Date: Mon, 9 Feb 2015 22:21:31 +0100 From: Andre Albsmeier <andre@fbsd.ata.myota.org> To: Freddie Cash <fjwcash@gmail.com> Cc: freebsd-net <freebsd-net@freebsd.org>, lev@freebsd.org, Matthew Seaman <m.seaman@infracaninophile.co.uk> Subject: Re: Problems with IP fragments (was: Problems with DNSSEC -- answer in fragmented UDP doesn't work) Message-ID: <20150209212131.GA32613@schlappy> In-Reply-To: <CAOjFWZ4KVyYe65ggiHxy3SSw7MPMgx-0kD5ccfXOM%2BftwncP1A@mail.gmail.com> References: <54C918D2.7090805@FreeBSD.org> <54C91E80.7020407@infracaninophile.co.uk> <54C92222.6000201@FreeBSD.org> <CAOjFWZ4KVyYe65ggiHxy3SSw7MPMgx-0kD5ccfXOM%2BftwncP1A@mail.gmail.com>
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On Wed, 28-Jan-2015 at 10:04:57 -0800, Freddie Cash wrote: > On Wed, Jan 28, 2015 at 9:53 AM, Lev Serebryakov <lev@freebsd.org> wrote: > > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA512 > > > > On 28.01.2015 20:38, Matthew Seaman wrote: > > > > > What do you get if you run the reply size test at DNS-OARC ? > > > > > > https://www.dns-oarc.net/oarc/services/replysizetest > > 0 lines (empty answer) at CURRENT, only "rst.x1013.rs.dns-oarc.net." > > on 9.3. > > > > Looks like "IP Fragments Filtered", but I don't understand — why and > > where?! > > > > I'm using ipfw on both hosts, but I don't have any special rules > > about IP fragments at all! And as these systems are in completely > > different networks, with different uplinks and FreeBSD versions! > > > > IPFW doesn't deal with IP fragment reassembly by default. > > You can add something like the following to the start of the IPFW ruleset > to work around it (one for each NIC): > > $IPFW add reass ip from any to any in recv $NIC0 > $IPFW add reass ip from any to any in recv $NIC1 The ipfw man page says: Usually a simple rule like: # reassemble incoming fragments ipfw add reass all from any to any in is all you need at the beginning of your ruleset. However, I could never make this work. It eats all fragments but the resulting final packet never makes it. I am back to ipfw -q add 1 pass udp from any to $myip frag in recv $ifc as I need it only for UDP. Frag reassembly in pf works well on the other hand... -Andre > ... > > -- > Freddie Cash > fjwcash@gmail.com > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" -- A fool with a tool is still a fool.
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