nanog mailing list archives

Re: Fkiws with destination port 0 and TCP SYN flag set


From: Marcin Cieslak <saper () saper info>
Date: Wed, 17 Jun 2015 09:30:47 +0000

On Wed, 17 Jun 2015, Maqbool Hashim wrote:

It is always the same destination servers and in normal operations
these source and destination hosts do have a bunch of legitimate flows
between them.  I was leaning towards it being a reporting artifact,
but it's interesting that there are a whole set of Ack Reset packets
from the destination hosts with a source port of 0 also.

So the destination host is sending ACK+RST with the *source* port
set to zero, or the *destination* port?

Does this not indicate that it probably isn't a reporting artifact?

I would just tcpdump on one of the source machines to find out.

~Marcin


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