I have 2 questions which may be related.
I am using Exchange 2000 on MS 2000 Server. The outbound mail is set to goto BT's smarthost (smtp.btconnect.com). The inbound mail path is a bit more complex. It first gets collected in a catchall BT pop mailbox, This is picked up by a third party pop collector and passed onto SurfControl (spam filter) which then removes the rubbish and forwards the mail onto the exchange server. The mail is then sorted to the relevant mailboxes.
The mail server has no routable IP address. It has a 192 internal address only. The pop collector is on a different server to the exchange and surfcontrol programs.
When a message comes in to certain mailboxes, they are forwarded to an external address. For some reason, these forwarded (copied) mails do not get sent but end up in the admin box as a non deliverable.
Some emails get sent to the admin mailbox as non deliverable but the message appears to be addressed correctly. Even if there are no CC's on the mail it can still happen. The mailbox recieved most messages with any problem but there are at least 2 or 3 account that regularly do not recieve a (what seems to be) properly formatted message to the correct address.
Any pointers about where things are going wrong would be greatly appreciated.