Occasional issues sending appointments to external contacts

[ColdFlame]

Hi all,

Hoping someone can help me.

I have users in my environment that regularly send appointments to outside individuals. These appointments sometimes make it, other times do not. If they do not make it, they send Delay notifications to the sender and will eventually fail after a few days with an Undeliverable bounce.

The way I have things set up is this:

Exchange 2003 running on Windows 2003 R2 - both fully service packed

My Exchange server sends all mail through my Ironport spam filter. All inbound mail and appointments route through our Ironport device, and on to the Exchange server.

The other odd thing is, when I can confirm one of these appointments hasn't gone through, it appears in the Message Tracking Center, yet I can't find it in my Ironport logs (meaning it never got there).

Any suggestions would be most helpful. I'm extremely confused and out of ideas/options at this point.

Cheers,

ColdFlame

 

[ColdFlame]

I am really hoping someone can weigh in on this with me. Further to my above note, almost every time this appears to be an issue, it seems to be with changed appointments. ie: updated time, place, date, etc...

They never leave our network and this is frustrating many people, most importantly, our CFO. Please help!!!

Cheers,

ColdFlame

 

[ColdFlame]

Thusfar, I believe this has corrected the issue:

http://support.microsoft.com/kb/938650/en-us

That being said, this is not specific to just sending to other versions of Exchange servers with external domains. This issue was happening to us for a multitude of addresses including @gmail.com, @hotmail.com, @yahoo.com, etc... and I am 99% sure those guys don't use Exchange.

As well, despite what Microsoft's article says, you *do* need to reboot after applying the fix. And don't forget to add the registry key post-fix.

I will update if this hasn't permanently fixed it, but as this moment, things are working as expected.

Cheers,

ColdFlame