrent calls</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 4 GB can support approximately 50-100 concurrent calls</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 8 GB can support approximately 100-175 concurrent calls</span></li>
<li><span style="font-family: Georgia, 'Times New Roman', serif; font-size: 18px; line-height: 28px;">Server with 16 GB can support approximately 175+ concurrent calls</span></li>
</ul>
<br />
<div style="background-color: #fdfdfd; box-sizing: border-box; margin-bottom: 10.5px;">
</div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Next, we must make sure that our fully qualified domain name is properly set in our hosts file and make sure that the server time setting match the appropriate time zone that server belongs to. The last step before we actually start with the installation is to update our currently installed packages from the standard <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">CentOS </a>repositories:</span></div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 14px; line-height: 1.42857; margin-bottom: 10.5px; overflow: auto; padding: 10px; word-break: break-all; word-wrap: break-word;"><code style="background-color: transparent; border-radius: 0px; box-sizing: border-box; color: inherit; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: inherit; padding: 0px; white-space: pre-wrap;"># yum update
</code></pre>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Now, we are ready to start the deployment. We will use installation script that we need to download. The script will download some file during the installation, so we will use <code style="background-color: #f9f2f4; border-radius: 4px; box-sizing: border-box; font-size: 16.2px; padding: 2px 4px;">/tmp</code> folder during the installations.</span></div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 14px; line-height: 1.42857; margin-bottom: 10.5px; overflow: auto; padding: 10px; word-break: break-all; word-wrap: break-word;"><code style="background-color: transparent; border-radius: 0px; box-sizing: border-box; color: inherit; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: inherit; padding: 0px; white-space: pre-wrap;"># cd /tmp
# wget http://upgrades.freepbxdistro.org/blank-centos-installer/5.211.65-track/5.211.65-1-Installer-Script.sh
# /tmp/4.211.64-1-Installer-Script.sh
</code></pre>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Once it is finished, we will have fully functional IP-PBX server, based on the FreePBX Distribution. Now, we need to test if our GUI works. To do that, we will open our browser and point to the fully qualified name or the IP of our newly installed PBX, we will be presented with FreePBX administrator-account setup screen. We should setup our admin account using the GUI. That will be the information that we will use later for managing the server through the GUI.</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">If we want to upgrade out FreePBX system later, we can search for available upgrades, download the upgrade script and execute it, similar to the installation process. First, we need to determine which our current version is:</span></div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 14px; line-height: 1.42857; margin-bottom: 10.5px; overflow: auto; padding: 10px; word-break: break-all; word-wrap: break-word;"><code style="background-color: transparent; border-radius: 0px; box-sizing: border-box; color: inherit; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: inherit; padding: 0px; white-space: pre-wrap;"># cat /etc/schmooze/pbx-version
</code></pre>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">Then, we can check the change list for the new version that is available and make decision whether we would like to upgrade or not. The upgrade process work same as the installation. The upgrade script might ask us for some additional information or confirmation. Once the upgrade is done we can check and confirm that our system is upgraded but executing:</span></div>
<pre style="background-color: whitesmoke; border-radius: 4px; border: 1px solid rgb(204, 204, 204); box-sizing: border-box; color: #333333; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: 14px; line-height: 1.42857; margin-bottom: 10.5px; overflow: auto; padding: 10px; word-break: break-all; word-wrap: break-word;"><code style="background-color: transparent; border-radius: 0px; box-sizing: border-box; color: inherit; font-family: Menlo, Monaco, Consolas, 'Courier New', monospace; font-size: inherit; padding: 0px; white-space: pre-wrap;"># cat /etc/schmooze/pbx-version
</code></pre>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;">If there is more than one upgrade script available, we should execute every upgrade script, one by one, is sequential order and save every script in the same folder. This Asterisk and OpenPBX server are part of a very wide field and there are a lot of additional things to be considered and explored. However, this tutorial underlines the very basic information and steps that are required in order to get our own PBX system up and running.</span></div>
<div style="background-color: #fdfdfd; box-sizing: border-box; font-size: 18px; line-height: 28px; margin-bottom: 10.5px;">
<span style="font-family: Georgia, Times New Roman, serif;"><a href="http://hackthesec.co.in/" target="_blank">hackthesec.co.in</a><br /><a href="http://hackthesec.co.in/" target="_blank">hackthesec</a></span></div>
</div>
</div>

How To Install FreePBX on CentOS

Install FreePBX on CentOS PBX (stands for private branch exchange) is a private telephone network used that can be very easily connecte...

