> some servers like hotmail and mac.com (don't ask) don't seem to like > accepting messages from my server (and never have):
>
> Has anyone else experienced anything like this? If so, any suggestions?
Welcome to the wonderful world of dealing with Hotmail...
You're getting 4xx codes at the moment - that means "not yet". Keep an eye
on your mail queue to see if they'll accept that mail later.
If hotmail won't take anything from you, there are certain things you can
do to improve your chances: the most important is to look at SPF records.
Hotmail *claims* to want these - but in fact, its tests appear to be
somewhere between SPF and SenderID, supporting neither protocol properly.
Lastly, once you do get mail through, check that it actually gets
delivered. It will often end up in the "bulk" folder (i.e. tagged as
probably-spam), or often just gets discarded silently. I've yet to find a
way around that.
Your best bet is to leave Hotmail to their own intranet...
