Load balancing Exchange CAS traffic from single source(s)

Hello-

The "clumping" you're seeing only happens if you do persistence (Microsoft calls this "affinity") based on source IP address.

F5's Deployment Guide for Exchange Server 2010 and 2013 is available at http://www.f5.com/pdf/deployment-guides/microsoft-exchange-2010-2013-iapp-dg.pdf

In that guide, we recommend "cookie" persistence for OWA traffic, and persisting on the Authorization header for ActiveSync. Neither method would exhibit the behavior you're seeing.

If you use F5's iApp for CAS (see more info here: https://support.f5.com/kb/en-us/solutions/public/13000/400/sol13497.html?sr=35799426), the correct persistence types will be set up automatically.

Please let us know if that helps with the issue you're seeing!

-Dayne