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Portland, ME

1 edit

New 6100 modem and connect to network trouble

I have received the 6100 modem and my dsl is active.
I have three computers.
a: server
b: workstation
c: workstation
They are currently each attached via ethernet cable to a 5 port netgear gigabit switch. their ip and gateway are set (eg.,, etc.)
They all communicate with each other, etc.
I tried to set up the DSL modem and plug it into the switch also but it does not work.

How do I set up the dsl modem to work with my system so that I do not interrupt the current network. I need the workstations to communicate with each other, etc?

Thank you.

Milford, NH
·G4 Communications
·Fairpoint Commun..
·Hollis Hosting
Welcome to BBR,

PCs and modem need to be on the same subnet to talk to one another. 100.100.100.x is a poor choice for a local network as it is a public IP address range used by hosts on the Internet.

For typical home network where the ISP provides a single IPv4 address Network Address Translation (NAT) is used to allow an unlimited number of devices to share the connection. RFC 1918 defines three blocks of private address that can be used and reused as they are not used on the Interest. The most common address range for home networks is 192.168.x.x. Devices on the LAN are assigned a private address. Devices use that address to communicate among themselves for file and printer sharing. When device needs to access another host on the Internet the router translates the device's private IP address to the one provided by the ISP.

Normally for a home network you would set your PCs to DHCP and let the router's DHCP service assign addresses. That way the PCs will be able to access the Internet via the router. Since all the devices are on the same subnet file and print sharing will work normally.

If you want to make sure the specific IP address issued by the DHCP server does not change, most routers have a way to bind the the IP address to MAC address. That way a given device will always be assigned the same IP address as long as its hard coded MAC address does not change.

If you don't want to allow the router to dynamically assign IP addresses you can assign them statically. However if you do so you need to make sure they are within the same subnet used by the router and need to assign: IP address, subnet mask, default gateway and DNS server address to each device on your LAN.