Question : Exchnage server 2003 mail issue

Issue 1
We have Windows 2kas running Exchange 2003. On a particular inhouse user, someone(outside our domain) tried sending them an email and wasn't able to. The sender got an error message that read:

Final-Reciepient:rfc822; [email protected]
action: failed
Status: 5.0.0
Diagnostic-Code: x-postfix; host mailserver.domainname.com [public ip address] said:
552 Requested mail action aborted: exceeded storage allocation (in reply to MAIL FROM command)

I have no storage limits set. All of the limits are set to windows default. Could it be that they reached the default limit? If so what is the default limit?

Issue 2
On same server, i noticed that on the queue there are specific domains that are sitting there as retrys. When i click on them i get in the information box:
Unable to bind to destination server in DNS

I contacted my ISP and confirmed that the completed the reserve lookup to the specific public ip address of the mail server and the tell me that it wasn't totally done. Meaning that if you do an nslookup by ip address you don't get my server name, yet their destinations.. But if you do nslookup by server name you do get the correct public ip address.. Would this have anything to do with my mail issue?

Any suggestions is greatly appreciated...

Answer : Exchnage server 2003 mail issue

Ah ha.
The sending domain has a PIX. That could still be the cause of the problems.
If they cannot be persuaded to remove the mailguard feature, it will have to be an SMTP Connector for that domain to route through your ISP.

Simon.