From 8ed4e0a8d80ac6fe8fc3c2e9bf7eeebef37f313c Mon Sep 17 00:00:00 2001
From: Kananek Thongkam <info.dvgamer@gmail.com>
Date: Sun, 19 Jan 2025 21:12:05 +0700
Subject: [PATCH] feat: add guide for disabling DHCP on macOS to resolve port
 conflicts

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+---
+layout: ../../layouts/Layout.astro
+title: 'Disabling DHCP on macOS: A Step-by-Step Guide'
+pubDate: 2025-01-19
+description: 'Learn how to disable the built-in DHCP service on macOS to avoid port conflicts.'
+author: 'Kananek T.'
+image:
+  url: 'https://docs.astro.build/assets/rose.webp'
+tags: ["macOS", "DHCP", "networking"]
+---
+# Disabling DHCP on macOS: A Step-by-Step Guide
+
+If you encounter issues such as port conflicts when running a DHCP server on macOS, you might need to disable the built-in DHCP service. This guide walks you through the process of disabling DHCP using the `bootpd.plist` configuration file.
+
+---
+
+## Symptoms of DHCP Conflicts
+
+An example error message might look like this:
+
+```
+Error: control/dhcp/set_config 
+enabling dhcp: starting dhcp server: dhcpv4:
+creating ipv4 udp connection: cannot bind to port 67: address already in use
+```
+
+This indicates that another process is already using port 67, which is reserved for DHCP.
+
+---
+
+## Steps to Disable DHCP on macOS
+
+### 1. **Locate and Edit Configuration File**
+
+Open Terminal and edit the `bootpd.plist` file located in `/etc/`:
+
+```bash
+sudo nano /etc/bootpd.plist
+```
+
+### 2. **Modify DHCP Settings**
+
+- **Disable DHCP**:
+  Locate the `<key>dhcp_enabled</key>` section and set its value to an empty `<array>`:
+  ```xml
+  <key>dhcp_enabled</key>
+  <array/>
+  ```
+
+- **Remove or Disable Subnets**:
+  If there is a `<key>Subnets</key>` section, comment it out or remove the `<dict>` entirely.
+
+- **Disable BOOTP**:
+  Ensure the following key is set to `false`:
+  ```xml
+  <key>bootp_enabled</key>
+  <false/>
+  ```
+
+### 3. **Save and Exit**
+
+Press `Ctrl + O` to save changes, then `Ctrl + X` to exit the editor.
+
+---
+
+### 4. **Restart Networking Services**
+
+Restart the `bootpd` service to apply the changes:
+
+```bash
+sudo launchctl stop com.apple.bootpd
+sudo launchctl unload /System/Library/LaunchDaemons/bootps.plist
+```
+
+This stops the DHCP service from running.
+
+### 5. **Verify Changes**
+
+Check if port 67 is still in use:
+
+```bash
+sudo lsof -i :67
+```
+
+If no output appears, the DHCP service has been successfully disabled.
+
+---
+
+## Troubleshooting
+
+### Port Still in Use?
+- Use the following command to identify processes using port 67:
+  ```bash
+  sudo lsof -i :67
+  ```
+- Stop the process:
+  ```bash
+  sudo kill -9 <PID>
+  ```
+
+### Restore Defaults
+If needed, restore the original configuration:
+
+```bash
+sudo cp /etc/bootpd.plist /etc/bootpd.plist.bak
+sudo defaults write /etc/bootpd.plist ""
+```
+
+---
+
+By following this guide, you can successfully disable DHCP on macOS, resolve port conflicts, and ensure your network services run smoothly.
+