GPNC — L2 Bridge Verification

🏗️ L2 Bridge Architecture

Rob's Tester Network Topology:

┌─────────────────┐    ┌──────────────────┐    ┌─────────────────┐
│   Gaming PC     │    │   GPNC Tester    │    │   Home Router   │
│  (enp2s0 side) │────│     br-gpnc      │────│  (enp3s0 side)  │
└─────────────────┘    │                  │    └─────────────────┘
                       │  eno1 (mgmt)     │
                       │  192.168.1.102   │
                       └──────────────────┘

Interface	Role	Status	Description
`br-gpnc`	Bridge Master	✓ Active	L2 bridge for inline packet interception
`enp2s0`	Subscriber Port	✓ Bridged	Gaming PC connection (inline traffic)
`enp3s0`	WAN Port	✓ Bridged	Home router connection (uplink)
`eno1`	Management	✓ Independent	SSH/API access (192.168.1.102)

✅ Quick Status Checklist

Bridge Created: ✅ br-gpnc exists
Ports Bridged: ✅ enp2s0 + enp3s0 are members
TPROXY Active: ✅ tproxy_up: true
iptables Rules: ✅ BROUTE + mangle chains active
Public Access: ✅ 209.121.30.11:40055/40056
Subscribers Detected: ✅ 6 devices on network

🔍 Bridge Configuration Verification

1. Bridge Interface Status

ip -d link show br-gpnc

Expected: br-gpnc: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 state UP bridge forward_delay 1500 hello_time 200 max_age 2000 ageing_time 30000 stp_state 0

2. Bridge Member Ports

bridge link show

Expected: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br-gpnc state forwarding priority 32 enp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 master br-gpnc state forwarding priority 32

3. MAC Address Learning (FDB)

bridge fdb show br br-gpnc

Expected: MAC addresses learned on each port showing L2 forwarding activity

4. Interface Statistics

cat /proc/net/dev | grep -E "br-gpnc|enp2s0|enp3s0"

Shows RX/TX packet/byte counts - should be non-zero if traffic flowing

🎯 TPROXY & iptables Verification

5. iptables BROUTE Rules (ebtables)

sudo ebtables -t broute -L

Expected: BROUTE rules directing specific traffic to TPROXY

6. iptables Mangle Rules

sudo iptables -t mangle -L -n

Expected: DIVERT chain with TPROXY rules and packet marking

7. GPNC API Health Check

curl -s http://127.0.0.1:50055/healthz | jq .

{ "catalog_games": 262, "matcher_keys": 607, "ok": true, "problems": [], "tproxy_up": true, "version": "1.7.18-rob-he-20260514" }

📊 Traffic Flow Verification

8. Bridge Traffic Statistics

curl -s http://127.0.0.1:50056/api/status | jq .interception

Expected fields: - br_gpnc_bytes: Traffic through bridge - intercepted_pkts: Packets caught by TPROXY - delivered_pkts: Packets sent to GPNC engine - active_flows: Current game flows

9. Subscriber Detection

curl -s http://127.0.0.1:50056/api/status | jq '.subscribers[] | {ip, mac, vendor}'

Shows devices detected on the bridge network

📈 Live L2 Bridge Monitoring

🔗 Live Interface Status

Interface	Carrier	State	RX Packets	RX Bytes	Bridge Role
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🌉 Live Bridge Traffic

Bridge State

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Total RX Bytes

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Total Packets

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Last Updated

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📋 Live GPNC Logs

Manual mode

Loading GPNC logs...

🎯 Quick Actions

🖥️ Open Full Dashboard

🚨 L2 Bridge Troubleshooting

Common Issues & Fixes

Issue	Symptoms	Fix
Bridge not forwarding	Zero FDB entries, no traffic stats	`sudo systemctl restart networking`
Ports not bridged	Interfaces show no master	`sudo netplan apply`
TPROXY not active	tproxy_up: false in API	`sudo systemctl restart gpnc`
No MAC learning	Empty bridge fdb	Check physical links and generate traffic

Debug Commands

# Check physical link status
ip link show | grep -A1 -E "enp2s0|enp3s0"

# Check bridge VLAN configuration
bridge vlan show

# Test connectivity through bridge
ping -c 3 192.168.1.254

# Check systemd service logs
sudo journalctl -u gpnc -f

Emergency Reset

⚠️ Only use if bridge is completely broken:

# Full bridge reset (CAUTION - will drop connectivity)
sudo systemctl stop gpnc
sudo ip link set br-gpnc down
sudo netplan apply
sudo systemctl start gpnc

🔧 Verification Checklist

[ ] Bridge interface exists and is UP
[ ] Both enp2s0 and enp3s0 are bridge members
[ ] Physical links are UP on both ports
[ ] Bridge FDB has learned MAC addresses
[ ] Traffic statistics show non-zero counts
[ ] TPROXY shows as active in API
[ ] iptables rules are present
[ ] Gaming devices detected in subscribers
[ ] Public endpoints respond correctly
[ ] No error messages in logs

🎮 Testing Gaming Traffic

To verify end-to-end L2 → TPROXY → GPNC flow:

Connect gaming PC to enp2s0 port on Rob's tester
Start a supported game on the gaming PC
Watch the web UI at http://209.121.30.11:40056/
Verify flows appear in Dashboard and Sessions tabs
Check that traffic is being accelerated through WTFast pathfinders

🌉 L2 Bridge Verification Guide

🏗️ L2 Bridge Architecture

✅ Quick Status Checklist

🔍 Bridge Configuration Verification

1. Bridge Interface Status

2. Bridge Member Ports

3. MAC Address Learning (FDB)

4. Interface Statistics

🎯 TPROXY & iptables Verification

5. iptables BROUTE Rules (ebtables)

6. iptables Mangle Rules

7. GPNC API Health Check

📊 Traffic Flow Verification

8. Bridge Traffic Statistics

9. Subscriber Detection

📈 Live L2 Bridge Monitoring

🔗 Live Interface Status

🌉 Live Bridge Traffic

📋 Live GPNC Logs

🎯 Quick Actions

🚨 L2 Bridge Troubleshooting

Common Issues & Fixes

Debug Commands

Emergency Reset

🔧 Verification Checklist

🎮 Testing Gaming Traffic