fix: update interface detection code to support additional interfaces Docker adds.

debian-package/debian/changelog

@@ -1,3 +1,12 @@
+vpn-router (0.3.1-1) unstable; urgency=medium
+
+  * Ignore virtual interfaces when mode auto looks for the internal
+    interface. The Docker bridge docker0, which has an address, was counted
+    as a second internal interface, so vpn-router-setup and
+    vpn-router-docker failed on a host with Docker installed.
+
+ -- Sławomir Koszewski <slawek@koszewscy.waw.pl>  Fri, 23 Oct 2026 13:44:00 +0200
+
 vpn-router (0.3.0-1) unstable; urgency=medium
 
   * Secure the ports Docker publishes. Rules in a chain of their own,