Fix gluetun MTU for k3s Flannel network

eth0 MTU in pods is 1450 (Flannel VXLAN). gluetun's MTU discovery was setting tun0 to 1440, making WireGuard outer packets ~1500 bytes which exceeds the 1450 limit. TLS ClientHello gets dropped, causing startup check to fail and loop. Fix: set MTU=1320 so WireGuard UDP packets stay well under 1450.
2026-04-15 02:32:51 -05:00
parent de94ca216a
commit 8d6dd27435
1 changed files with 4 additions and 0 deletions
@@ -112,6 +112,8 @@ spec:
              value: "10.43.0.10:53"
            - name: FIREWALL_OUTBOUND_SUBNETS
              value: "10.42.0.0/16,10.43.0.0/16"
+            - name: MTU
+              value: "1320"
          volumeMounts:
            - name: gluetun-data
              mountPath: /tmp/gluetun
@@ -360,6 +362,8 @@ spec:
              value: "10.43.0.10:53"
            - name: FIREWALL_OUTBOUND_SUBNETS
              value: "10.42.0.0/16,10.43.0.0/16"
+            - name: MTU
+              value: "1320"
          volumeMounts:
            - name: gluetun-data
              mountPath: /tmp/gluetun