Linux firewall policies not working as expected when connecting two VPNs

Question

I have to VPNs joint together with an route:

ip route add 10.6.0.0/24 via 10.6.1.2

All Servers on both networks are able to ping each other. However I cannot connect to a service from the client 10.6.1.3 to 10.6.0.1 port 6443. The firewall on the VPN server 10.6.1.1 tells me:

[UFW BLOCK] IN=wg0 OUT=wg0 MAC= SRC=10.6.1.3 DST=10.6.0.1 LEN=64 TOS=0x00 PREC=0x00 TTL=63 ID=0 DF PROTO=TCP SPT=64637 DPT=6443 WINDOW=65535 RES=0x00 SYN URGP=0

the ufw rules look like this:

To                         Action      From
--                         ------      ----
22/tcp (OpenSSH)           ALLOW IN    Anywhere
51820/udp                  ALLOW IN    Anywhere
443/tcp                    ALLOW IN    Anywhere
Anywhere on wg0            ALLOW IN    Anywhere
6443                       ALLOW IN    10.6.0.0/16
10.6.0.1 6443              ALLOW IN    10.6.1.3
22/tcp (OpenSSH (v6))      ALLOW IN    Anywhere (v6)
51820/udp (v6)             ALLOW IN    Anywhere (v6)
443/tcp (v6)               ALLOW IN    Anywhere (v6)
Anywhere (v6) on wg0       ALLOW IN    Anywhere (v6)

Anywhere                   ALLOW OUT   Anywhere on wg0
10.6.0.0/24 6443           ALLOW OUT   10.6.1.0/24
Anywhere (v6)              ALLOW OUT   Anywhere (v6) on wg0

I am unable to find out what is missing, so that I can connect to the port 6443.

Answer 1

I figured that I had to setup ufw routing options as well.

ufw route allow in on wg0 out on wg0
ufw route allow out on wg0 in on wg0

that did the trick for me.