VPN Routing Chaos — When Traffic Gets Lost in Translation!

🌐 VPN Routing Chaos — When Traffic Gets Lost in Translation!

🛰️ The Situation

Imagine you're managing all your branches smoothly — everything is working perfectly — until suddenly, everything goes down! The VPN drops, systems can’t communicate, and when you start running ping tests, you notice that edge devices can still see each other… but you, as the Admin, can’t access any other branch 😅 You decide to run a trace just to see what’s going on — and the traffic reaches the edge router… then completely disappears!

🧩 The Diagnosis

Strangely enough, you can still access the firewall from only one IP — the rest are completely dead. No configuration changes, no one touched the servers — everything *should* be fine. You contact the NOC Team and they confidently say:
“Everything looks fine from our side; the routers are communicating normally!”
And that’s when the journey to prove the opposite begins 😂
You open the SIEM platform, start reviewing the flows, and run ping tests between two branches using different IPs. Then comes the surprise: the traffic isn’t even reaching the firewall!

🔍 The Root Cause

At that point, you knew it had to be a routing issue. You requested the routing table from the NOC and started reviewing it line by line… and there it was:

192.168.0.0/16 Static 60 0 RD 192.168.0.1 Vlanif1

Instead of correctly routing the traffic to the firewall:

192.168.0.0/16 Static 60 0 RD 192.168.0.150 Vlanif1

That meant the traffic was looping back to the router itself instead of passing through the firewall — causing it to vanish before reaching the control point.

🛠️ The Fix

I calmly explained the network topology and how the firewall acted as the main gateway controlling all traffic. After a long call and several traceroute and ELK SIEM tests, we confirmed the issue. Once the NOC team corrected the static route to point to the firewall IP instead of the router, everything came back online 💪

💡 Lessons Learned

- In complex network issues, the obvious culprit isn’t always the real one.
- Always review the routing and verify paths using traceroute.
- If you have a SIEM or monitoring tool, trust it — data doesn’t lie.
- Stay calm and analyze logically — not emotionally.

🔧 Tools Used

- traceroute
- ELK SIEM
- Patience 😅

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#Network #VPN #Routing #Firewall #ELK #SIEM #Cybersecurity #Troubleshooting