iptables command HowTo - Linux / Unix Q & A from nixCraft

How to use or specify multiple IP addresses in iptables source or destination on Linux

in CentOS, Debian / Ubuntu, Iptables, Linux, RedHat and Friends, Suse last updated June 29, 2017

I need to specific multiple IP address in iptables using Linux script. How do I create a rule that uses multiple source or destination IP addresses ?

Linux Iptables Delete postrouting Rule Command

in CentOS, Debian / Ubuntu, Iptables, Linux, RedHat and Friends, Suse last updated June 28, 2016

I am a new Linux server sysadmin. I need to delete POSTROUTING rule. How do I delete postrouting rule on Linux server?

How to list all iptables rules with line numbers on Linux

in CentOS, Debian / Ubuntu, Iptables, Linux, RedHat and Friends, Suse last updated January 22, 2018

I recently added NAT rules on my RHEL 6.x system. How do I see the rules including line numbers that I just added in Linux?

Ubuntu: Stat / Stop / Restart Iptables Firewall Service

in Commands, Iptables, Ubuntu Linux last updated May 7, 2015

I am a new Ubuntu Linux version 12.04 LTS user. How do I stop or start iptables based firewall service on Ubuntu Linux using bash command line options?

Nginx: Block URL Access (wp-admin/wp-login.php) To All Except One IP Address

in Linux, Nginx, Security, UNIX, Wordpress last updated April 14, 2013

I am the small business owner and runs my own web-site. I have noticed increased cracking activity against by blog. What’s the best way to block WordPress URLs such as example.com/blog/wp-login.php and example.com/blog/wp-admin/ in the nginx web-server?

Linux: Iptables List and Show All NAT IPTables Rules Command

in CentOS, Debian / Ubuntu, Iptables, Linux, Suse last updated August 17, 2017

I am using /sbin/iptables -L -v -n | more command. However, I am unable to list NAT rules. How do I use the iptables command to view or list NAT rules stored in NAT tables? How do I see all the rules in NAT tables under CentOS / RHEL / Debian / Ubuntu Linux based server?

Linux Iptables Setup Firewall For a Web Server

in CentOS, Iptables, RedHat and Friends, Security last updated January 15, 2013

I have setup an Apache web server on CentOS Linux. How do I configure firewall to allow or block access? How do I setup firewall for a web server under RHEL or CentOS Linux v6.x?