Re: Tightening up outgoing traffic

[Kjetil Andreas Laasby <list@laasby.com>]

Problably because yahoo.com lies in your local DNS cache or on an cache
server behind your firewall.

add
iptables -A OUTPUT -p tcp --destination-port domain -j ACCEPT
iptables -A OUTPUT -p udp --destination-port domain -j ACCEPT

also.

You should also open up RELATED ICMP to minimize delay for errors.

hth,
Kjetil Laasby.

> All:
> 
> I am running directly off the firewall box.  I currently have the
> following:
> 
> iptables -P OUTPUT ACCEPT
> 
> When I change to this:
> 
> iptables -P OUTPUT DROP
> iptables -A OUTPUT -p tcp --destination-port http -j ACCEPT
> 
> I keep getting "domainname can not be found.  Please check the name and
> try again" from my browser.  This only happens for new web sites (i.e.,
> Yahoo works fine).  As this seems somewhat like a DNS issue, I tried
> adding this:
> 
> iptables -A OUTPUT -p tcp --destination-port nameserver -j ACCEPT
> 
> but it didn't work.  Any ideas?  Thanks.
> 
> Neil Hodge
> 
> 
>