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In certain cases, updating the macOS Roaming Client from v1.x.x to v2.x.x does not restore the original DNS settings, leaving the DNSFilter loopback address 127.0.0.1 as the device's DNS configuration.

This happens when the v1.x.x agent crashes, is force-quit, or the device restarts before the agent can restore the saved DNS settings.

When the device updates to v2.2.0+ from an affected installation, it can lose network connectivity until the correct DNS settings are restored manually.

✍️ Version 2.2.0+ uses a macOS System Extension and no longer modifies the device's DNS settings directly, so this issue does not occur once updated. Devices already affected require manual correction.

What we know

• Prior to v2.2.0, the agent directly controlled the system DNS configuration and could set it to 127.0.0.1 to route queries locally through the agent. This was part of normal agent startup and network connection
• On a clean shutdown, the agent restores DNS automatically. When the proxy activates, the agent saves each network service's existing DNS configuration in memory; when the proxy deactivates, the agent restores each service to its prior settings, or to the DNS provided by DHCP
• The saved DNS settings exist only in memory. If the agent crashes, is force-quit, or the device is hard-rebooted during the update, the in-memory data is lost before the restore can run, and DNS remains set to 127.0.0.1
• The uninstall script has no separate DNS restoration step. It relies on the agent's clean shutdown to restore DNS

How to work around the issue

While DNS is stuck at 127.0.0.1 and the v1.x.x agent is no longer running, the device has no internet access. Restore DNS first to regain connectivity. Removing the stuck 127.0.0.1 entry returns macOS to the DNS assigned automatically by the network through DHCP, which is the correct fix.

Restore DNS from Terminal

Run this command, replacing Wi-Fi with the active network service name if the device uses a different interface:

sudo networksetup -setdnsservers Wi-Fi empty

The empty argument restores the interface to the DNS provided by DHCP, the same action the agent performs internally on a clean shutdown.

To list the available network service names:

networksetup -listallnetworkservices

Restore DNS from System Settings

1. From the device, navigate to System Settings and select Wi-Fi
2. Select Details for the connected Wi-Fi network 
   
3. Select the DNS tab. The DNSFilter loopback address 127.0.0.1 appears under DNS Servers
4. Select the 127.0.0.1 entry, then select the minus (➖) icon to remove it
   
5. Leave DNS Servers empty and select OK to save 
   

Removing the entry returns the device to automatic DNS and restores connectivity.

✍️ If the device has no DHCP-provided DNS and still cannot resolve names, a public DNS server such as 8.8.8.8 can be added under DNS Servers as a temporary fallback. Restoring automatic DNS remains the correct fix.

After connectivity is restored, the Support team may request diagnostic logs to investigate the root cause. Collecting logs is optional and is not required to resolve the issue.