can't talk to the other node in the same tailnet when using tailscale userspace networking mode

if the tailscaled is run as userspace mode, is it expected it can't ping others ip in its tailnet (100.x.x.x)?
```
ping 100.99.97.85

Pinging 100.99.97.85 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 100.99.97.85:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

tailscale ping 100.99.97.85
pong from node (100.99.97.85) via DERP(sin) in 71ms
pong from node (100.99.97.85) via DERP(sin) in 304ms
pong from node (100.99.97.85) via DERP(sin) in 38ms
pong from node (100.99.97.85) via DERP(sin) in 37ms
pong from node (100.99.97.85) via DERP(sin) in 40ms
```

how you communicate with other node if the regular ping won't work for 100.x.x.x addresses in userspace mode? I tried a simple tcp connection and it always timed out

the tcp server is on vpn mode, and the tcp client is on userspace networking mode, both client and server is on the same tailnet and no firewall installed on the server.

the server can ping the client normally, but not the other way around