How to install webmin on centos 6

<div dir="ltr" style="text-align: left;" trbidi="on">
<h1 style="clear: both; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; font-size: 30px; font-weight: normal; height: auto; line-height: 31px; margin: 0px; padding: 0px; text-align: center; width: 614px;">
<span style="color: #990000;"><i><u>Install webmin on centos 6</u></i></span></h1>
<div>
<span style="font-size: large;"><a href="http://www.webmin.com/" rel="nofollow" style="background-color: white; color: #0f4884; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; line-height: 30px; text-decoration: none;" title="Webmin">Webmin</a><span style="background-color: white;"><span style="color: #222222; font-family: Trebuchet, Trebuchet MS, Arial, Verdana, sans-serif;"><span style="line-height: 30px;"> is a web-based interface for system administration for Unix. Using any modern web browser, you can setup user accounts, Apache, DNS, file sharing and much more. Webmin removes the need to manually edit Unix configuration files like /etc/passwd, and lets you manage a system from the console or remotely. See the <a href="http://www.webmin.com/standard.html">standard modules</a> page for a list of all the functions built into Webmin .</span></span></span></span></div>
<div>
<ul style="text-align: left;">
<li><a href="http://www.hackthesec.co.in/2016/01/how-to-install-usermin-on-centos.html" style="background-color: white; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; line-height: 30px;"><span style="color: red; font-size: large;">How to Install Usermin On Linux</span></a></li>
</ul>
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxZ-8UWMA4gXH3-aG3ryEChCYOE8HvILzmgQlPxtnrN71cevQsNmBXwg0NJ6vRaMXAz50q9nqYOglqf6K1GeLq-PTmfjO-beK67zGBvhlxw5PDm-FZ0OB9WziV-1m7z95W4jpNqNCZxKw-/s1600/webmin_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxZ-8UWMA4gXH3-aG3ryEChCYOE8HvILzmgQlPxtnrN71cevQsNmBXwg0NJ6vRaMXAz50q9nqYOglqf6K1GeLq-PTmfjO-beK67zGBvhlxw5PDm-FZ0OB9WziV-1m7z95W4jpNqNCZxKw-/s1600/webmin_www.hackthesec.co.in.jpg" /></a></div>
<div>
<h2 style="background-color: white; clear: both; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; font-size: 24px; font-weight: normal; height: auto; line-height: 28px; margin: 0px; padding: 0px; width: 614px;">
<span style="color: #0b5394;">Webmin installation on centos 6.</span></h2>
<div>
<br /></div>
<div style="background-color: white; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; font-size: 16px; line-height: 30px;">
<strong style="color: #222222;">Step 1 :</strong><span style="color: #222222;"> Create a new file </span><strong><span style="color: red;">webmin.repo</span></strong><span style="color: #222222;"> in </span><strong><span style="color: red;">/etc/yum/repos.d/</span></strong><span style="color: #222222;"> and add the below code.</span></div>
<div style="background-color: white;">
<code style="background-color: #0e0e0e; border-radius: 5px; display: block; padding: 4px;"><code style="border-radius: 5px; display: block; padding: 4px;"><span style="font-family: Verdana, MS Sans Serif, sans-serif, serif;"><span style="font-size: 14px; line-height: 25px;"><span style="color: white;">[</span><span style="color: lime;">Webmin</span><span style="color: white;">]</span></span></span><span style="color: white; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px;">name=Webmin Distribution Neutral</span><span style="color: white; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px;">#baseurl=http://download.webmin.com/download/yum</span></code><code style="border-radius: 5px; display: block; padding: 4px;"><span style="color: white; font-family: Verdana, MS Sans Serif, sans-serif, serif;"><span style="font-size: 14px; line-height: 25px;">mirrorlist=http://download.webmin.com/download/yum/mirrorlist</span></span></code><code style="border-radius: 5px; display: block; padding: 4px;"><span style="color: white; font-family: Verdana, MS Sans Serif, sans-serif, serif;"><span style="font-size: 14px; line-height: 25px;">enabled=1</span></span></code></code><div style="color: #333333; font-family: Trebuchet, 'Trebuchet MS', Arial, Verdana, sans-serif; font-size: 16px; line-height: 30px;">
<span style="color: white;"><br /></span></div>
</div>
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<strong style="color: #222222;">Step 2 :</strong><span style="color: #222222;"> Install webmin GPG key using below command.</span><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">rpm --import http://www.</span><span style="color: lime;">webmin</span><span style="color: white;">.com/jcameron-key.asc</span></code><br /><strong style="color: #222222;">Step 3 :</strong><span style="color: #222222;"> Update the repositories.</span><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">yum </span><span style="color: lime;">check-update</span></code><br /><strong style="color: #222222;">Step 4 :</strong><span style="color: #222222;"> Now install webmin package using yum .</span><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">yum install </span><span style="color: lime;">webmin</span></code><br /><strong style="color: #222222;">Step 5 :</strong><span style="color: #222222;"> Start the service and make it start automatically.</span><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">chkconfig </span><span style="color: lime;">webmin</span><span style="color: white;"> on</span></code><br /><code style="background-color: #0e0e0e; border-radius: 5px; color: white; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;">service webmin start</code><br /><strong style="color: #222222;">Step 6 :</strong><span style="color: #222222;"> By default, Webmin will listen on port 10000, Allow this port in iptables if it is enabled.</span><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">iptables -I INPUT -p tcp --dport </span><span style="color: lime;">10000</span><span style="color: white;"> -j ACCEPT</span></code><br /><code style="background-color: #0e0e0e; border-radius: 5px; display: block; font-family: Verdana, 'MS Sans Serif', sans-serif, serif; font-size: 14px; line-height: 25px; padding: 4px;"><span style="color: white;">service </span><span style="color: lime;">iptables</span><span style="color: white;"> save</span></code><br /><strong style="color: #222222;">Step 7 :</strong><span style="color: #222222;"> Now open </span><span style="color: red;">http://serverip:10000</span><span style="color: #222222;"> in your browser, you could see the below screen after login ( Use root username and password ).</span></div>
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How to install webmin on centos 6

