Re: iptables & tcp wrappers

Whelan, Paul wrote:
> "iptables -L --line-numbers" will show you the line numbers of the
> rules.
> "iptables -A INPUT -p tcp -s ! ONLY_IP_YOU_WANT --dport 22 -j DROP" will
> block every connection to port 22 except ONLY_IP_YOU_WANT.

not really... a good firewall (IMHO) drops everything, rejects auth 
(nasty timeouts on ftp, irc, ... if you just drop auth), and accepts 
these 4(or 5) icmp requests:
"source-quench"
"parameter-problem"
"time-exceeded"
"destination-unreachable"
and your clients probably want the "echo-request" too :)

if you start like this, you can just use:
"iptables -A INPUT -p tcp -s <IP_YOU WANT TO ALLOW> --dport 22 --syn -m 
state --state NEW -j ACCEPT"

and off course, you will need this rule too:
"iptables -A INPUT  -m state --state RELATED,ESTABLISHED -j ACCEPT"
(keeps your network a little bit cleaner)

-- 
harry
aka Rik Bobbaers

K.U.Leuven - LUDIT             -=- Tel: +32 485 52 71 50
[email protected] -=- http://harry.ulyssis.org

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