Re: can't ssh outside with OUTPUT (policy ACCEPT)

[Martijn Lievaart <m@rtij.nl>]

Maxim Veksler wrote:
> Hello,
>
> Follwing a recent theread on this list, I've configued my firewall to
> allow incoming traffic from specific IP's only. Now I can't ssh
> outside, could some please explain why this happening ?
>
> The system is redhat 4.
>
> [root@prd-001 ~]# iptables -L
> Chain INPUT (policy DROP)
> target     prot opt source               destination
> ACCEPT     all  --  xxx.114.183.1        anywhere
> ACCEPT     all  --  yyy.8.145.182        anywhere
> ACCEPT     all  --  zzz.68.137.158       anywhere
> ACCEPT     all  --  anywhere             anywhere
>
> Chain FORWARD (policy ACCEPT)
> target     prot opt source               destination
>
> Chain OUTPUT (policy ACCEPT)
> target     prot opt source               destination
>
> [root@prd-001 ~]# iptables-save
> # Generated by iptables-save v1.2.11 on Wed Aug  8 19:26:51 2007
> *filter
> :INPUT DROP [110564:24802104]
> :FORWARD ACCEPT [0:0]
> :OUTPUT ACCEPT [637061:352312072]
> -A INPUT -s xxx.114.183.1 -j ACCEPT
> -A INPUT -s yyy.8.145.182 -j ACCEPT
> -A INPUT -s zzz.68.137.158 -j ACCEPT
> -A INPUT -i lo -j ACCEPT
> COMMIT
> # Completed on Wed Aug  8 19:26:51 2007
>
>
> Trying to ssh to "aaa.bbb.216.35" fails with timeout, looking at
> tcpdump on the otherside shows no TCP handshack is made.
>   

You don't allow the return packets in. Add a -m state --state 
ESTABLISHED,RELATED match as the first rule in your INPUT chain.

HTH,
M4