[lug] Postfix and M$ smtp question

[Egg]

I am curious if anyone has any idea why requests for mail delivery
times-out when delivering to the following domains:

hotmail.com
msn.com
pinpointtech.com


The only thing that I can think of is that they are M$ based and thus
aren't as likely to cooperate, but I find this a niave assumption to
make so I was wondering if anyone knows what could be possible
cause(es).

Thanks in advance.

Egg