Author: Chris Sykes Date: To: Hampshire LUG Discussion List CC: hampshire Subject: Re: [Hampshire] Are UDP responses allowed from a different source
port?
On Fri, Nov 06, 2009 at 08:59:52PM +0000, Nick Chalk wrote: > So, the question is whether this is correct
> behaviour on the part of the Linux box. I've yet
> to find a reference to UDP that mentions filtering
> on the source port of a datagram. The destination
> port obviously has to be correct, but I'm unclear
> on whether the source port also has to match.
>
> Has anyone seen this behaviour before? Any
> references?
I believe that if you call connect() on a UDP socket, then you will only
receive datagrams from the IP/port that you have "connected" to so it
could be that is what your monitoring program is doing.
An strace (or the source if you have it) should be able to confirm this.
