[SOLVED] Cisco/Linksys E3500 invisible behind ATT BGW210-700?

[sddjd]

This year we had fiber installed by ATT, including their BGW210-700 as the main router/hub for our ethernet cabling (fiber > BGW > Switch > house cat6).

I have a Cisco E3500 connected, this serving as our wifi interface for our home devices (our policies, IP's, etc, were carried over). The radios on the BGW are disabled, and the Cisco router is working correctly in what I understand is cascaded mode (but not fully, see below).

HOWEVER, while I can "see" the E3500 connected to the BGW in its status page as well as the ATT Smart Home app, I cannot access the E3500's management page.

The ATT router shows the E3500 connected via ethernet with a LAN IP assignment in a completely different IP range than that set up on the ATT router (for example, the range specified for all our devices may be 123.456.78.100-199). The E3500 reports its LAN IP through the Linksys app as 12.34.56.250. I have no idea where this IP address originated, and the ATT router status page assigns it to the IP I allocated.

The ATT router has cascaded mode disabled based on input from their tech support (I suspect this setting, but am not certain how to configure this with the Linksys/Cisco).

I may be making this more confusing, but I don't even know where to start with how to access the E3500's management page. I'm shopping for a newer high-speed wifi router currently, but don't want to invest in a new piece of hardware and run into the same problem. ATT's forums are of no help. Thanks for any input!

 

[SamirD]

Att's gateways are funky to say the least.

They have a DMZ mode which actually will give the public IP to the cascaded router.

However, that means that you can't access it from the lan because it's not on the ATT lan.

The best thing you can do is not use the e3500 as a router, just as an access point--disable the dhcp server on it, and give it an address in the att subnet and connect it lan to lan to the att. Then you should be able to hit the management page by doing to the address you assigned and everything should work as intended.

 

[sddjd]

Thank you Samir (as always). That makes more sense even to my limited understanding