I have an interesting networking problem to solve.

[Prisoner_Number_Six]

A client has Roadrunner. They have two computers they need online- an HP desktop, and a laptop (can't remember the brand). Neither computer will pick up an IP either directly from the modem or via a router, no matter what I do. I've quadruple-checked all the settings on the computers AND the modem & router.

I bring their two computers to my office and plug them into my network (at the time of this exercise I was also on RR). They both hook up instantly with no problems.

I have a Dell work laptop. I take it and plug it into both their modem and router and it instantly goes online without problems.

What the HELL is going on? I've done every diagnostic I can think of, and I've been on the phone with their "techies" (term used loosely) and still no joy. I can't dope this one out. What am I missing? (All PCs involved, including mine, are XP SP3. All firewalls are off. All tcp/ip settings are properly set up.)

HAAAALLLLPPPP!!!

[EvolveOrConvolve]

1. You've probably tried all of these but JIC

1. Have you checked the DHCP settings? Do they have static IP addresses?
2. Conversely, if they are setup with dynamic IP addresses, what happens if you give them static IP's that match those that would be leased by the DHCP in the router or modem?
3. If DHCP: are they actually grabbing IP addresses, or does each machine just assign its own local IP address?
4. If they are getting a LAN IP address, can you ping one machine from the other?
5. Again, if they are receiving a LAN IP address, what happens if you run a trace route to www.google.com?

You may have tried all of these, but they're tasks that I'd try if I was in the pickle you're in.

Good luck!

[Prisoner_Number_Six]

2. I've tried all that and more.

I've been through the DCHP settings a dozen times. I've gone over the tcp/ip settings, even resetting it all to the defaults. RR assigns dynamic IPs, but when I had my laptop online there I copied all the info and input it manually into each of the other two machines and got no results. My laptop could ping out with no problems. Neither of theirs would.

They simply refuse to acknowledge a connection to her network, while my laptop instantly sees it with no problem.

While I had their computers at my office I did complete repair installs and upgrades on both machines. While seeing my network with no problem they still ignore theirs.

It's a mystery wrapped in an enigma.

[Why Syzygy]

3. Are you using the same

ethernet cable when you connect your computer to their modem as when you connect their computer to their modem?

[Prisoner_Number_Six]

4. I've tried the same cables and fresh from the store cables

I've also used routers from different makers (D-Link and Linksys).

But... now that I think of it there IS one thing I haven't tried- different NIC cards. Since they worked in one location I never thought to try putting a different one in place.

Shouldn't make a difference, but... I'll be seeing them in the morning. I must remember to take both a new PCI NIC card and a USB NIC connector (for the laptop- it doesn't have wireless capability).

[Why Syzygy]

6. Have their computers ever

connected to any other Internet besides the one at your place? Do they have VPN?

[Prisoner_Number_Six]

7. They used to hook up at their home location with no problems.

No VPN in place- just two plain ol' XP boxes without any computer/computer networking configured. Used for browsing, online banking, etc. Basic stuff.

[Why Syzygy]

8. What kind of network did they have before? nt

[Prisoner_Number_Six]

9. To the best of my knowledge they've had RR for a couple years

which is why this doesn't make sense- AFAIK nothing's changed networking-wise. Which would seem to tie into my personal adage that if something changes from one location to another it's hardware- the question to ask is "what's different?". Hardware-wise the only difference is the modems used, and the RR techies have tested their modem more than once. Besides, MY LAPTOP still connects there!

What's different? I do not know. :shrug:

[Why Syzygy]

10. ah. Sounds like

SOMETHING had to change. If they were tooling along just fine and then suddenly cannot connect, they may have done something?

[david13]

5. I shore don't know, but I hope you post the solution once you find it,

as I would like to know.
dc

[CK_John]

11. Long shot, check the connection options in IE both dial and lan settings. n/t

[Dead_Parrot]

12. A very long shot...

have you checked cross-over vs straight cables/port on the modem? Might be your port is adapting and theirs isn't.

:shrug:

If you hook up via the router and set static IPs, can you get the router to ping the modem? Might give a clue where the failure is.

[MyNameGoesHere]

13. If the NIC's are known to work

on other networks and no problems,and you can get DHCP for other systems then I can only think of one thing maybe. MAC address filtering is blocking them. Make sure they are not in the excluded MAC listing. This would affect both DHCP and static.

[Duer 157099]

16. But if it also doesn't work with just the modem (router taken out of the loop)

wouldn't this be moot?

I'm assuming the MAC filtering is done at the router level (?)

[MyNameGoesHere]

17. I don't know about roadrunner "modems" as you call it

but most "modems" have built in filtering, firewall, and a host of other needless crap that usually gets the average user in more trouble than protecting them.

[RoyGBiv]

18. Not generally ...

The individual use modems most commonly in use today do not have firewalls or MAC filtering, e.g. Motorla SB 5120.

You may be talking about what the cable industry refers to as a gateway. It is in fact a modem, but it has broad use capabilities that combine VOIP and Internet access. These do have MAC filtering and sometimes have firewalls, though the rules for the firewall tend to be set by the access provider and are not accessible by the end user except through a hack.

There are also wireless router/modems that companies sell also referred to as gateways by the industry. These will have filtering and firewalls, of course, but a tech working on this would kinda know that he's dealing with a router and a modem all in one.

OnEdit: After reading through the thread, I'm not entirely clear on what kind of modem is in use here. I discovered with a different problem I was trying to help diagnose some time ago that the person was referring to their gateway as a modem, and I was giving instructions that wouldn't have worked the same on a VOIP modem/gateway/whatever. So, that may be an issue.

[MyNameGoesHere]

20. I'll go with network bridge instead of modem

and not so much gateway as that is another beast. Yes it performs mod/demod but the nuts and bolts are the connection it establishes via bridged network to ISP network. And i cannot believe they are still using these antiquated bricks.

[RoyGBiv]

21. Works for me ...

I knew there was a more appropriate term roaming around in my head somewhere, but I got too much sales training indoctrination. "Gateway" is supposed to be a friendlier term, and we were given 50 lashes for failing to use it.

[SKKY]

14. Just a shot in the dark, but are they using the firewall in XP?

Did you give that a quick glance over?

[Duer 157099]

15. As you suggested, the only thing I can think of is to swap the

network cards.

This would drive me nuts, it seems you have covered almost all of the bases! Let us know how it resolves.

[CK_John]

19. Are there any crossover cables envolved? Usually yellow cat-5 instead of blue or gray. n/t

[Why Syzygy]

22. Did you get this resolved? nt