Interconnecting Netgear DSL Router to Cisco 3550 Router for Internet Access

CChambleeJr1961CChambleeJr1961 Registered Users Posts: 1 ■□□□□□□□□□
I've about pulled what little hair I have out of my head on this one, and need some configuration help.

I have a Cisco Catalyst 3550 switch with five Windows 7 desktops, an Avaya PBX and five Avaya IP phones attached. All of these devices are on a subnet, and are communicating properly. I will refer to this as network # 1. I also have SEPARATE network, we'll call network # 2, using AT&T ADSL service and a Netgear 4-port/wireless router/ADSL modem combo device, which is functioning properly with a couple of other Windows 7 desktops over its own wired Ethernet network, using DHCP, and also on a subnet. I thought it would be a simple integration, just plugging one of the 3550's ports to one of the DSL router's ports, in order to give the five Windows 7 desktop computers on network # 1 internet access via the DSL modem. Guess I was wrong. When I connect the two switches together, although I get a good connectivity (green lights on both ports) and am able to ping the DSL router's gateway address ( from network # 1's computers, the computers on network # 1 cannot access the internet. Also, the working computers on network # 2 lose their internet access as long as the two switches are connected together. I am not a Cisco guru, but there's got to be a way to make this scenario work. Can someone provide me with a 3550 configuration that will allow me to extend my internet service from network # 2 on the DSL router to my 3550 switch and their computers? Here's what I am looking for:



  • HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    You will need to log into the Cisco 3550 with a serial cable and post the running config. It could be as simple as using a cross over cable to changing the config on the switch. Posting the running config will help a lot and what port is the trunk port connecting the 3550 to your modem. Sounds like its a flat network but the switch port connecting to the modem might not be setup correctly.
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
  • santaownssantaowns Member Posts: 366
    On the Cisco device what is the default gateway setting? Like the above if you post your config I will help you
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