Install webmin on centos 6 Webmin is a web-based interface for system administration for Unix. Using any modern web browser, you can se...

How do I Install and Use Iptables on CentOS/RHEL 7

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<span style="color: #990000;">How do I Install and Use Iptables on CentOS/RHEL 7</span></h2>
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<span style="font-family: "verdana" , sans-serif;"><span style="background-color: white; line-height: 28px;">Latest Linux operating systems like CentOS/RedHat 7 and Fedora 21 has stop using iptables and start now using dynamic firewall daemon firewalld which provides a dynamically managed firewall. It supports for network and zones to assign a level of trust to a network, connections and interfaces. Firewalld also provides and interface for services or applications to add firewall rules directly. This article will help you to disable firewalld service and then install and use iptables on CentOS and Red Hat 7 Systems. </span><a href="https://fedoraproject.org/wiki/FirewallD" style="background-color: white; line-height: 28px; outline: none; text-decoration: none;" target="_blank">Visit here</a><span style="background-color: white; line-height: 28px;"> to read more about firewallD.</span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnwJqO5t-cjYlTKJwDUOWpBE6hpcStrXARypGodCji4qUFUgtg2ocsVUHZGm_VaZJARKMRjmnlgIDhOUHWEO5wTG0-oclNxRCZpvAiHMjuATmAULsaXKwqEUTKSxNrB7g385tyZmzbc_ZT/s1600/firewall_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgnwJqO5t-cjYlTKJwDUOWpBE6hpcStrXARypGodCji4qUFUgtg2ocsVUHZGm_VaZJARKMRjmnlgIDhOUHWEO5wTG0-oclNxRCZpvAiHMjuATmAULsaXKwqEUTKSxNrB7g385tyZmzbc_ZT/s1600/firewall_www.hackthesec.co.in.jpg" /></a></div>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="background-color: white; line-height: 28px;"><br /></span></span></div>
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<span style="color: #0b5394;">Disable Firewalld Service</span></h2>
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<span style="font-family: "verdana" , sans-serif;">Before installing and using iptables services on CentOS and Red Hat 7 systems, we need to disable firewalld service. To completely disable firewalld service use following commands.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"># systemctl <orange style="color: orange;">stop</orange> firewalld
# systemctl <orange style="color: orange;">mask</orange> firewalld<span style="font-size: 0.9em;">
</span></pre>
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<span style="font-family: "verdana" , sans-serif;">Now check firewalld status</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"># <orange style="color: orange;">systemctl status firewalld</orange>

