GTM and DNS caching for UDP connections

Thanks for your tips naladar. Unfortunately, we have a bunch of TCP VIPs and RADIUS where the transaction requires the srcIP to be intact and the response to work. Removing SNAT breaks the session if you're routing to the backend host. We are utilizing the X-Forwarded-For field for HTTP/HTTPS, and you're right, that works great. As you can see, the GTM's ability to do DNS-style load-balancing solves both of our issues but brings in the new issue of TTLs when a pool member fails.... if a backend machine fails, the outage could be as long as the TTL for certain clients. I'll throw this question back out to the masses (hopefully others are reading!), what do people do with their DNS TTLs in cases where your GTM points to actual machines as pool members ?