On Friday 17 May 2002 1:35 pm, Ramin Alidousti wrote:

> 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?

Yes, it is wiser to do the lookup yourself and be specific in the rule.

If you get the system to do it for you (as above), then you will get a rule 
containing only the first IP address returned from the lookup.


Antony.

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