Re: Problems filtering UDP with Netfilter

["pascal weller" <pascal@access.unizh.ch>]

<snip>
> iptables -A INPUT --protocol udp -i $DSLIFACE -d $ANYADDR \
>     --destination-port :1023 -j REJECT
> iptables -A OUTPUT --protocol udp -o $DSLIFACE -s $ANYADDR \
>     --source-port :1023 -j REJECT

all connections to low ports are rejectet at this point. So the next rule
will never match.
you have to put the ACCEPT-line before the REJECT-line

my setup is like this:

ACCEPT
ACCEPT
ACCEPT.....for everything i want to allow
LOG
DROP....all that didn't match so far

>
> # Allow UDP datagrams in and out on the allowed ports
>
> iptables -A INPUT --match multiport --protocol udp -i $DSLIFACE \
>     -d $ANYADDR --destination-port $UDP -j ACCEPT
> iptables -A OUTPUT --match multiport --protocol udp -o $DSLIFACE \
>     -s $ANYADDR --source-port $UDP -j ACCEPT
>
> I've been searching all over the web for information on Netfilter and
> how I could accomplish my goals with it. So far I've come up with more
> troubleshooting then anything else. I'm hoping that one of you experts
> might have some advice for an apprentice like me :-D

IMHO the only thing you need to read is:

http://netfilter.samba.org/unreliable-guides/


>
>
> Thanks
>
> Stef
>
>
>
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