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# How To Fix Apache Configuration Error AH00558: Could not reliably determine the server's fully qualified domain name.
- URL: https://snubmonkey.com/how-to-fix-apache-configuration-error-ah00558-could-not-reliably-determine-the-servers-fully-qualified-domain-name/
- Published: 2024-01-23T06:01:46.000Z
- Updated: 2025-04-16T22:29:45.000Z
- Description: This is the seventeenth in a series of posts, featuring Protips, tips, tricks, hacks, and secrets provided by Our Team 🙊 — We want to share our top tips for the growing and thriving Linux community out there. Because sometimes you need a little help...
- Author: yannick Coffi
- Tags: tips

> *An Apache AH00558: Could not reliably determine the server's fully qualified domain name message occurs when Apache is not configured with a global ServerName directive. The warning is only informative yet annoying, and will in any case prevent Apache from operating normally.*

  
### Troubleshooting using `systemctl`

###   

The first step in dealing with the AH00558 problem is to use `systemctl` to verify Apache's status. The output contains all of the information required to help us resolve the issue.

Let's run the following to check Apache’s status:

```
$ sudo systemctl status apache2.service -l --no-pager
```

The `-l` option tells `systemctl` to output the complete line, rather than using ellipses (…) for long lines.   
  
The `--no-pager` flag will output the complete log to your screen without using a program like `less`, which only exposes one screen of material at a time.

The output should be similar to the following:

```
Output

● apache2.service - The Apache HTTP Server
   Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
  Drop-In: /lib/systemd/system/apache2.service.d
           └─apache2-systemd.conf
   Active: active (running) since Mon 2024-01-22 14:54:23 UTC; 7h ago
  Process: 1814 ExecStart=/usr/sbin/apachectl start (code=exited, status=0/SUCCESS)
 Main PID: 46 (apache2)
    Tasks: 55 (limit: 2750)
   CGroup: /system.slice/apache2.service
           ├─46 /usr/sbin/apache2 -k start
           ├─47 /usr/sbin/apache2 -k start
           └─48 /usr/sbin/apache2 -k start

Jan 22 14:54:23 43d2cd344s1 systemd[1]: Starting The Apache HTTP Server...
Jan 22 14:54:23 43d2cd344s1 apachectl[35]: AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message
Jan 22 14:54:23 43d2cd344s1 systemd[1]: Started The Apache HTTP Server.

```

###   
  
Troubleshooting using `apachectl`

###   

The `apachectl configtest` command inspects the syntax of Apache configuration files. It also checks the files that it recursively points to.

Let's run the following command:

```
$ sudo apachectl configtest
```

The output should be similar to the following:

```
Output

AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 121.0.0.1. Set the 'ServerName' directive globally to suppress this message

Syntax OK
```

  
Generally speaking, it alerts you that Apache could not identify a valid ServerName directive in its configuration file; nothing more, nothing less.

###   
  
Setting a Global ServerName Directive

###   

To overcome this issue, we need to add a ServerName directive to our Apache configuration. To manage requests for numerous sites on a single server, Apache employs the ServerName directive to translate incoming HTTP requests to an IP address or DNS hostname, which is then handled by VirtualHost directives.  
  
Let's open the `/etc/apache2/apache2.conf` file with root privileges with our preferred text editor here; nano.

```
$ sudo nano /etc/apache2/apache2.conf

```

  
Add a line containing ServerName 127.0.0.1 to the end of the file:

```
. . .
. .
.
 
# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

ServerName 127.0.0.1

```

  
Run `apachectl` to test that the configuration is valid.

```
$ sudo apachectl configtest

Output
Syntax OK
```

  
Now, let's reload Apache’s configuration and check its status using `systemctl reload` along with `systemctl status` command:

```
$ sudo systemctl reload apache2 && sudo systemctl status apache2

Output

● apache2.service - The Apache HTTP Server
     Loaded: loaded (/lib/systemd/system/apache2.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2024-01-22 14:54:23 UTC; 7h ago
       Docs: https://httpd.apache.org/docs/2.4/
    Process: 9025 ExecReload=/usr/sbin/apachectl graceful (code=exited, status=0/SUCCESS)
   Main PID: 1814 (apache2)
      Tasks: 56 (limit: 2750)
     Memory: 6.4M
        CPU: 2.574s
     CGroup: /system.slice/apache2.service
             ├─1814 /usr/sbin/apache2 -k start
             ├─9030 /usr/sbin/apache2 -k start
             └─9031 /usr/sbin/apache2 -k start

Jan 22 14:54:23 virtuallinux systemd[1]: Starting The Apache HTTP Server...
Jan 22 14:54:23 virtuallinux systemd[1]: Started The Apache HTTP Server.
Jan 22 14:54:25 virtuallinux systemd[1]: Reloading The Apache HTTP Server...
Jan 22 14:54:25 virtuallinux systemd[1]: Reloaded The Apache HTTP Server.
Jan 22 22:53:45 virtuallinux systemd[1]: Reloading The Apache HTTP Server...
Jan 22 22:53:45 virtuallinux systemd[1]: Reloaded The Apache HTTP Server.
```

Again, while this annoying message does not prevent Apache from running, it can be resolved by setting a global ServerName directive.  
  
We hope this was of great use!