Just a quick post this time on Lync Mobile client notifications.
Lync mobile app notifications on iOS and Windows Phone 7 devices will only work if you have dynamic federation.
The reason for this is because the app needs to be running to be able to receive notification and iOS and Win Phone 7 do not allow the app to run in the background to receive notifications. For other devices it just works.
Here’s what synamic federation is as explained by Lync Guy (@ http://ocsguy.com/2011/04/20/a-few-words-on-federation/)
Dynamic federation is a method where a partner company’s edge server is discovered by looking up an SRV record (_sipfederationtls._tcp.domain.com). Dynamic federation is perfect for an environment where users may need to add contacts from other companies quickly and without administrative intervention. The firewall will have to allow inbound connections to the access edge server on port 5061 from any potential partners, but for most companies who use open federation, they allow traffic from everywhere on this port to prevent needing administrative assistance.
So with the above in mind, if the company who hosts your external DNS does not support SRV records then you will not have dynamic federation or notification on your mobile clients who run iOS or Windows Phone 7.
Lync Mobile App Downloads link (probably easier to just go to your respective app store on your device)