Exchange ActiveSync internally

Hi all,

New to this forum and also new to UTM's and Astaro!

We recently moved to a new building and got an Astaro UTM. Everything (well almost) has been running great up till now!

We have Exchange Active sync running and from outside the building that is working great! I have a DNAT rule in place from Any > HTTPS > External WAN interface destination Internal Mail Server > HTTPS

This is working as you would expect. We dont have a domain name associated with Active Sync and our phones are just pointing at our public IP.

However when in the building and on Wireless Active Sync fails to connect. I cannot telnet to public IP on 443 despite the firewall log showing:

10:16:15 Connection using NAT TCP
10.0.0.55 : 62746
→
78.141.22.122 : 443
[SYN] len=52 ttl=128 tos=0x1c srcmac=68:b5:99:f9:5e:d3 dstmac=0:1a:8c:32:4:c0

Anyone have any ideas as to how I can get it working internally without a domain name in place. In our previous building with a Cisco Small business Firewall it worked without and problems or configuration other than port forwarding.

Thanks for any help!