subnet bridge

[oakz]

Hi, had a strange (or not) thing happen recently on my home LAN.
wanted to get feedback.

background:

ISP modem (cable internet) providing DHCP on subnet 192.168.0.1.
Fed into 2 APs via ethernet ( with static IPs in each) 192.168.0.100 & 192.168.0.200.
DHCP pool was 192.168.0.150-192.168.0.199.

Each of these APs where actually routers setup as APs as per the guide on the SNB site. one was an asus rtn56u, other was a tplink archer.(running ddwrt)

anyway, i got a new ISP. It's modem was creating a network on 192.168.2.1, with the dhcp pool from 192.168.2.100 - 192.168.2.200.

First thing i notice, which is normal, is that the wireless clients on the AP 192.168.0.100 (the TP link archer) can't get to the internet. I changed the tplink static IP to 192.168.2.50 however, and all was well.

Then i am thinking, i need to do the same on the rtn56u (that is, make it's static IP 192.168.2.60, from it's current 192.168.0.200). But to my surprise, clients connected to that AP can still get to the internet.

why is that the case? how would 192.168.2.1 be visible from 192.168.0.200 and then how would all the wireless clients on 192.168.0.200 be getting DHCP addresses from 192.168.2.1? you'd think the networks would not be visible both ways. subnet mask was 255.255.255.0

and furthermore, why would the tplink archer be behaving one way and the 56u another, since both were just APs on the same network.

 

[coxhaus]

The clients should work whether the IP on the AP is set correct or not. The AP should just allow DHCP to flow to the wireless clients. The IP for the AP should just be a management IP address used to access the device for changes. I think you are seeing differences in programing of the units. One thing to remember is DHCP is a broadcast from a client without an IP address looking for an IP address from a DHCP server.