Nick Howitt wrote:
Yes but the manual (?) entry in master.cf was overriding the parameter in main.cf which ClearOS had set correctly. This stopped the ClearOS change from taking effect.

Ah yes, good catch.

Peter Baldwin wrote:
Changing the Mail Hostname parameter in the SMTP Server app should have done the trick.

Yes but the manual (?) entry in master.cf was overriding the parameter in main.cf which ClearOS had set correctly. This stopped the ClearOS change from taking effect.

Hi Drew and Nick,

Changing the Mail Hostname parameter in the SMTP Server app should have done the trick. That webconfig element maps to the myhostname parameter in /etc/postfix/main.cf. By default, this is set to the same hostname specified in the first boot installation wizard, but this can be changed in the SMTP Server app later on. Some administrators like their SMTP banner replying with something like "mail.example.com" instead of the generic hostname.

I am very sketchy on mail, but I think the existence of a PTR record is the primary concern and not its contents! The fact that it exists allows it to pass certain validation checks, e.g. reject_unknown_client as one of the checks in main.cf (which I don't use)

In main.cf I am not sure why you have the smtp line like that. I believe the "-o ....." is used to overwrite the main.cf parameter, so in your case you are not permitting postfix from picking up "mydomain" from main.cf.

My equivalent line in master.cf is:

# ==========================================================================

# service type  private unpriv  chroot  wakeup  maxproc command + args

#               (yes)   (yes)   (yes)   (never) (100)

# ==========================================================================

smtp      inet  n       -       n       -       -       smtpd

...... and it looks so much better on the forum, when you put it between "code" tags. Then everything lines up beautifully.

Nick,

I found it! Instead of looking in main.cf, I looked in master.cf. There was a line:

# ==========================================================================
# service type private unpriv chroot wakeup maxproc command + args
# (yes) (yes) (yes) (never) (100)
# ==========================================================================
smtp inet n - n - - smtpd -o myhostname=mail.mydomain.com

and it was still set to AT&T's internal ptr for their name for the IP. I changed it to my domain name and has the new ISP set a PTR, and I think it is normal now. We shall see if I get any more rejections.

MX Toolbox is still reporting this warning, though:

Reverse DNS Mismatch Reverse DNS does not contain the hostname

So I don't know what detail has it concerned. PTR does now report to mail.mydomain.com

Thanks,
Drew

Do you have a ptr record set on your domain?

Hi Nick,

I am afraid not...that ISP wouldn't even give me a SMTP to use. I'm not relaying through anyone (as far as I know!) I'm stumped as to where it gets the information - it is as if it stored it from before I switched...

73,
Drew

Have you by an chance got an outbound SMTP relay via your old ISP still set up?