Configuring hostname for HELO command in SMTP with free plugin "Mail Server"

brainchild

How may the hostname, as used in the SMTP command HELO, sent by postfix, be configured through the free plug-in Mail Server?

Ideally, such a value could be configured independently for each mail domain.

Alternatively, the value could be taken as the FQDN configured for the domain associated with the mail user account invoked to process the outgoing message, based on the credential supplied by the SMTP client.

At the moment, the value appears to be taken from the first section of machine-wide domain name, registered by the kernel, without the suffixes of the FQDN.

Such behavior is leading to rejection by many mail servers, largely as among the methods being used to block spam.

See log entry below.

I have upgraded to the most recent release of the Mail Server, version 5.6. The installed release of aaPanel is also up to date, as version 7.0.13. The system is CentOS Linux 7, architecture x86_64, with all packages kept updated.

<timestamp> <myhostname> postfix/smtp[28136]: 21DC35591: to=<user@example.org>, relay=mail.example.org[11.22.33.44]:25, delay=7.3, delays=0.27/0.01/6.8/0.27, dsn=5.5.2, status=bounced (host mail.example.org[11.22.33.44] said: 504 5.5.2 <myhostname>: Helo command rejected: need fully-qualified hostname (in reply to RCPT TO command))

aaP_demo1

brainchild
Has your server's hostname changed to a FQDN required by Mail Server?
To change your hostname to a FQDN:
sudo hostnamectl set-hostname [Fully Qualified Domain Name]

brainchild

aaP_demo1

A FQDN has been set with the system command hostname.

Ideally, of course, the mail server could be configured with a domain name separate from the domain name configured for the system. In fact, the stronger ideal is that the domain used for SMTP would correspond to the account being used for login by the SMTP client, since virtual domains are supported for sending and receiving mail.

aaPanel_Kern

Hello, is it possible to modify it in the configuration file?

brainchild

aaPanel_Kern

If the configuration is regenerated by the user action Repair, then the configuration file shows the up-to-date name for the value of myhostname.

Overall, the design is quite weak.

aaPanel_Kern

Hello, the default host name is used and it is running normally. Why do you need to click Repair?

brainchild

aaPanel_Kern

The configuration file had shown a hostname previously set, which was not the current hostname or a valid FQDN.

The system hostname had been changed, but the mail server was using an old value, embedded the configuration file. I assume the file had been automatically generated before the current hostname was properly set for the system.

Regardless, administrators should have flexibility to determine the hostname, whether as one dynamically resolved from the system, or as one chosen specifically for SMTP.