I am in something of a bind my normal internet access i no longer with us as the 2G mobile network has been tuned off and although I have many years experience on Linux, little of this has been with the network config as (almost) always works "out of the box". The current situation is a have a Dlink 4G modem router, this has an IP address of 192.168.0.1. This is to be connected to my fire wall machine (currently running Debian 7) via a cat 5 cable to eth0. This machine has a 2 ethernet port motherboard, the second port eth1 will be connected to a (I think) switch which has my other 4 machines connect to it. The IP address range is currently 92.168.1.1 (gateway) upwards with 6 address's in use. How is the firewall ports configured, is there a decent explantion on the net (remember I know little about the low level nuts and bolts but would like to find out. I assume the 2 ports on the firewall machine will use 2 different IP address, is there any logic in there allocation, I also assume the default route for this machine will be eth0 (the port connected to the 4G modem router. In Debian in the /etc/network/interfaces file how is the default route determined. Help, will be GREATLY appeciated. Trying to get new internet access for when the 2G network was gone has been a real struggle. At this location only 2 options are availible, NBN satelite and 4G mobile broadband, unfortunately there is little information anywhere on how to configure either of them for linux. I tried satelite NBN but could not get ANY kind of reliable connection. A 4G dongle will work on linux but I could find NO config information at all and it appears plenty have tried and failed. THe current solution has been adopted as it only means setting up ethernet ports and doing bit of routing. Lindsay