Guy Rutenberg » iptables http://www.guyrutenberg.com Keeping track of what I do Sat, 14 Jan 2012 11:30:25 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Iptables Cheatsheet http://www.guyrutenberg.com/2009/02/26/iptables-cheatsheet/ http://www.guyrutenberg.com/2009/02/26/iptables-cheatsheet/#comments Thu, 26 Feb 2009 06:19:47 +0000 Guy http://www.guyrutenberg.com/?p=273 From time to time I find myself having to go through man pages and googling for some simple iptable rules. This post is meant as a cheatsheet for me, so I can concentrate here various rules and remarks.

I hope others will benefit from this cheatsheet as well. Intend to expand it over time as I gather more rules and tips, so bookmarking the post might be a good idea. Last but not least, if you have some useful iptables rules I’ve missed please send them using the comments.

Blocking specific IPs

iptables -I INPUT -s "207.58.140.12" -j DROP

Blocking a range of IPs (IP block)

iptables -I INPUT -s "207.58.140.0/24" -j DROP

The number after the slash (/) determines the number of bits (starting with the most significant one) considered when matching an IP address. For example the above rule will block any packets from 207.58.140.* . Other useful number of bits are 16 (for matching the first two octets) and 8 (only the first octet).

Deleting rules

Just specify the rule after a -D flag. E.g.

iptables -D INPUT -s "207.58.140.12" -j DROP

Saving new rules

/etc/init.d/iptables save
]]> http://www.guyrutenberg.com/2009/02/26/iptables-cheatsheet/feed/ 0