Solving Sequoia Split DNS Lookup Issue on macOS System

Solving Sequoia Split-DNS Lookup Issue on macOS System

In this article, we will cover the Sequoia split-DNS lookup issue on macOS systems. This problem can affect users who have a local DNS server, such as a Synology NAS, and want to resolve private IP addresses instead of public ones. We will discuss the key concepts involved, provide subtitles, and use proper formatting for code blocks and paragraphs.

Understanding Split-DNS Lookup on macOS

Split-DNS lookup, also known as split-horizon DNS, is a method of resolving domain names to different IP addresses based on the network location of the requesting client. By default, macOS does not support split-DNS, and it relies on a single DNS server for both private and public DNS resolution.

The Sequoia Issue

Sequoia is an open-source tool that allows users to override default DNS settings on macOS systems. However, it may face issues when resolving domain names to private IP addresses, particularly when the local DNS server does not support EDNS0 packets.

Troubleshooting the Sequoia Split-DNS Lookup Issue

To troubleshoot the Sequoia split-DNS lookup issue on macOS systems, follow these steps:

1. Check if the local DNS server supports EDNS0 packets.
2. If it does not, modify the Sequoia configuration to disable EDNS0 packets.
3. Add the local DNS server to the system's DNS settings.
4. Modify the system's hosts file to point the affected domains to the private IP addresses.

Modifying Sequoia Configuration

To modify the Sequoia configuration, follow these steps:

1. Stop the Sequoia daemon:

$ sudo launchctl unload /Library/LaunchDaemons/org.macports.sequoia.plist

2. Edit the Sequoia configuration file:

$ sudo nano /opt/local/etc/sequoia/sequoia.conf

3. Add the following line to the configuration file:

edns0 = off

4. Restart the Sequoia daemon:

$ sudo launchctl load /Library/LaunchDaemons/org.macports.sequoia.plist

Modifying the System's Hosts File

To modify the system's hosts file, follow these steps:

1. Edit the hosts file:

$ sudo nano /private/etc/hosts

2. Add the following line to the hosts file:

[domain] [private IP]

3. Replace [domain] with the affected domain name and [private IP] with the private IP address of the affected domain.

• The Sequoia split-DNS lookup issue on macOS systems can occur when the local DNS server does not support EDNS0 packets.
• To resolve the issue, modify the Sequoia configuration to disable EDNS0 packets, add the local DNS server to the system's DNS settings, and modify the system's hosts file to point the affected domains to the private IP addresses.

References

• Books:

  • Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson Education, Inc.

• Online Resources:

  • Sequoia on GitHub
  • Synology DDNS Documentation
  • ServerFault Discussion