pin NIC names to MAC + limit 7DTD restart loops

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

services/game-servers.nix

@@ -171,6 +171,23 @@
       };
     };
 
+    # Stop 7DTD containers from crash-looping forever — after 5 failures
+    # within 5 minutes, systemd gives up.  Without this, a broken container
+    # spawns a new veth pair every 30 s, flooding systemd-networkd and
+    # potentially interfering with DHCP on the WAN interface.
+    systemd.services."docker-7dtd".serviceConfig = {
+      Restart = lib.mkForce "on-failure";
+      RestartSec = "30s";
+      StartLimitIntervalSec = 300;
+      StartLimitBurst = 5;
+    };
+    systemd.services."docker-7dtd-coop".serviceConfig = {
+      Restart = lib.mkForce "on-failure";
+      RestartSec = "30s";
+      StartLimitIntervalSec = 300;
+      StartLimitBurst = 5;
+    };
+
     networking.firewall.allowedTCPPorts = [ 26900 26910 ];
     networking.firewall.allowedUDPPorts = [ 26900 26901 26902 26910 26911 26912 ];
   };

services/router.nix

@@ -75,6 +75,21 @@ in
     # --- Interface configuration ---
     systemd.network = {
       enable = true;
+
+      # Pin interface names to MAC addresses so they never swap across boots.
+      # Without this, "eth0" is an unpredictable kernel name that depends on
+      # device probe order — if the NICs swap, the entire LAN/WAN config breaks.
+      links = {
+        "10-wan" = {
+          matchConfig.MACAddress = "6c:0b:84:0c:4c:59";
+          linkConfig.Name = "eno1";
+        };
+        "20-lan" = {
+          matchConfig.MACAddress = "6c:0b:84:0c:4c:58";
+          linkConfig.Name = "eth0";
+        };
+      };
+
       networks = {
         "10-wan" = {
           matchConfig.Name = "eno1";