509 HELO/EHLO was syntactically invalid

I have a problem where my server is refused connection to another SMTP server because of its name. The name, dom_svr_2, has illegal characters in it.

The error is the following:

509 HELO/EHLO was syntactically invalid (dom_svr_2.mydomain.com). Check your configuration.

Is there a way I can have my server identify itself to other SMTP server using one name, for example mail.mydomain.com, and still retain its existing name on my internal network?

Subject: 509 HELO/EHLO was syntactically invalid

Yes, you have to register a Canonical Name Record (CNAME) on DNS.

ST

Subject: 509 HELO/EHLO was syntactically invalid

try this;

server configuration document

basics tab

fully qualified internet host name

set it to be what you want in the helo (what your dns a entry is), eg myhostname.mydomain.com

you can test if it’s working by unloading and loading the router task, it should display something like this;

Internet SMTP host myhostname in domain mydomain.com