je t’aim MS Exchange – not!
Seriously. We’re using Exchange as our group and mail server. And it’s been working rather good I must say. What I thought. Found out now that – at least since SP2 – we’ve had serious troubles sending to mail servers using grey listning. funny… One fix is to add a batch script restarting smtp server every day (forcing it to resend the queued mail). I gave up and added a smarthost instead and now I rely on my broadband provider.
So now I’m waiting for people to start reacting on my old mails finally delivered. Wooho. 
For anyone else forced to play exchange-guru on your own due to costs or whatever.. this is what I did:
- Added a scheduled batch script restarting the smtp server
net stop smtpsvc
net start smtpsvc - Added a non-existing registry key:
HKLM\System\CurrentControlSet\Services\SMTPSVC\Queuing\
“GlitchRetrySeconds” – DWORD set to 300. - Added my broadband providers smtp server as a smarthost in Exchange following http://www.arrowmail.co.uk/howto/smrthost.aspx
Hope helps someone else. Now back to real work. Back to my PHP code, away from Exchange, away from Windows server..