Comcast High-Speed Internet through a router?

[Enforcer]

I've tried in vain to get my Linksys router (WRT54g v.2.2 with latest firmware) to work with our new Comcast cable modem. This has included Linksys' own instructions to clone my iBook's ethernet card's MAC address to the router and then powercycling everything. Any ideas? My last resort is to actually call Comcast, and I'd really like to avoid that because they suck at everything they do (but are the only game in town for my building).

Also, if someone knows how to setup an Airport Express with Comcast, that'd be fine too as I have both. All hardware and software information is included below:

Laptop: 1.2ghz G4 iBook (12" screen) with 1.25GB RAM, 32MB Video RAM, 120GB HD, standard ethernet card and Airport card; running latest update of Tiger

Linksys Router: WRT54g v.2.2 with latest firmware. Default factory settings. This router has 4 wired LAN ports in addition to wireless b/g

Airport Express "router": Setup with default factory settings.

ISP: Comcast High-Speed Internet via cable modem. The modem itself is a Motorola and works great when connected directly to my iBook via ethernet cable.

Naturally if I get one of the routers to work, I'll be applying wi-fi security (WPA2) and the like, but the trick is getting there. I appreciate any and all help!

 

[drothgery]

If you haven't tried this yet -- unplug the cable modem for a minute between connecting directly to your PC and connecting to the wireless router. It needs to be reset when it connects to a new device. This drove me nuts the last two times I got a new PC, and when I got my wireless router.

 

[ThirdWizard]

What problem are you having? Can you get on the LAN but not outside?

 

[Pyrex]

Check to make sure the router and the modem aren't trying to use the same IP address. (I had that problem when I got DSL and it took me a while to figure it out...)

 

[DethStryke]

Set up the connection with the plug-in ethernet card first, then set up Wireless after you get it all working (obviously).

I'm sure you got most of this, but I find it is easiest to go simple-stupid through all the points just as a checklist for missed bits. This saves the "whoops, that's unplugged" syndrome.

Set at defaults, the Linksys should have a DHCP server running and auto-connect the network connection. So plug the Cable Modem to the Router with the RJ-45 cable. Then plug the computer to the first open port on the router. The computer should have the network connection set to "Connect Automatically" with no set IP, DNS, etc.

If any of those items were on prior to this, unplug the router and cable modem for at least 30 seconds to reset them. IF you have a digital voice combo cable modem, this model has a battery backup in the bottom and will not reset by pulling the plug! You will either need to pull the battery too or use the integrated reset (which could have mixed results, but seems to work the times I've done it).

Turn on the cable modem first after the wait and let all the lights become solid. Then turn on the router. Wait for that to boot fully, then turn on the computer.

That should clear all of the issues and reset the connection. After that, you can hook up the wireless or more machines through use of the DHCP server on the router itself.

If you're feeling quite saucy, check out the third-party firmware updates available here:
http://en.wikipedia.org/wiki/WRT54G#Third-party_firmware_projects

That linksys router you have can literally be tricked out to function like a low-level commercial type router ($1200 price tag type deals).

 

[ssampier]

In the router, what connection method are you using?

According to this page, Comcast requires you to connect automatically (DHCP).
http://www.selfseo.com/story-11522.php

Second, according to another site I read, they authenticate traffic based on MAC addresses. If your desktop computer works directly into the modem, but the router does not work, try cloning your desktop MAC on your router.

If that doesn't work, try upgrading the firmware on the router - issues are discovered all the time.

 

[Enforcer]

Thanks for everyone's replies, I got it working!!!

Basically I think I didn't give each device enough time to reset, so this time my process was:

1) Unplug the cable modem and hook up my router to the laptop via ethernet.

2) Clone my laptop's MAC address to the router.

3) Shutdown the laptop and unplug the power to both cable modem and router.

4) With everything still unpowered, make the ethernet connections between modem, router, and laptop.

5) Plug in cable modem, wait five full minutes (I really wasn't going to take any chances this time).

6) Plug in router, wait another five full minutes.

7) Power up the laptop and voila! The router works, both via wireless and ethernet.

I really appreciate all the help, it was you folks that did it for me. Thanks!

 

[ssampier]

I am happy to hear it's working for you.

Those years of DSL and dialup support helped me out (not at Comcast, though, so that's why my advice was fairly general).