We are having some of our users tell us that they are at random intervals getting kicked out of Exchange 2013 OWA. It is on various browsers both on our network on off-site. We have 2 CAS/DB servers and 2 DNS A records pointing (one pointing to each) for failover purposes. Ex. outlook.domain.com > 192.168.1.1 (server 1) and outlook.domain.com > 192.168.1.2 (server 2). I am told the DNS entry should work and is normally the way to do failover. Although, I read another post that said it may cause the issue we are having. We recently migrated from Exchange 2007. And there just isn't much out there saying a lot about the issues we are having that I can find. Aside from all that... We are having random users dropped in OWA at random times, on random machines, using random browsers, and at random locations. Any help pointing us in the right direction would be greatly appreciated.
Hi,
Are you using Firewall in your environment? Please check the Firewall configuration for OWA:
https://technet.microsoft.com/en-us/library/cc995140.aspx
Additionally, please collect any event logs in Event Viewer or IIS logs for further analysis.
Regards,
We solved this issue - partially. It was DNS Round-Robin. While DNS Round-Robin should work, for some reason, with 2013 it was causing us to lose connection. My thought is that DNS RR would somehow connect a user to one CAS server and then for some reason they would connect to the other CAS server and thus lose their session and have to re-authenticate. This was happening in just a very few minutes and constantly.
Anyway, removing the second DNS entry to OWA (CAS server 2) solved our problem of disconnections. But, it also leaves us without any automatic failover.
- Marked as answer by Winnie LiangMicrosoft contingent staff, Moderator 5 hours 2 minutes ago