Question : Exchange 2003 Relay problems

Hi,

I'm recently managing a very chaotic network, because a virus entered the system that was unprotected and now i have a exchange server relaying mails to the internet and now the domain and public IP were put in the blacklist of several servers.

After searching the internet for solutions and after installing a corporated antivirus solution in all computers  and making some changes to the exchange configuration i think the out going spam bombarding the net seems to be solved but i now that the problem is not completely gone because opening the events viewer i still get logs of an event saying :This is an SMTP protocol warning log for virtual server ID 1, connection #xx. The remote host "xxx.xxx.xxx.xxx", responded to the SMTP command "mail" with "453 #4.1.8 Domain of sender address <[email protected]> does not exist  ". The full command sent was "MAIL FROM:<[email protected]> ".  This may cause the connection to fail.
This is the example and this event keeps showing every second for hour and hours filling up the event list. I saw some solutions on the internet saying it must be a mail bombing OK but still no solution I even searched the experts-exchange and the solution found did not solve my problem i URGENTLY need to solve this issue please help.

Answer : Exchange 2003 Relay problems

The VB.NET class needs to be in a compiled assembly, and be registered as COM. To make the .NET assembly COM visible, in VS IDE, right click on the project in Solution Explorer, then press Properties, click on Application tab, then Assembly Information button, check Make assembly COM-Visible. Then compile the assembly.
To register an existing assembly as COM, use regasm.exe [Assembly Name] in Command prompt.