2014-03-20

Wireshark: DNS: dns.time misleading

From a windows machine with 2 DNS servers configured via DHCP:

packet 1: 44.667  to DNS1
packet 2: 45.667  to DNS1
packet 3: 45.667  to DNS2
packet 4: 46.009 response from DNS1

all of the 3 packets, i.e. DNS Queries share the same ID (should this be?)

Wireshark calculates the time difference (dns.time) between packet 2 and 4 and not between 1 and 4!

So when you create a graph, the time difference looks ok, i.e. some 300 ms but actually it was 1300 ms.

Windows per default will resend DNS queries to all configured DNS servers after 1 second! That is packet 2 and 3.


  • Why is the ID the same? Is this a must or a bug?
  • What can I do to get the real time difference?


This is where I got the info on how to graph dns.time:

http://ask.wireshark.org/questions/3678/dns-transaction-latency

I use dns.time AVG(*) dns.time and Dot.


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