iptables: drop or reject?
John Summerfield
debian at herakles.homelinux.org
Wed Oct 31 01:27:29 UTC 2007
Bill Davidsen wrote:
> Ashley M. Kirchner wrote:
>>
>> To drop or not to drop, that is the question. If there's a server
>> out there sending spam e-mail, and I use iptables to block it, is it
>> best to simply drop the packet, or should I do a '--reject-with
>> icmp-host-unreachable' (or 'icmp-port-unreachable') or just a
>> 'tcp-reset'?
>>
>> Basically, if I just drop the packet, the server in question would
>> simply continue to send stuff, wouldn't it? As far as it knows, its
>> spam reached the destination, whereas if I send something back, it
>> might actually acknowledge and stop? Yes? No?
>>
> If you drop, the sending host will often keep sending SYN packets until
> it decides you are talking, maybe 3-10 packets.
If that were true, I would expect to see them in my log summary, and I
don't.
--
Cheers
John
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