[BlueOnyx:24509] Re: Problem with "Accept from unresolvable domains"

[Lew Berry]

Lew wrote:
> I don’t think it’s a problem with the email address, that comes much later in the process after HELO.
> It’s wanting the full hostname (FQDN of the root, ie ns1.mydomain.net) of the box itself to do a PTR lookup etc..

M Aronoff wrote:
>If it is not looking at the email address I am confused even more by this setting. So how are clients supposed to configure Outlook to be able to send email?

Not really an issue with email client, it has to do with how email servers negotiate a session between them.
Session (simple version) looks like this:
S: 220 smtp.server.com Simple Mail Transfer Service Ready
C: HELO client.example.com
S: 250 Hello client.example.com
C: MAIL FROM:<mail at samlogic.com>
S: 250 OK
C: RCPT TO:<john at mail.com>
S: 250 OK
C: DATA
S: 354 Send message content; end with <CRLF>.<CRLF>
C: <The message data (body text, subject, e-mail header, attachments etc) is sent>
C: .
S: 250 OK, message accepted for delivery: queued as 12345
C: QUIT
S: 221 Bye

You’re not getting to MAIL FROM command, the mail server is looking for the valid hostname with FQDN from your server.

telnet to port 25 of your mailserver and see what the 220 returns (that’s how it will answer the connection request). That’s also the name it presents to other mailservers, with BX it’s usually the root name of the box. If it’s correct you may want to look at DNS issues resolving that name or SPF and/or DMARC issues.
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