[tlug] Problems with au ADSL/network setup

["Stephen J. Turnbull" <stephen@example.com>]

Stefan A. writes:

 > The problem: My friend uses some older type of au ADSL with a modem
 > which he rented from his provider. The modem only has one Ethernet LAN
 > port and no wifi (au charges extra for wifi), so he connected an IOData
 > WN-G54/R4 router to the modem a few years ago to share his connection
 > between several local systems (by cable) and his smartphone/tablet
 > (wifi). This worked well until a few months ago, when he couldn't reach
 > his router's admin interface anymore. Suspecting that the router was at
 > fault, which was by now pretty old and didn't support WPA2 anyway, I
 > gave him a spare Buffalo WHR-G301N router. But after hooking it up to
 > his modem, I was baffled to find that the same thing happened. The
 > modem seems to overwrite the IP addresses allocated by the router(s)
 > shortly after connecting them, making it impossible to reach the
 > router's admin interface. Wifi is still working, but my friend reports
 > that it breaks down occasionally, making a reboot of the (Buffalo)
 > router necessary.

It sounds to me like the router is functioning as a bridge (less
likely) or as Darren suggests the two routers (the ADSL modem and the
Buffalo router) are competing to manage the same subnet with DHCP.  I
would guess the intermittent breakdown occurs when a lease expires.

 > recommend throwing out all that old garbage, upgrading to Hikari (since
 > his connection is quite slow) and getting a new router from au,

If he's happy with his current setup, that shouldn't be necessary,
although the difference in performance would be enormous.

I would check to see if the two routers are serving the same IP
subnet, and if so, make a separate subnet for the Buffalo router's
clients.