Forum Discussion

suresh09_292033

Nimbostratus

Jan 23, 2018

Solved

Fall back IP

What i understanding regarding fall back IP is that if all virtual servers in pool associated with wide ip are down then DNS will resolve to fall back ip but in my scenario it's happening differently...

application delivery

BIG-IP DNS

devops

Jason_Brown_314
Jan 31, 2018
You need to have the alternate set to fallback for this to use that IP entry.

Also, just to expand - I have just experienced this too and I understand that there is a level of caching done within DNS express in order to try to expedite the reply, you are also using a LDNS (presuming 10.10.10.10 isn't the DNS listener) to resolve this host you could get old answers. I disabled DNS express in my profile and it worked as I expected it should.

being new to the GTM I am also still learning, so this is based on my troubleshooting only.

kolom

Altostratus

Jan 25, 2018

Hello suresh,

This behavior is caused by using "Return to DNS" as a fallback method.Return to DNS drops the resolution to BIND. When this mode is used, the typical response will be a list of all virtual servers associated with the Wide IP.