Outlook client connectivity

[ataylor]

I'm experiencing a bizarre issue with one of our network switches that only seem to be affecting outlook connectivity for users that I have migrated to Office 365 - I have isolated the issue to a SGE2000 24 port switch, its currently there as a stop gap as it has replaced a switch that died a few months ago, I'm just waiting until I can purchase a Netgear switch to replace it.

 

If I plug a client into the other switch in the same Cab, outlook starts working. I've updated firmware on the switch, reset it to factory default and even updated the nic drivers on the affected computers.

 

Any ideas what might be causing this sort of behavior??

[ataylor]

My troubleshooting ability in wireshark is limited but this entry seems to stand out in comparison to a machine that connects successfully. Successful clients tend to connect outlook.office365.com first. Maybe its a DNS issue?