Hello,
We recently added an HAProxy load-balancer for our Exchange server, and everything runs fine through it.
Then, we decided to change the internal records (autodiscover, ews, mail) to also point to those HAProxy (because we have some services using EWS that can gain from having the connectivity to the Exchange servers load balanced). Before that, the internal DNS records were pointing directly on the Exchange servers.
Sadly, after doing so, the Instant Messaging on OWA stopped working, and the logs were showing SignIn Timeout. We made sure the S4B servers are well allowed to contact the HAProxy, we saw EWS and Autodiscover flow without issues, but still it wouldn't work.
So to summarize:
S4B Servers --> (resolve DNS) --> Exchange Servers: OWA IM Working
S4B Servers --> HAProxy(s) Virtual IP --> Exchange Servers: OWA IMnot Working
As soon as we changed the Hosts file on the S4B front end servers to point back to Exchange Servers directly, it worked back.
Does anyone have any experience with this? Is this scenario not supported?
Thank you