CSF Installation Guide Over Several Linux Distributions | Security | Linux Administration

Installation Guide – CSF

Config Server Firewall, widely known as CSF is used to enhance the security of server’s or system’s running over various Linux distributions (generic Linux OS). CSF can be installed over Linux based Plain machines, VPS or Servers. It also provides preconfigured configurations and control panel UI’s for cPanel, DirectAdmin, and Webmin.

Let’s begin with installation folks.

Installation Commands

cd /usr/src

wget https://download.configserver.com/csf.tgz

tar -xzf csf.tgz

cd csf

sh install.sh

Test whether you have the required iptables modules:

perl /usr/local/csf/bin/csftest.pl

Configuring CSF

Edit file /etc/csf/csf.conf to configure CSF

Vim /etc/csf/csf.conf

Enabling CSF from Testing to Production Mode, by changing 1 to 0.

TESTING = "0"

Allowing Basic Ports through CSF

TCP_IN = "20,21,22,25,53,80,110,143,443,465,587,993,995"

TCP_OUT = "20,21,22,25,53,80,110,113,443"

UDP_IN = "20,21,53"

UDP_OUT = "20,21,53,113,123"

Apply the changes by Restarting CSF Firewall.

csf -r

Especially, CSF offers a wide range of other settings which are not listed in this tutorial. The default settings offered are generally good and can be used on almost any server. CSF offers prevention from several types of attacks which almost includes:

Login Tracking, Process Tracking, Directory Watching, Advanced Allow/Deny Filters, Block Reporting, Port Flood Protection, External Pre- and Post- Scripts, Port Knocking, Connection Limit Protection, Port/IP address Redirection, IP Block Lists, Exim SMTP AUTH Restriction.

Detailed instructions about the usage of these services can be read from CSF official documentation.

Useful CLI Commands For CSF

• Start the firewall

csf -s

• Flush/Stop firewall

csf -f

• Restart the firewall

csf -r

• Allow an IP and add to /etc/csf/csf.allow

csf -tr 192.168.0.1

• Remove an IP from temporarily allow list

csf -tr 192.168.0.1

• Flush all IPs from the temporarily allow list

csf -tf 192.168.0.1

• Deny an IP and add to /etc/csf/csf.deny

csf -d

• Unblock an IP and remove from /etc/csf/csf.deny

csf -dr 192.168.0.1

• Remove and unblock all entries in /etc/csf/csf.deny

csf -df 192.168.0.1

Finally, we are coming to an end. Hope this tutorial would be “AS STRAIGHT AS ARROW” for you all. Kindly support & share if you find this tutorial helpful.