530 5.7.3 Client was not authenticated

[tyin123]

Hi, we have two MS Exchange 2003 Servers in FE/BE setup.
Now, we got "530 5.7.3 Client was not authenticated " error when outside domain tried to send emails to us. I tried to send email mannualy by using telent port 25, it was the same. The virtual SMTP server on front end is set for allowing anomymous access.

Thanks in advance for any recommendations.

 

[harpert]

It is a BAD manner of operation to allow anonymous access. This causes your Exchange server to be open for SPAM
By default the Exchange server allows anonymous entry to anyone who wants to sent email to EXISTING users within it's domain.

For example when my domainname is: company2.com and you use a non domain computer with an IP sddress OUTSIDE your domain, you are still able to send email (using a simple email client like Outlook express) to send email to users WITHIN the domain.
However if Exchange discovers that the mail is meant for someone OUTSIDE the domain (so other than xxx.mycompany2.com) it answers NO ANONYMOUS ACCESS

This behaviour is default and GOOD because this prevents from RELAYING and thus spamming using your server.

If you make a TRUSTED relation between the two servers, also mail to the other server (even with another domainname) will be accepted from any source.

Harpert