Troubleshooting `Unable to connect to remote asterisk (does /var/run/asterisk/asterisk.ctl exist?)`

This error message indicates that the Asterisk CLI (command-line interface) cannot connect to the running Asterisk daemon. This can happen for several reasons. Here's a guide to help you troubleshoot and resolve the issue:

1. Understand the Context:

Are you trying to start Asterisk? This error message appears when using asterisk -r without first starting the Asterisk daemon itself. You should use asterisk -vvvv or your system's init script to launch Asterisk.
Are you trying to connect to a running Asterisk? If Asterisk is already running, then continue with the troubleshooting steps below.

2. Check Asterisk Status:

Use the following command to check if Asterisk is running:
```
systemctl status asterisk
```
If Asterisk is not running, start it using:
```
systemctl start asterisk
```
If Asterisk is running but the error persists, proceed to the next steps.

3. Verify File Existence:

The error message specifically asks about the existence of /var/run/asterisk/asterisk.ctl. This file is created when Asterisk starts and serves as the communication channel between the CLI and the daemon.
Use the following command to check if the file exists:
```
ls /var/run/asterisk/asterisk.ctl
```
If the file is missing, it indicates that Asterisk might not be running properly. Refer to Asterisk logs for further details.

4. Check Permissions:

Ensure that the user attempting to connect to the CLI has permission to access the /var/run/asterisk/asterisk.ctl file.
Use the following command to check permissions:
```
ls -l /var/run/asterisk/asterisk.ctl
```
If the user lacks appropriate permissions, adjust ownership or group accordingly.

5. Additional Considerations:

SELinux: If SELinux is enabled, it might be blocking access to the control file. Check SELinux logs for related entries and adjust the policy if necessary.
Systemd Service File: Review the systemd service file for Asterisk (/usr/lib/systemd/system/asterisk.service) and ensure it's configured correctly.

If you've gone through these steps and the issue persists, it's recommended to consult the Asterisk documentation or community forums for further assistance. Provide details about your specific setup, version, and any additional error messages encountered.

Further reading: Asterisk: The Definitive Guide: Open Source Telephony for the Enterprise