Messages in this thread | | | From | Nigel Metheringham <> | Subject | Re: Kernel messages | Date | Tue, 28 Oct 1997 17:55:58 +0000 |
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chris@ferret.lmh.ox.ac.uk said: } I got these (see below). What are they all about? I don't have any } masquerading rules defined! Although I believe I do have masquerade } support compiled in.
} MASQ: failed TCP/UDP checksum from x.x.x.x! } MASQ: failed TCP/UDP checksum from x.x.x.x!
Oh, what an interesting side effect....
If you have masq compiled in, all incoming packets destined for a local address will pass through the masq checks. Since masq involves rewriting packets and regenerating the checksums, quite early on it checks UDP/TCP packets for correct checksums on the basis that rewriting a broken packet is a waste of time. Nothing else reports broken checksums at all, but the masq code does (at too high a level of message in retrospect).
} Is someone trying it on??
No, just some broken kit or wiring out there...
I guess that it may be time to look at that code and see if we can speed it up by moving the checksum check after the relevance check. You may only get this if the packets are destined for a port about 60000 - need to check code for that.
Nigel.
-- [ Nigel.Metheringham@theplanet.net - Systems Software Engineer ] [ Tel : +44 113 251 6012 Fax : +44 113 224 0003 ] [ Friends don't let friends use sendmail! ]
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