DOC-3595 RS: Prevent dnsmasq from using port 53

Author: rrelledge

content/embeds/port-53.md

@@ -1,7 +1,9 @@
-If port 53 is in use, the installation fails. This issue can occur in default installations of certain operating systems in which `systemd-resolved` (DNS server) is running.
+If port 53 is in use, the installation fails. This issue can occur in default installations of certain operating systems in which `systemd-resolved` (DNS server) or `dnsmasq` is running.
 
 To prevent this issue, change the system configuration to make this port available before installation.
 
+To prevent `systemd-resolved` from using port 53:
+
 1. Edit `/etc/systemd/resolved.conf`: 
 
     ```sh
@@ -31,3 +33,29 @@ You might encounter a temporary name resolution error (`sudo: unable to resolve
     ```sh
     sudo service systemd-resolved restart
     ```
+
+To prevent `dnsmasq` from using port 53:
+
+1. Stop the `dnsmasq` service if it's running:
+
+    ```sh
+    sudo systemctl stop dnsmasq
+    ```
+
+1. Prevent `dnsmasq` from starting automatically at system boot:
+
+    ```sh
+    sudo systemctl disable dnsmasq
+    ```
+
+1. Mask `dnsmasq` to prevent it from being started manually or by other services:
+
+    ```sh
+    sudo systemctl mask dnsmasq
+    ```
+
+1. Verify `dnsmasq` is no longer active and won't start at system boot:
+
+    ```sh
+    sudo systemctl status dnsmasq
+    ```