On Fri, May 17, 2002 at 01:02:04PM +0100, Antony Stone wrote:

> On Friday 17 May 2002 12:52 pm, Axel Heinrici wrote:
> 
> > > iptables -A icq -p tcp --dport 5190 -d login.icq.com -j ACCEPT
> > > iptables -A icq -p tcp --dport 5190 -s login.icq.com -m state
> > > --state ESTABLISHED,RELATED -j ACCEPT
> > > iptables -A icq -p tcp --dport 5190 -s icq.com ! --syn -i
> >
> > Is this allowed. I thought ippables/netfilter does not make a DNS
> > lookup. Or did you mean: "look it you yourself and replace it"
> 
> Yes, this is perfectly okay - however you must remember that the lookup is 
> done once, when you enter the rule, and the machine then stores the IP 
> address which results from the lookup.

What happens if a name resolves in several IP's? Is it not wiser to
look it up manually and add multiple rules according to the number of
A-RR?

Ramin

> 
> You are correct in thinking that it's not possible to enter a hostname in an 
> iptables rule and then get the system to resolve it every time it sees a 
> packet come through (thankfully).
> 
> 
> Antony.

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