iptable rule

vinaytp · 10-26-2009, 01:25 AM

Hi all..

Can anyone please tell me in the below rule

Code:

-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT

-m state --state NEW -m tcp

part stands for ?? confused....I understood remaining stuff

Thanks in advance....

btmiller · 10-26-2009, 01:39 AM

Check the iptables man page. Essentially -m state tells iptables to use the state matching module (likewise -m tcp tells it to use the TCP module). The --state NEW is an argument to the state matching module, which tells it to match NEW packets (i.e. SYN packets which are not part of an established connection -- I think this will only match SYN packets and not SYN/ACK packets). Essentially, this rule tells iptables to allow incoming new connections to port 22.