ons, 2002-04-24 kl. 19:45 skrev doggy:

Disregarding NAT:

> #6665
> iptables -A FORWARD --in-interface eth0 --out-interface ppp0 --protocol tcp 
> --source $LAN --destination !  $LAN --sport $HIGHPORTS --dport 6665 -j 
> ACCEPT

> # Do I really need this rule ??
> # Or can a Attacker get with this rule into my lan with source port 6665 ?
> iptables -A FORWARD --in-interface ppp0 --out-interface eth0 --protocol tcp 
> --source ! $LAN --destination  $LAN --sport 6665 --dport $HIGHPORTS -j 
> ACCEPT

He most definitely can. You would combat this with out uses "-m state
--state NEW etc" and in uses "-m state --state ESTABLISHED etc".

For in to fresh UP ports, you would use: "-m state --state
ESTABLISHED,RELATED etc.".

Tony
 
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Tony Earnshaw

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