syslog: "ip length 328 disagrees with bytes received 332"

David W. Hankins David_Hankins at
Fri Jul 28 17:08:14 UTC 2006

This is a problem with some network drivers.  They store more data down
the socket than exists in the IP packet (eg including the 4 byte hardware
ethernet checksum at the tail end of the packet...generally never seen
by software).

I have a submitted patch queued to work around this within dhcpd, the
intent of which is to permit ip packet lengths that are less than the
size of the received data block, ignoring the trailing bytes, but it
failed review (it appears to use the contents of the ip header
directly without bounds checking in a call to memcpy()).  It would
have been in 3.0.5b1 if I had had the time to correct will
be in a 3.0.x maintenance release in the future.

But truthfully this is a bug in your network driver.

On Thu, Jul 13, 2006 at 05:12:04PM +0200, Adalbert Netzer wrote:
> My Problem:
> the syslogs are full of the messages like this:
> "dhcpd: ip length 328 disagrees with bytes received 332"
> "dhcpd: accepting packet with data after udp payload"

David W. Hankins	"If you don't do it right the first time,
Software Engineer		you'll just have to do it again."
Internet Systems Consortium, Inc.	-- Jack T. Hankins

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