[327] in linux-net channel archive
Re: UDP: bad checksum messages in syslog ?
daemon@ATHENA.MIT.EDU (Matt White)
Tue May 16 13:23:25 1995
Date: Tue, 16 May 1995 09:04:26 -0600 (CST)
From: Matt White <whitem@arts.usask.ca>
To: "Matti E. Aarnio [OH1MQK]" <mea@mea.cc.utu.fi>
cc: Arnt Gulbrandsen <agulbra@troll.no>, ganderson@clark.net,
linux-net@vger.rutgers.edu
In-Reply-To: <95May16.154951+0200eet_dst.69-1+54@mea.utu.fi>
On Tue, 16 May 1995, Matti E. Aarnio [OH1MQK] wrote:
> > > May 14 03:07:41 garc kernel: UDP: bad checksum. From 80B75CF1:138 to \
> > > 80B7FFFF:138 ulen 216
> >
> > From 128.183.92.241 Port 312 to 128.183.255.255 port 312. What's running
> > on that port, and what broken operating system is 128.183.92.241 running?
>
> No, the port-numbers are in decimal, while IP-addresses are in HEX.
> /etc/services has this line: netbios-dgm 138/udp
>
>
> > > May 15 06:59:23 garc kernel: UDP: bad checksum. From 00000000:67 to \
> > > FFFFFFFF:67 ulen 308
> >
> > This one's more weird. It's right of linux to log it, though, it's
> > unlikely that a packet claiming to come from 0.0.0.0 can actually be
> > valid, but the error linux logs isn't likely to be the actual error,
> > there's some more fundamental error, probably, which you'll probably need
> > a wizard and his sword (tcpdump) to find.
>
> That is a BOOTP-query with faulty software. To fully analyze it,
> the packet should be looked into, and senders ethernet MAC dug up
> from it. (But now the kernel throws it away..)
To be more exact, I saw this particular error a lot when I was testing
Microsoft TCP/IP-32 3.11b beta and the DHCP patches for bootp-2.4.3. The
machine seems to get a correct DHCP reply, but there must be something
broken in the Microsoft tcp stack...and since these machines periodically
refresh the IP reservation, I get a hit ever 5 minutes or so.
DHCP will be nice, tho, if they get it straightened out...
--------------------My real computer is an Amiga---------------------
- Matt White Matt.White@usask.ca -
- Network Technical Support whitem@arts.usask.ca -
- College of Arts & Science University of Saskatchewan -
---------------------------------------------------------------------
I used to think they were after me...
But they're just after my recipe.
- Joe Diffie..."Good Brown Gravy"
