SfBForMac/16.3.241 Autodiscover and System Security Logs

[Dirk van Assendelft]

This behavoiur is both with SfBForMac/16.3.241 & SfBForMac/16.2.156

We are a hybrid deployment, and the autodiscover DNS record still points to on-premise (Exchange 2010).  Our autodiscover endpoint (2010 CAS server) is getting hammered with autodiscover request and login/log off events.  We are seeing upto 35,000 events per user every 15 minutes from SfBMac clients.  

Although it is not currently causing any direct issues, that is a LOT of traffic (and logging) to our domain controllers and CAS servers.    Right now it a very small number of users, but this can rapidly become a major issue if more people upgrade to SfBForMac/16.x.x.

Is this expected behaviour?  How do we stop this?

[#2]

Just to clarify, there is NO on-premise Lync/SfB. The hybrid deployment is for email only. 95% of our mailboxes are in cloud; 100% of our Skype for Business is in cloud.

[#3]

Having the same issue on build SfBForMac/16.3.240

Very same setup with hybrid, internal autodiscover and all users in O365.

Thoughts?

[#4]

Hi Dirk, SFB Mac client does query the Exchange web service for the list of meetings. But we don't expect a huge load on CAS, especially after the Mac client is already connected. Would you be able to use the Insiders build to file an issue so that we can see the auto-discovery sequence?

[#5]

Also seeing massive onPrem Autodiscover traffic from SFBforMac in hybrid mode. All mailboxes and SFB are in O365.   This is in addition to very high Mac client autodiscover traffic in general. Any remedies?

[#6]

Just got this; filed an issue with Fast Insider build. Thanks!