I recently (today) got the VDSL modem from EDPnet. Basically it looks like it’s the exact same modem and firmware used by Belgacom, which is crap, but I won’t go into that now 
Check this great blog post by Patrick Vande Walle and his bbox tricks page for some good tips and tricks.
So, the first thing I wanted to do is change the default 192.168.1.0/24 subnet into my own subnet. My main reason for this is that I don’t want to renumber my current network. I have about twelve hosts on my LAN any given day. Additionally I wanted to setup mac address based static IP’s as well, which Patrick explained nicely.
To change the LAN IP-address I first had to fix some weird configuration bug that came with my Sagem. By default it was setup to bridge the LAN with a bunch of WANs, which were btw none of the WANs you would normally want to bridge with anyway. The problem with this config is that every time you try to save any change to the LAN bridge it would complain that “Only one WAN connection can be enslaved by each bridge”. Anyway, this bridging to these unused WANs doesn’t make sense, so I just removed them by unchecking them:
Go to Advanced Settings > Network Interfaces > LAN Bridge > Settings
Then uncheck all the WAN interfaces. They are named WAN ETHoA 3 etc. Now you can also change the IP-address of the “Network: LAN”. Basically this is the IP-address of the Sagem itself on the LAN network. Also set the DHCP server to reflect your new subnet. Otherwise you will have to statically configure an IP-address on your computer in the same subnet of the Sagem. Set the first DNS server to the same IP-address you gave the LAN network. This is the DNS-server that is distributed through the DHCP response and is nothing more then a relay for the DNS-servers that automatically get configured on your WAN connection. Click “Apply” at the bottom on the page to save your settings.
The final configuration should look something like this:
Click “Apply” at the bottom on the page to save your settings.
Check Patricks blog post for setting Mac address based static IP-addresses.