From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martijn Lievaart <m@rtij.nl>
Subject: Re: psd and active ftp mode
Date: Wed, 09 Apr 2003 13:03:49 +0200
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To: Peteris Krumins <newsgroups@lf.lv>
Cc: netfilter@lists.netfilter.org

Peteris Krumins wrote:

>hello,
>
> i was just testing psd match and w/ ftp active mode.
>
> I created 10000 files on the ftp server and set my ftp client to
> active mode and let it download those files while having
> `iptables -A INPUT -p tcp -m psd -j REJECT --reject-with tcp-reset`
> (with psd default threshold/weigh values).
> The psd matched 3136 packets.
>
> Ftp server went mad issuing:
>  425: Unable to build data connection: Connection refused
>
> This means i cannot relay on psd and block 'possible portscans'?
> Any suggestions?
>
> The same would happen, if i created some rules with limit match..
>
>  
>

I never have this problem. I think you should accept RELATED before the 
psd match.

Martijn