I am absoluteley stuck and would really apreaciate your helping hand.
Situation:
one ISP Router (FritzBox)
one OpenWRT Router (AP01)
For the configuration, please find the attached pictures.
Problem:
If my PC is connected to the OpenWRT WLAN, I cannot reach the ISP Router
PC:192.168.0.100
ping to 192.168.0.1 OK
ping to 192.168.1.1 OK
ping to 192.168.1.254 NOT OK
If my PC is connected to the ISP Router, I cannot reach the OpenWRT
PC:192.168.1.100
ping to 192.168.1.254 OK
ping to 192.168.1.1 NOT OK
ping to 192.168.0.1 NOT OK
Even if I connect to the OpenWRT AP by SSH and do a ping -I eth0 192.168.1.254, the router cannot reach the ISP Router.
And I do not know why the default gateway is not correct.
You need firewall rules to forward between the two networks.
This is all done for you in a default configuration. I suggest starting there rather than trying to rebuild the whole thing from scratch. The wifi side would be lan and the Fritzbox side would be wan. This is called a routed AP.
If you don't need (or want) to isolate wireless users from the wired network, the most common setup is a bridged or "dumb" AP. This has only one network so there is no need for a firewall configuration.
Now it is configured correctly, assuming that you have a route to 192.168.0.0/24 via 192.168.1.1 either on 192.168.1.254, or on every host in the 192.168.1.0/24 network.
If you can't add that route, plain routing is impossible, and you should revert to default firewall setup with masquerading.
This route is already in place, but I do not think that this is the problem.
The below output shows my PCs configuration while I am not connected to the AP but to the ISP Router
C:\Users\some.user>ipconfig
Windows IP Configuration
Wireless LAN adapter Local Area Connection* 2:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Wireless LAN adapter Wi-Fi:
Connection-specific DNS Suffix . : fritz.box
IPv4 Address. . . . . . . . . . . : 192.168.1.123
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.254
Ethernet adapter Bluetooth Network Connection:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Tunnel adapter Local Area Connection* 13:
Connection-specific DNS Suffix . :
IPv6 Address. . . . . . . . . . . : 2001:0:9d38:6ab8:9:15d4:3f57:fe84
Link-local IPv6 Address . . . . . : fe80::9:15d4:3f57:fe84%8
Default Gateway . . . . . . . . . : ::
C:\Users\some.user>ping 192.168.1.1 -n 2
Pinging 192.168.1.1 with 32 bytes of data:
Reply from 192.168.1.123: Destination host unreachable.
Reply from 192.168.1.123: Destination host unreachable.
Ping statistics for 192.168.1.1:
Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
C:\Users\some.user>ping 192.168.1.254 -n 2
Pinging 192.168.1.254 with 32 bytes of data:
Reply from 192.168.1.254: bytes=32 time=1ms TTL=64
Reply from 192.168.1.254: bytes=32 time=1ms TTL=64
Ping statistics for 192.168.1.254:
Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 1ms, Maximum = 1ms, Average = 1ms
C:\Users\some.user>
Do a traceroute to the Openwrt when you are connected to the ISP router: tracert 192.168.0.1
Is there some setting in the ISP router to isolate LAN from Wifi or to isolate all clients?
There is no setting to isolate, I think it is very strange that the LAN port (eht0) does not respond to ICPM echo requests if I am connected to the same Network.
If I am on the WLAN of the OpenWRT device I am able to ping the 192.168.1.1. but my src net is 192.168.0.0/24 in that case.
C:\Users\some.user>tracert 192.168.0.1
Tracing route to 192.168.0.1 over a maximum of 30 hops
1 1 ms 1 ms * fritz.box [192.168.1.254]
2 fritz.box [192.168.1.254] reports: Destination host unreachable.
Trace complete.
Most likely the routing table on 192.168.1.254 is incorrect, or it doesn't permit LAN-LAN forwarding.
Either fix it, or create a static route on your Windows host.
The routing table on 192.168.1.254 is correct, to demonstrate it I have set the default gateway of my pc to the local interface of the OpenWRT router ... see output below
Sorry to mention this over and over but to me it seems that the eth0 is the issue somehow, e.g. not connected to the switch ports.
C:\Users\some.user>ipconfig
Windows IP Configuration
Wireless LAN adapter Local Area Connection* 2:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Wireless LAN adapter Wi-Fi:
Connection-specific DNS Suffix . :
IPv4 Address. . . . . . . . . . . : 192.168.1.123
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
Ethernet adapter Bluetooth Network Connection:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Tunnel adapter Local Area Connection* 13:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
C:\Users\some.user>tracert 192.168.0.1
Tracing route to 192.168.0.1 over a maximum of 30 hops
1 PC [192.168.1.123] reports: Destination host unreachable.
Trace complete.
C:\Users\some.user>ping 192.168.1.1
Pinging 192.168.1.1 with 32 bytes of data:
Reply from 192.168.1.123: Destination host unreachable.
Reply from 192.168.1.123: Destination host unreachable.
Ping statistics for 192.168.1.1:
Packets: Sent = 2, Received = 2, Lost = 0 (0% loss),
Control-C
^C
C:\Users\some.user>
