Installing Plesk fails with error: postconf: warning: valid_hostname: numeric hostname: 212

Vincent Lauton

Updated July 11, 2024 21:29

Plesk for Linux kb: technical

Symptoms

When using the Plesk installer script on a fresh server, it fails with:

postconf: warning: valid_hostname: numeric hostname: 212postconf: fatal: unable to use my own hostnamepostconf: warning: valid_hostname: numeric hostname: 212postconf: fatal: unable to use my own hostnamedpkg: error processing package postfix (--configure):installed postfix package post-installation script subprocess returned error exit status 1Errors were encountered while processing:postfixneedrestart is being skipped since dpkg has failedE: Sub-process /usr/bin/dpkg returned an error code (1)

Setting up postfix (3.4.13-0ubuntu1.4) ...

Postfix (main.cf) configuration was untouched. If you need to make changes, edit /etc/postfix/main.cf (and others) as needed. To view Postfix configuration values, see postconf(1).

After modifying main.cf, be sure to run 'systemctl reload postfix'.

Running newaliases
newaliases: warning: valid_hostname: numeric hostname: 203.0.113.2
newaliases: fatal: file /etc/postfix/main.cf: parameter mydomain: bad parameter value: 203.0.113.2
dpkg: error processing package postfix (--configure):
installed postfix package post-installation script subprocess returned error exit status 75
..........
Errors were encountered while processing:
postfix
E: Sub-process /usr/bin/dpkg returned an error code (1)
Launching component and product checkers...
Downloading file report-update: 100% was finished.
Downloading file pool/PSA_18.0.62_14908/examiners/py_launcher.sh: 100% was finished.

ERROR: An error occurred on attempt to install packages.
Attention! Your software might be inoperable.
Visit https://support.plesk.com/ to search for a solution.

Cause

The system hostname only cointains numbers, or ends with numbers.

Resolution

Use valid characters for hostnames as ASCII(7) letters from a to z, and digits from 0 to 9; not numbers only. It is recommended to use a Fully Qualified Domain Name (FQDN) as the hostname. To change it apply one of the following solutions:

In Plesk interface

Log in to Plesk
Go to the menu Tools & Settings > Server Settings, specify the new hostname in the field Full hostname and click OK at the bottom of the page to apply the changes:

Via CLI (Linux only)

Connect to the server via SSH.
execute the following command with preferred hostname value instead of host.example.com:

# plesk bin server_pref --update -hostname host.example.com
Restart services sw-cp-server and sw-engine:

# systemctl restart sw-cp-server && systemctl restart sw-engine

It may be also necessary to change parameters myhostname and mydestination in /etc/postfix/main.cf, move out/remove /var/parallels/autoinstaller-installation-failure.flag and run plesk repair installation in case Plesk Installer thinks that Plesk is already installed.