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Wireshark-users: Re: [Wireshark-users] DNS Working but can't connect to anything

From: "Jim Young" <sysjhy@xxxxxxxxxxxxxxx>
Date: Tue, 27 Jan 2009 00:32:33 -0500
>>> staedtlerx <staedtlerx@xxxxxxxxx> 1/26/2009 11:16 PM >>>
> I tried NetMon - it appears to output the same exact info that Wireshark
> does. Should I somehow be invoking more info?

The two traces you sent both indicate that the Sony system (192.168.0.2) 
--- the system that initiated the DNS queries --- is actually rejecting the DNS 
replies it asked for!

The two ICMP  "Destination Unreachable (Port unreachable)" messages
within each trace are responses generated by your host (192.168.0.2) in 
response the DNS response packets.

I've seen similar behavior when someone's workstation based firewall is 
mis-configured, when multiple NIC cards are installed and mis-configured
or also (rarely) when the application that initiated the DNS request is no 
longer listening on the UDP port that the request was initiated from.   

FWIW: I doubt that your ping or tracert initiated DNS requests resulted 
in the UDP port itself to be closed so soon after the requests was sent.  
Generally speaking the Windows DNS stub resolver uses the same 
ephemeral UDP port for all requests until the system is rebooted.  The 
nslookup tool on the other hand uses a new ephemeral UDP port 
for each DNS request.  

It's seems somewhat odd that your system sends two DNS requests 
so close in time to one other, but these are NOT duplicate packets, 
each DNS request has a unique incrementing ip.id value.

Someone suggested that you show us a copy of how routing in 
configured on this Windows machine.  You can generate this report 
from a Windows cmd shell with the either of the following commands:

   route print

or

   netstat -r

Also a complete copy of your workstation's complete ip setup might 
be useful:  e.g.

   ipconfig /all

Perhaps attaching the output of these two reports might shed some 
light on what may be going on.

Best regards,

Jim Y.