Hello everyone!
I have a subnet 192.168.8.0/24 and the OpenWRT used 192.168.8.1. Also, I used 192.168.8.228 as Tailscale subnet router with tailscale up --advertise-routes=<CIDR> --snat-subnet-routes=false --accept-routes, then connected to another subnet 192.168.5.0/24 (subnet router is 192.168.5.228). Check Site-to-site networking · Tailscale Docs
I also configured some zone forwarding on OpenWRT and static routes forwarding, also configured NAT rules but I hope to disable it later. But I didn't enable IP masquerading because I hope to get the origin real IP address.
Now, 192.168.5.2 can access all servers in 192.168.8.0/24 (include Web services), and 192.168.8.0/24 can ping 192.168.5.0/24 properly. But the question is, I use 192.168.8.2 to connect a web server 192.168.5.168, the connection will be reset. I tracked every router traffic by tcpdump, I found the traffic on 192.168.5.228 and 192.168.8.228 are normal, the TCP SYN arrived 192.168.5.168 and replied SYN-ACK via subnet router, but 192.168.8.2 didn't receive it.
How should I do? Any ideas about how to debug on OpenWRT or track the traffic?
Internet
|
------------------------------------------------
| |
192.168.5.1 192.168.8.1
（Gateway） （OpenWRT）
| |
--------------- ---------------
| | | |
192.168.5.228 192.168.5.168 192.168.8.228 192.168.8.2
（Tailscale （Web Server） （Tailscale （PC）
subnet router） subnet router）