Re: bind() udp behavior 2.6.8.1

[Adam Denenberg]

I disagree.  The linux server should be using unique Transaction ID's 
in the dns header for each unique dns request.  Otherwise there is no 
way to distinguish them (same A record request).  Of course the 
firewall is going to drop a reply that it thinks it already saw a reply 
for 30ms ago.

This appears to be a bug in the way glibc is handling things but i 
cannot be sure.  That is the goal of my investigation.

adam

Please CC me i am not on the list.

On Dec 15, 2004, at 2:07 PM, Jan Harkes wrote:

> On Wed, Dec 15, 2004 at 09:16:02AM -0500, Adam Denenberg wrote:
> > the Firewall from distinguishing unique dns requests.  It sees a 
> > second
> > DNS request come from the linux server with the _same_ transaction ID 
> > in
> > the UDP header as it is marking that session closed since it already 
> > saw
> > the reply successfully.  So for example the linux server is making a 
> > dns
>
> Stupid guess here,
>
> The reply got dropped after it passed your firewall and before it
> reached the linux server. What you are seeing is simply a retransmit
> which would also have happened if the original request got lost, or if
> the reply was dropped before it reached your firewall, in which case 
> the
> firewall probably would have forwarded the retransmitted request 
> without
> a problem.
>
> I would open the window before you throw the piece of garbage out.
>
> Jan
>
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