Dears,

We have outlook clients get disconnected randomly in branch sites from exchange 2013 and connect randomly back again...I suspect MTU value is the issue but how can I verify this? note that in main site (in which exchange is installed) outlook is working fine.

I did the below to troubleshoot this issue:

1. Pinging mail.domain.com works fine with some network delay
2. Trace route from client to mail.domain.com and it shows direct connection while it should not, they are in two different vlans (main site and branch site)
3. Test email auto configuration and it works even outlook is disconnected (which do not make sense)
4. Test accessing OWA, it worked but it is slow
5. Test creating new outlook profile, it worked but hanging .. seems got into timeout while configuring in the wizard

rom the behavior above it seems to me there is some network issues preventing stable connection for your outlook clients in branches to exchange and I am not sure if MTU is the issue.

• Edited by Ahmad K. Jayyusi 50 minutes ago