Connect a Cisco router 2611 to ADSL2 modem

danyaleixo · Post by **danyaleixo** » Tue Jan 29, 2008 8:40 pm

Hi, I would like to connect a Cisco router 2611 to my current 02 - ADSL2+ modem, so I could have access to the internet. My current ISP is O2 Broadband.
I am not really sure if I should use a cross-over cable or a straight- through cable for this connection. Also, I would like to know if I have to configure both router and modem, so they could communicate to each other. I heard I would have to use some kind of encapsulation; is that true?

When I connect my router to the ADSL2 modem using the Ethernet port on both router and modem, either by cross-over or straight- through cable, the green led stays on, and I also can ping both router and modem successfully, but still can no have access to the internet; wonder why?

Just want to add here that I don’t have any problem to connect to the Internet using my ADSL2 modem. I would like to use my Cisco router as well for my home network; and that’s where all the trouble starts.

Please help me! I really need to do this connection

Thanx

Danilson

ErikD · Post by **ErikD** » Fri Feb 01, 2008 7:40 pm

What do you know about configuring Cisco devices? This is an enterprise class router, it is NOT just plug and play. You need to configure it from the ground up, out of the box it will have no configuration at all.

If you connect a PC directly to the modem do you get a DHCP assigned IP? If so is it public or private? Do you want to setup the Cisco router in a NAT configuration?

danyaleixo · Post by **danyaleixo** » Wed Feb 06, 2008 10:21 am

I never said it was a non enterprise class router, or a plug and play router. That was never my question!

I already have my internal network with Cisco devices (2 x routers, and 1x 2950 Switch) up and running without any problem. And of course to do this I needed to have a basic knowledge to how to configure Cisco devices. My router assigns IP addresses dynamically to all computers connected to the Switch using class C address of 192.168.1.0 /27.

My computers are not connected to the modem, but to the switch! Yes as you noticed with the IP address that I am using it’s a private ip address.

What I really want is to connect my internal network to the outside world. And for this I have a ADSL+2 modem from O2 Broadband Service Provider, with a Public and STATIC IP address of 78.86.168.33/20.

And I am not really sure how to make these two devices communicate with one to another. I hear that I should configure my router using PPPoE (Point-Point Protocol over Ethernet) encapsulation. And that all i know at this stage!

And the other question about if I wanted to setup the Cisco router in a NAT configuration; to be honest with you, I don’t know. Would I have to do that to have these two devices to exchange information? If that’s the only way, of course I will try doing that! Do I have to setup the Cisco router in a NAT configuration?

Thanx

Danilson

ErikD · Post by **ErikD** » Thu Feb 07, 2008 7:30 pm

What is your whole network setup? Why two other routers?

The more you let us know what is going on, and what you want to get done the easier it will be. Draw out a simple network diagram showing what connects to what. As far as needing PPPoE that would depend entirely on your ISP, some require it some don't, so check with them.

Post by **YeOldeStonecat** » Fri Feb 08, 2008 7:36 am

Please explain your current setup....you say you're using 2x routers already?

First thing you need to know...is what your ISP requires for a configuration on your WAN interface. PPPoE ...you usually leave your WAN setup as "Obtain Auto"...or "Dynamic IP"...even if you have a static IP account. I've not seen an ISP that has you manually enter your static IP on the WAN interface with a PPPoE system.