I thought I'd share this with the board as it may cure SOMEONE's frustration and allow them more free time to go shooting.
Understand the following is over a course of several weeks (Hey, I had to get some shooting in!)
So in the process of migrating exchange servers, I notice that all of a sudden I cannot send to hotmail/msn. I would get a "delay" message and then after a couple days I would get a Non delivery message.
At first I thought I may have misconfigured the system. SO, after several attempts at reconfiguration and test messages with no avail, I started to suspect that I was blacklisted for some reason. checked into that with nothing coming up for any of my domains.
I then began to wonder if hotmail itself had decided to block my IPs or even my subnet. I attempted a telnet session with their MX server on port 25, did a test message via the console, and IT DELIVERED!!! Out of pure frustration, I decide to reboot. All the messages in my outbound queue DELIVERED! So Here I thought I had fixed it with a simple reboot . I was wrong. Later that day my fiance tried to send some email to a couple of customers at their hotmail addresses, and she gets a delay message.
Now I'm getting pretty frustrated, I reboot the server and VOILA! they deliver, but later, again, nothing. I had done some google searches before but not come up with any real answer. By luck THIS time, I came across this entry in google groups. Turns out that if you have Symantec Antivirus installed with the "Internet E-mail Auto Protect" enabled it can alter the headers and hotmail don't like it. Odd that they were the only ones that I had a problem with, but it appears that the problem has been fixed. The only explanation I can come up with for why they were delivering after reboot was that the Auto protect service had not started yet.
Cliffs Notes Version for those who don't feel like reading my long winded paragraph:
Exchange Server 2003 on Windows Server 2003 running Routing and Remote Access
Symantec Client Security 10.0.1.1000
BE SURE TO DISABLE THE "INTERNET E-MAIL AUTO PROTECT"
The "Microsoft Exchange Auto-Protect" feature will do just fine with the above disabled
lol norton is notorious for problems like this. i remember at one point if a email subjiect line was capitolized. the email scanner would not even scan the message. it would just let it through.
im not a big fan of their antivirus products
thanks for the heads up though