Network configuration with a Comcast SMS gateway

pjnutt used Ask the Experts™
I have a new client with a hacked together network.  They run a SMS gateway and a dlink wireless router.  They also need a small (4 port) switch to handle all the network connections.  I am having a horrible time trying to work with the SMS gateway and the DLINK router.  I figured I could just run a cable from the SMS to the DLINK and plug my switch into the DLINK router.  Anytime I would plug the switch into the router, it would take the router connection offline to the SMS gateway.  This client also have 3 different vonage phone phones I need to wire in.  I know the fact that the gateway and router are both trying to handle DHCP is tripping me up, however; I'm not sure how this thing needs to be wired and what I need to do to the DLINK wireless router to make it work with the SMS gateway AND my small unmanaged switch.  Can anyone provide me some insight?

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Top Expert 2010

Do you have the make and model of the Dlink and switch?
Either you are creating a layer 2 loop or the port you are plugging the switch is a shared port that
the Comcast SMC Gateway is using (uplink port might be share with one of the switch ports; you can only use one or the other). Maybe a network diagram of of what you are connecting
and what ports you are using might help.

Your network should go like this

Comcast SMS LAN 1
into WAN on DLINK

DLINK LAN 1 into Switch

>Log into Comcast unit, IP should be
Disable firewall and disable DHCP
There is an option that says Disable firewall for true static IP subnet or something
Disable the smart packet option too if its checked
Now log into the DLINK and set the WAN as follows

Static IP

This is assuming the Comcast unit is, if the customer needs to keep the subnet for the phone you can change the DLINK to hand out with its own IP on the LAN side of BUT FIRST you will need to change the Comcast SMS LAN to be something else like and then change the DLINK WAN settings to match.

Got it?


I will give it a try in the morning and report back.  Thanks for the input.
Another way of doing it:
Leave the gateway as is. Disable DHCP server on D-Link router. Connect ethernet cable from a LAN port on the gateway to a LAN port on D-Link router. Connect the switch to any LAN port on D-Link.



Your solution worked great.  I just have one question, where did you get the IP's for the DNS settings?



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