Exchange ActiveSync on Internal Network

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Level 1

7 points

Exchange ActiveSync on Internal Network

Hi Geniuses,

I've got a current issue with iOS5 Devices were deploying Campus-wide (iPhone and iPad). Being a Government Entity we run a Split DNS

setup which works well for most things.

However here's the issue.

Exchange 2010 is setup with ActiveSync, If we set iOS devices to Sync we use the external facing DNS entry of mail.myschool.wa.edu.au

Requests to this address run back through an offsite DNS, through a TMG Gateway and then back to our Exchange Server via NAT. The external

sync works flawlessly.

The problem is INTERNAL sync. It will not connect to Exchange Activesync on our Internal VLAN's. If we connect iOS5 devices to the local WiFi, it connects fine to the WiFi, DHCP Allocates addresses fine.. just not EAS.

I can ping mail.myschool.wa.edu.au fine so the split DNS resolve is working fine. If i create a new IMAP mailbox to the Exchange Server whilst connected to the local WiFi it sync's fine with no problems.. So its seeing Exchange no problems..

But.. It just will not connect on 443 (https).

Ideas? Could it be a self-signed Certificate issue internally?

Chris

iPhone 4, iOS 5.0.1

Posted on Dec 1, 2011 6:55 PM

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Answer 1

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hamgatan Author

Level 1

7 points

Dec 5, 2011 9:32 PM in response to hamgatan

Have worked out the Solution now.

Problem is the DNS order priority was all skewed. The offsite DNS was given preferential selection in resolving mail.myschool.wa.edu.au as opposed to the Internal. The Offsite only redirected the page back to the TMG Gateway, not the Internal NAT Mapped Exchange Server.. Once we changed the DNS Order Priority, the Internal DNS kicked in first and auto-resolved the Exchange Server locally instead.

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Answer 2

upd

Level 1

8 points

Jul 6, 2016 11:23 AM in response to hamgatan

That solved my problem. Even though my DHCP server assigning the IP address to the iOS device was configured to provide the internal DNS server first, followed by an external DNS server, for some reason the iOS device was only picking up the external and unable to configure the ActiveSync account properly.

I can now use ActiveSync both inside and outside my home network.

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