Help - Connecting my 2600 router to a cable modem

I am trying to make this setup work:

PC --> 3524 Switch --> 2621 Router --> Motorola Cable Modem

Using static routes on the pc and 2621 I can ping everything but not connect to the internet. I have tried connecting my 2621 to my linksys and having the linksys connect to the cable modem instead, but it changes little as far as results. I also tried putting a default route on the 2621 pointing out the ethernet port on the router connected to it.

I'm guessing it's a nat or dhcp related problem, but I can't figure out what exactly it isand after about 3 hours of messing with this my brain is starting to fizzle out. I have tried turning on dhcp on the 2621 and removing the static route from the pc(switching it back to dhcp/auto-acquire) and that has also not worked but it's likely I'm doing something wrong on the 2621.

I realize there are probably holes in the above information so ask away I'll keep this page open, thanks for any help.

Oh, and the point of me doing this is just that I wanted to be able to play with QoS and so I wanted to have my pc's internet traffic funneling through.

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Comments

mikej412

I'd guess it's both... and depending on your configuration/network, maybe some routing & name resolution tossed in for good measure.

Get your 2600 configured for DHCP and a default route out to the cable modem and ping something out on the internet by IP Address. If the 2600 isn't talking to the internet, its a waste of time futzing with anything else.

If you're using private addresses for your local network, then you have to setup NAT. If your connection doesn't work, ping something out on the internet by IP Address from the PC to see if your routing or NAT is configured correctly (check the NAT translations on the router).

Check out the Connect to Comcast thread -- which also has a link to a "connect home lab to internet" thread (with more links there).

ITdude

mikej412 wrote:

If the 2600 isn't talking to the internet, its a waste of time futzing with anything else.

Is that a networking term I missed in my training?

Steve10393

thanks, bbiab

Steve10393

ok, so I got it halfway operational. But I still have some problems.

I can ping outside addresses, but they all time out for one thing. I configured "ip address dhcp" on my outbound 2600 ethernet interface and then set up static nat translation to an internal private ip address i gave my pc and the dhcp ip given by the cable modem.

I can load trillian and talk to people on AIM but I can't do much else. I don't know why.

Pro Inside global Inside local Outside local Outside global
--- x.x.219.248 192.168.10.2 --- ---

^ is this the problem, not having an outside local and outside global?

dtlokee

You need to use overloaded nat to allow more than one inside host to communicate to the Internet at one time. Remove the current NAT rule and replace it with something like this.

ip nat inside source list 1 interface ethernet0/0
!
access-lsit 1 permit any

now you can change the ACL to allow just your inside hosts to use the nat rule.

Steve10393

ok thx, will do.

Steve10393

ok got it working finally, it was my dns server not being set, which i did set by it's ip in both windows and in the router, which got it finally working.

ITdude

Ah yes, name resolution. What would we do without it?