hc_andy_35682
Feb 15, 2012Nimbostratus
F5 GTM - DNS timeouts after several nslookups
Hi All,
We are using the F5 GTM to be the authoratative dns for our sub-domain abc.xyz.com.
We've configured zonerunner with the relevant zone details and A records to serve dns requests for this zone.
My question relates to the fact that if I do a windows nslookup against the listener IP configured on the F5 (10.61.63.52), after about several nslookup (maybe 30+ times) I eventually get a dns timeout error (as seen below).
Does the F5 have some sort of protection mechanism that automatically blocks the same IP querying it after X amount of times??? I wouldn't think so, but asking anyway :)
This is significant to us because we have a set of windows dns servers that are set as our primary dns servers on our PC's. The windows DNS servers have a forwarder configured on them to the F5's listener IP to handle any requests for abc.xyz.com.
Every now and then we will have DNS issues with resolving myhost.abc.xyz.com and the Windows guys are saying that there is nothing wrong with their DNS server and point to the fact that if they do a direct lookup on the F5's listener IP as seen below, it eventually times out - so it's a F5 issue!!
Is this just a bug with the Windows nslookup too??? Are there any checks/logs on the F5 that we can do to rule out it being an issue with the F5.
> myhost.abc.xyz.com
Server: [10.61.63.52]
Address: 10.61.63.52
Name: myhost.abc.xyz.com
Address: 10.61.34.10
> myhost.abc.xyz.com
Server: [10.61.63.52]
Address: 10.61.63.52
Name: myhost.abc.xyz.com
Address: 10.61.34.10
> myhost.abc.xyz.com
Server: [10.61.63.52]
Address: 10.61.63.52
DNS request timed out.
timeout was 2 seconds.
Name: myhost.abc.xyz.com
Address: 10.61.34.10
> myhost.abc.xyz.com
Server: [10.61.63.52]
Address: 10.61.63.52
Name: myhost.abc.xyz.com
Address: 10.61.34.10
Thanks.
Andy