firewalld.service
   Loaded: masked (/dev/null)
   Active: inactive (dead) since Fri 2015-02-27 11:09:37 EST; 56s ago
 Main PID: 7411 (code=exited, status=0/SUCCESS)

Feb 27 11:02:18 svr10 systemd[1]: Started firewalld - dynamic firewall daemon.
Feb 27 11:09:36 svr10 systemd[1]: Stopping firewalld - dynamic firewall daemon...
Feb 27 11:09:37 svr10 systemd[1]: Stopped firewalld - dynamic firewall daemon.<span style="font-size: 0.9em;">
</span></pre>
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<span style="color: #0b5394;">Install Iptables Service in CentOS/RHEL 7</span></h2>
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<span style="font-family: "verdana" , sans-serif;">Now install iptables service using yum package manager using following command.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"># yum install iptables-services -y<span style="font-size: 0.9em;">
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<span style="font-family: "verdana" , sans-serif;">After installing enable iptables service and start using below commands.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"># systemctl <orange style="color: orange;">enable</orange> iptables
# systemctl <orange style="color: orange;">start</orange> iptables<span style="font-size: 0.9em;">
</span></pre>
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<span style="font-family: "verdana" , sans-serif;">Now check the iptables service status using below command.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"># <orange style="color: orange;">systemctl status iptables</orange>

iptables.service - IPv4 firewall with iptables
   Loaded: loaded (/usr/lib/systemd/system/iptables.service; enabled)
   Active: <green style="color: green;">active (exited)</green> since Fri 2015-02-27 11:14:12 EST; 14s ago
  Process: 7938 ExecStart=/usr/libexec/iptables/iptables.init start (code=exited, status=0/SUCCESS)
 Main PID: 7938 (code=exited, status=0/SUCCESS)

Feb 27 11:14:12 svr10 iptables.init[7938]: iptables: Applying firewall rules: [  OK  ]
Feb 27 11:14:12 svr10 systemd[1]: Started IPv4 firewall with iptables.<span style="font-size: 0.9em;">
</span></pre>
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<span style="font-family: "verdana" , sans-serif;">To list iptables rules use following command.</span></div>
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<pre style="-webkit-text-stroke-width: 0px; background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 1.3em; margin: 0px 0px 20px; orphans: auto; outline: 0px; overflow: auto; padding: 20px; text-align: start; text-indent: 0px; text-transform: none; vertical-align: baseline; widows: 1; word-spacing: 0px;"># <orange style="color: orange;">iptables -L</orange>

Chain INPUT (policy ACCEPT)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
ACCEPT     icmp --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere
ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:ssh
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination<span style="font-size: 0.9em;">
</span></pre>
<pre style="-webkit-text-stroke-width: 0px; background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; font-size: 0.9em; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 1.3em; margin: 0px 0px 20px; orphans: auto; outline: 0px; overflow: auto; padding: 20px; text-align: start; text-indent: 0px; text-transform: none; vertical-align: baseline; widows: 1; word-spacing: 0px;"><a href="http://www.hackthesec.co.in/">http://www.hackthesec.co.in</a>
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How do I Install and Use Iptables on CentOS/RHEL 7

How do I Install and Use Iptables on CentOS/RHEL 7 Latest Linux operating systems like CentOS/RedHat 7 and Fedora 21 has stop using ip...