How to Fix a Postfix MyHosting Config Problem on Ubuntu

Discover a step-by-step guide to resolve the `myhostname` configuration issue in Postfix on Ubuntu. Learn how to edit your Postfix settings for a successful mail server setup.
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This video is based on the question https://stackoverflow.com/q/56612459/ asked by the user 'user3821102' ( https://stackoverflow.com/u/3821102/ ) and on the answer https://stackoverflow.com/a/69076199/ provided by the user 'js123456789js' ( https://stackoverflow.com/u/16572111/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Fix a Postfix MyHosting Config Problem on Ubuntu

Setting up a mail server can be both exciting and challenging, especially when dealing with configuration issues. One common problem users encounter relates to the myhostname setting in the Postfix mail transfer agent (MTA). This guide will walk you through the resolution of a myhostname config problem on Ubuntu, specifically if you’ve encountered the error message:

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Understanding the Problem

You've attempted to install Postfix with local mail configuration, but you’re facing an issue with what is likely an incorrectly formatted hostname. The error message indicates that your hostname contains a misplaced delimiter (in this case, too many dots in the hostname). This can prevent the installation from being completed successfully.

The first step to resolving this issue is to ensure your myhostname entry in the Postfix configuration file is correctly formatted.

Solution Overview

Fortunately, fixing this issue requires only a few steps involving the editing of the Postfix's main configuration file, /etc/postfix/main.cf. The solution detailed below applies to Ubuntu 20.04.

Step 1: Check Your Current Configuration

First, you need to see what value is currently set for myhostname. You can do this using the cat command followed by grep.

Open your terminal.

Run the following command:

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Step 2: Edit the Configuration File

If you see a value like myusername..name, this means there’s an error in how the hostname is defined. You need to modify it to a correctly formatted string—ideally, something like myusername.name.

Open the configuration file with the vi editor (you can use any text editor you prefer, but here we will use vi):

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Look for the line starting with myhostname = and change it to a valid hostname. For example:

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Step 3: Verify the Changes

To confirm that you’ve made the correct changes, run the cat command again:

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You should now see your updated hostname:

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Conclusion

After updating your myhostname configuration in the /etc/postfix/main.cf file, you should no longer encounter the error when running newaliases. This small fix ensures that your Postfix installation can proceed successfully.

If you continue to experience problems, it might be worth checking other configurations or referring to the Postfix documentation for further troubleshooting. Happy mailing!