For more information regarding the security incident at F5, the actions we are taking to address it, and our ongoing efforts to protect our customers, click here.

Forum Discussion

Brian_69413's avatar
Brian_69413
Icon for Nimbostratus rankNimbostratus
Jul 09, 2013

Pool member selection based on DNS entry

I am looking to use the POOL command in an iRule to select a pool member based on a DNS response from the RESOLV::lookup command. Does the POOL command require that the selected 'member' actually be ...
application delivery
dev
devops
iRules
Brian_69413's avatar
Brian_69413
Icon for Nimbostratus rankNimbostratus
Jul 09, 2013
Your assumptions are correct and I understand the DNS query latency, but we have a web app that sends data every 5 minutes and needs to send that data to the active site which is determined by a service entry in DNS. We are using the LTM for outbound data sends in order to do application layer filtering/translation. My understanding is that the RESOLV function does cache and that cache could be adjusted, but the TTL of the external DNS entry is set very low (<20 seconds). Is there some notion of expiring the cache in the table entries?