Exchange 2013 OWA login loop - External Access Only

Marcus Wong Theen Nam 1,131 Reputation points
2022-03-09T08:14:18.083+00:00

Our Exchange 2013 servers are having OWA login loop when accessing it externally. While accessing it through localhost or IIS ARR (DNS record points to IIS ARR for mail.domain.com) there's no looping issue.

External CAS routing:
Public DNS record > Firewall > NAT to IIS ARR > Forward to Exchange 2013 CAS servers

Internal CAS routing:
Internal DNS record > IIS ARR > Forward to Exchange 2013 CAS servers

Since I can access it from internal network by pointing client machines to Exchange server directly and also to IIS ARR. I can see the issue should be from the Firewall.

Any idea guys?

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,669 questions
{count} votes

2 answers

Sort by: Most helpful
  1. Andy David - MVP 149.2K Reputation points MVP
    2022-03-09T12:17:30.39+00:00

    Yep, I would start with the firewall, and check the logs there to see what happens when someone connects externally and if its routed correctly.
    If it is, work your way to the IIS ARR and check logs, then finally to the Exchange Server.

    0 comments No comments

  2. Andy David - MVP 149.2K Reputation points MVP
    2022-03-10T11:46:28.317+00:00

Your answer

Answers can be marked as Accepted Answers by the question author, which helps users to know the answer solved the author's problem.