Date: Thu, 4 Sep 1997 17:15:21 +0200 (CEST) From: root@deadline.snafu.de (Andreas S. Wetzel) To: rbezuide@oskar.nanoteq.co.za (Reinier Bezuidenhout) Cc: mickey@deadline.snafu.de, bugs@FreeBSD.ORG Subject: Re: Bug in IPFW code ? Message-ID: <m0x6dcv-000Br6C@deadline.snafu.de> In-Reply-To: <199709041511.RAA11819@oskar.nanoteq.co.za> from Reinier Bezuidenhout at "Sep 4, 97 05:11:06 pm"
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Hi! --- Reinier Bezuidenhout writes: ] > 230 Deny log udp from any to 194.121.229.32/28 111 via sl0 ] > ] > This rule should drop udp packets to the sunrpc port coming in via interface ] > sl0. But instead it seems to deny random udp traffic to my network: ] > ] > Sep 4 16:13:09 gw-deadnet : /kernel: ipfw: 230 Deny UDP 130.83.22.1:17993 194.121.229.34:17732 in via sl0 Fragment = 123 ] ] Yes I also have experienced this problem, it has to do - as far as I ] can recall - with the sequence of how the check is done in ip_fw.c ... ] ] The fragments after the first one doesn't have the ports etc set any ] more, but some checks are still performed and sometimes they match ] and causes this to happen. ] ] A temporary solution is to set the MTU for the slip line to 1500 ] (this may degrade through put if you have a shaky line - I think) but ] seemed to solve the problem for now. I will check this, although I think on a 33k6 analogue line this will be some sort of ugly :-/ ] You are runnng a 2.1.X releas, probably 2.1.7 right ??? I had a look ] at the filtering code in 2.2 and the sequence of checks has changed ] there and "should" solve this kind of problem. This is happening on a 3.0-current box as of 08/30/97. Regards, Mickey -- (__) (@@) Andreas S. Wetzel Mail: mickey@deadline.snafu.de /-------\/ Utrechter Strasse 41 Web: http://cenotaph.snafu.de/ / | || 13347 Berlin Fon: <+4930> 456 066 90 * ||----|| Germany Fax: <+4930> 456 066 91/92 ~~ ~~
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