How to Install Snort and Usage in Ubuntu 15.04

August 10, 2015 | By in NETWORK, SECURITY
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Intrusion detection in a network is important for IT security. Intrusion Detection System used for the detection  of illegal and malicious attempts in the network. Snort is well-known  open source intrusion detection system. Web interface (Snorby) can be used  for better analysis of alerts.  Snort can be used as an intrusion prevention system with iptables/pf firewall.  In this article, we will install and configure an open source IDS system snort.

Snort Installation


Data Acquisition library (DAQ) is used by the snort for abstract calls to packet capture libraries.  It is available on snort website.  Downloading process is shown in the following screenshot.


Extract it and run ./configure, make and make install commands for DAQ installation.  However, DAQ required other tools therefore ./configure script will generate following errors .

flex and bison error


libpcap error.

libpcap error

Therefore first install flex/bison and libcap before DAQ installation which is shown in the figure.


Installation of libpcap development library is shown below

libpcap-dev installation

After installation of necessary tools, again run ./configure script which will show following output.


make and make install commands result is shown in the following screens.

make install


After successful installation of DAQ, now we will install snort.   Downloading using wget is shown in the below figure.


Extract compressed package using  below given command.

#tar -xvzf  snort-


Create installation directory and set prefix parameter in the configure script. It is also recommended to enable sourcefire flag for Packet Performance Monitoring (PPM).

#mkdir /usr/local/snort

#./configure --prefix=/usr/local/snort/ --enable-sourcefire


Configure script generates error due to missing libpcre-dev , libdumbnet-dev and zlib development libraries.

error due to missing libpcre library.


error due to missing dnet (libdumbnet) library.

libdnt error

configure script generate error due to missing zlib library.

zlib error

Installation of all required development libraries is shown in the next screenshots.

 # aptitude install libpcre3-dev

libpcre3-dev install

# aptitude install libdumbnet-dev

libdumnet-dev installation

# aptitude install zlib1g-dev

zlibg-dev installation

After installation of above required libraries for snort, again run the configure scripts without any error.

Run make & make install commands for the  compilation and installations of snort in /usr/local/snort directory.


make snort

#make install

make install snort

Finally snort running from /usr/local/snort/bin directory.  Currently it is in promisc mode (packet dump mode) of all traffic on eth0 interface.

snort running

Traffic  dump by the snort interface is shown  in following figure.


Rules and Configuration of Snort

Snort installation from source code required rules and configuration setting therefore now we will copy rules and configuration under /etc/snort directory. We have created single bash scripts for rules and configuration setting. It is used for following snort setting.

  • Creation of snort user for snort IDS service on linux.
  • Creation of directories and files under /etc directory for snort configuration.
  • Permission setting and copying data from etc directory of snort source code.
  • Remove # (comment sign) from rules path in snort.conf file.
#!/bin/bash##PATH of source code of snort
echo "adding group and user for snort..."
groupadd snort &> /dev/null
useradd snort -r -s /sbin/nologin -d /var/log/snort -c snort_idps -g snort &> /dev/null#snort configuration
echo "Configuring snort..."mkdir -p /etc/snort
mkdir -p /etc/snort/rules
touch /etc/snort/rules/black_list.rules
touch /etc/snort/rules/white_list.rules
touch /etc/snort/rules/local.rules
mkdir /etc/snort/preproc_rules
mkdir /var/log/snort
mkdir -p /usr/local/lib/snort_dynamicrules
chmod -R 775 /etc/snort
chmod -R 775 /var/log/snort
chmod -R 775 /usr/local/lib/snort_dynamicrules
chown -R snort:snort /etc/snort
chown -R snort:snort /var/log/snort
chown -R snort:snort /usr/local/lib/snort_dynamicrules
###copy  configuration and rules from  etc directory under source code of snort
echo "copying from snort source to /etc/snort ....."
echo $snort_src
echo "-------------"
cp $snort_src/etc/*.conf* /etc/snort
cp $snort_src/etc/*.map /etc/snort##enable rules
sed -i 's/include \$RULE\_PATH/#include \$RULE\_PATH/' /etc/snort/snort.conf
echo "---DONE---"
Change the snort source directory in the script and run it.  Following output appear in case of success.
running script
 Above script copied following files/directories from snort source into /etc/snort configuration file.
files copied
Snort configuration file is very complex however following necessary changes are required in snort.conf for IDS proper working.
ipvar HOME_NET  # LAN side
ipvar EXTERNAL_NET !$HOME_NET   # WAN side
veriable set
var RULE_PATH /etc/snort/rules     # snort signature path
var SO_RULE_PATH /etc/snort/so_rules        #rules in shared libraries
var PREPROC_RULE_PATH /etc/snort/preproc_rules  # Preproces path
var WHITE_LIST_PATH /etc/snort/rules        # dont scan
var BLACK_LIST_PATH /etc/snort/rules        #  Must scan
main path
include $RULE_PATH/local.rules   # file for custom rules
remove comment sign (#) from other rules such as ftp.rules,exploit.rules etc.
 path rules
Now Download community rules  and extract under /etc/snort/rules directory. Enable community and emerging threats  rules  in snort.conf file.
community rules
 Run following command to test the configuration file after above mentioned changes.
#snort -T -c /etc/snort/snort.conf
snort running


In this article our focus was on the installation and configuration of an open source IDPS system snort on Ubuntu distribution. By default it is used for the monitoring of events however it can con configured inline mode for the protection of network. Snort rules can be tested and analysed in offline mode using pcap capture file.


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