Peroidic DNS lookup failure for a alias record, but works fine for the parent WIP.

Hi, I'm seeing a strange issue where parent WIP works fine with no DNS lookup failures, but DNS lookup for the alias record on the same WIP fails periodically.

 

Example: I have a WIP with name 'tools.marketinglink.com', I have added a alias 'tools.marketinglink.uk' for the same WIP. Now, the DNS response for 'tools.marketinglink.com' works fine, but for 'tools.marketinglink.uk' fails periodically.

 

I see many complaints from clients. I don't know how to check the DNS lookup from LTM / GTM for the alias record. Can you please help me with the commands that helps me to troubleshoot this issue? Also, why is this issue caused? When WIp and its alias are serviced from the same pool of servers, why the lookup for the alias record fails, but for the WIP record it is successful throughout.

 

thanks, Lokesh