Changing DNS in network-admin

[Loïc Martin]

Hello,

I connect to the internet through a Netgear router. The problem is,
network admin wrongly detects its address as a DNS, and even when I
change the DNS, putting the ones my router tells me (they work) sooner
than later it reverts back to the router address (thus no browsing, even
no sending emails...). Tonight, it seems as if I don't even have time to
load a page before the problem appears.

Does anyone know how to force the internet setting so the DNS don't get
changed against my will (couldn't at least network-admin ask my
agreement before doing something like that)?

Thanks,
Loïc