I am trying to route between multiple WG interfaces. 

On my primary server:

wg0.conf:

[Interface]

Address = 192.168.6.4/24

ListenPort = 51820

PrivateKey = 

PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -A FORWARD -o %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -D FORWARD -o %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE

[Peer]

PublicKey = 

AllowedIPs = 192.168.6.1/32, 192.168.1.0/24

Endpoint = xy.com:51820

wg1.conf:

[Interface]

Address = 192.168.9.1/24

ListenPort = 51821

PrivateKey = 

PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -A FORWARD -o %i -j ACCEPT; iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -D FORWARD -o %i -j ACCEPT; iptables -t nat -D POSTROUTING -o eth0 -j MASQUERADE

[Peer]

PublicKey = 

AllowedIPs = 192.168.9.3/32

---

With wg0 I am connecting to an other server (xy.com:51820). On wg1 I am accepting client connections.

On this server I can ping everything, so connection is working well. 

ping 192.168.6.1 - works

ping 192.168.1.xxx - works

ping 192.168.9.3 - works

---

Now I am connecting my client to this server (client 192.168.9.3):

[Interface]

PrivateKey = 

Address = 192.168.9.3/24

DNS = 192.168.9.1

[Peer]

PublicKey = 

AllowedIPs = 192.168.9.1/32, 192.168.1.0/24

Endpoint = primaryserver:51821

I can ping server 192.168.9.1 as expected, but I am unable to ping any of my devices in 192.168.1.0/24. 

Anyone knows what's the problem here?