Permanent Error 554: Relay Access Denied

Question

I am encountering the infamous SMTP Error 554: Permanent Error: Ralay Access Denied when attempting to send SMTP messages to external domains. I have requested assistance from our network administrator who manages our SMTP server, but was curious if there was something that could be done via my PL/SQL procedure to avoid this error? Any assistance would be greatly appreciated.

Answer 1

There is no trust involved if you are sending email to a recipient in the SMTP server's domain (or, more accurately, it is an entirely different and much lower hurdle to clear) than if you are trying to send mail outside the domain.
Think of it this way. A SMTP server gets a request from a host it knows nothing about indicating that it wants to send an email to a recipient in the server's domain. Since the SMTP server has no idea whether this is some other company's legitimate email server or a spammer's server, and since there is no practical way to white list every SMTP server that might send inbound email to a domain, and since the SMTP server isn't vouching for the identity of the sender, it just passes the email along to the recipient. If that same server gets a request to relay a message from an unknown host to some other organization's SMTP servers, however, it has a completely different behavior. Since the organization does have a reasonably practical way of specifying the set of servers that can send mail, and since relaying an email does (in today's world) imply a level of trust that the message is legitimate, the SMTP server would, and should, block the database server from sending external emails. Unless and until, of course, the SMTP admin goes in and explicitly trusts the database server.
Justin