Eric_27158
Nov 24, 2010Nimbostratus
GTM and DNS caching for UDP connections
Hey all, thanks for reading....
I've run into a situation where an outage to a GTM pool node causes problems with client-side DNS caching. For example, I have two nodes in a GTM pool and these guys are running SYSLOG. When one of them dies, even though it's removed from the pool and its IP won't be handed out, the DNS cache on client side is holding onto an IP that's now unreachable. So, our design problem is a balancing act (no pun intended). In other words, when you have a protocol like SYSLOG that uses UDP and will send many more DNS requests (depending on the TTL of the record), do you lower the TTL to something like 5 and hammer the F5 to death with DNS requests or is there another solution to hack at the client-side DNS cache or something that you all have determine is a "best practice" in situations like this?
Thanks and Happy Thanksgiving everyone...
Eric