diff --git a/src/opengnsys/modules/server/OpenGnSys/__init__.py b/src/opengnsys/modules/server/OpenGnSys/__init__.py
index 765bb5a..1203eb2 100644
--- a/src/opengnsys/modules/server/OpenGnSys/__init__.py
+++ b/src/opengnsys/modules/server/OpenGnSys/__init__.py
@@ -34,6 +34,7 @@ import base64
 import os
 import random
 import shutil
+import socket
 import string
 import sys
 import threading
@@ -142,6 +143,36 @@ class OpenGnSysWorker(ServerWorker):
                     logger.info('Connection to ogcore restored, re-registering')
                     self._send_started()
 
+    def _best_interface(self, nets):
+        """
+        Return the interface whose IP the OS routing table would use to reach
+        ogcore, by opening a no-op UDP socket (no packets sent) and reading
+        the local address assigned by the kernel.
+
+        Returns None if the routing query itself fails (network not ready yet),
+        so the caller keeps retrying. Falls back to nets[0] only when the query
+        succeeds but no interface matches the routing IP (e.g. NAT or VPN).
+        """
+        try:
+            host = urllib.parse.urlparse(self.REST.endpoint).hostname
+            with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
+                s.connect((host, 80))
+                local_ip = s.getsockname()[0]
+        except Exception as e:
+            logger.debug('Routing query to ogcore failed (network not ready?): {}'.format(e))
+            return None
+
+        for iface in nets:
+            if iface.ip == local_ip:
+                logger.debug('Selected interface {} ({}) for ogcore at {}'.format(
+                    iface.name, local_ip, host))
+                return iface
+
+        # Routing succeeded but no interface matched (NAT/VPN): best effort
+        logger.debug('No interface matched routing IP {}, falling back to {}'.format(
+            local_ip, nets[0].ip))
+        return nets[0]
+
     def _setup_network(self, ca_file, crt_file, key_file):
         """
         Background thread: waits indefinitely for a network interface, then
@@ -159,8 +190,8 @@ class OpenGnSysWorker(ServerWorker):
             try:
                 nets = list(operations.getNetworkInfo())
                 if nets:
-                    self.interface = nets[0]
-                    if t > 0:
+                    self.interface = self._best_interface(nets)
+                    if self.interface and t > 0:
                         logger.debug("Network interface found after {} seconds".format(t))
                 else:
                     logger.error('No network interfaces found')