Here’s a summarized version of your question that you can share with your friends:
---
Question Summary:
I have a network with multiple Linux PCs and an OpenWRT router configured with three subnets: 192.168.99.0/24, 192.168.2.0/24, and 192.168.8.0/24. One of the PCs (PC B) has two static IP interfaces in the 192.168.99.0/24 and 192.168.2.0/24 networks. While hosts from the 192.168.8.0/24 network can ping PC B at 192.168.99.100, hosts from the 192.168.2.0/24 network cannot. After removing the static IP on the 192.168.2.0/24 interface, the ping works, leading me to believe the issue is due to asymmetric routing.
When I ping from PC A to PC B, it hangs instead of failing immediately. I want to understand how to troubleshoot asymmetric routing in the future and whether setting up masquerading on the router would solve the issue.
---
Feel free to modify it if you need to add or change any details!