SMTP Telnet Test

We are standing up a new data center and users received SMTP errors while testing. We were able to ping the server so DNS lookup and network traffic was working. But we only had a generic SMTP error message. So, I fired up telnet and tested our SMTP connection using these commands:

Test Email

When we first tested send emails through the SMTP server, we received an “Unable to relay for” error. That’s much more descriptive and a useful message to send to the Exchange administrators.

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