I am new to this organization and am trying to solvea problem. Unfortunately I have no previous systems information to go on... This is Exchange on SBS 2003. Some but not all messages are timing out in the queue with the following errors: #4.4.7; #5.5.0; #5.7.1; #5.4.6.... There are at lease some domains where no messages get through. In the queues I see lots of virtual smtp connectors for various domains, some valid customers and some such as doubleclick.net. Is this normal?

I'll clarify this and add some info in hopes of getting some insight! What I see isnot lots of virtual smtp connectors- I meant to say I see lots of queues recipient domains in the queue list. I'm working with one problem domain in particular- e-mails sent to this one just hang in the queue for 2 days, then may or may not deliver. I can nslookup this domain okay and can telnet into that mail server on port 25.... Any suggestions? Another question: In this servers DNS server there are lots of root hint servers built. Are these necessary? what are they used for? Thanks for any help!

it sound like you aredoing dns lookup to send outbound mail, so exchange trys to send mail directly to the reciepents mail server. some mailserver wont accept mails from any server, try seting all mail to go through you ISP.