12.1.2T ip address dhcp

[kojack96]

I see there is a similar post here regarding this question but I though I would try to get an answer.
I am trying to connect a cisco 2611 to a cable modem.
I used IOS 12.1.2T and configured Eth 0/0 to ip address dhcp
I had my PC conected and noted the DHCP server it was connecting to. The MAC address of my PC and the DNS servers.

I then unpluged my PC from the cable modem and pluged in my router I saw the router try to find the DHCP server but eventualy after several tries it times out and stops tring.

My question is can I get the router to try and renew its address again without restarting the router and any suggestions as to why I cannot obtain an address or find the DHCP server?

Regards

 

[svermill]

You can probably shut and no shut the interface to get the re-tries going. I don't have any experience with this relatively new feature, but I do know that a lot of cable ISPs restrict you to one single MAC. They probably have your PC mac address locked in. You may need to call them.

 

[rburke]

Actually the cool thing with cisco's is the ability to clone mac addresses. All you have to do is find the mac address of the PC that was originally connected and registered, and then use the "mac-address xxxx" command on the interface that is connecting to the cable modem. That should fix the problem for hte mac-address registration.

burke

 

[svermill]

Well, I resisted that recomendation because I assumed that that same PC would be attaching to the router. Duplicate MACs would be a no-no.

 

[rburke]

Well, it is worth a try, if worse comes to worse then he could go buy a $10 NIC and keep the old one just in case he ever needs it. Just an idea... kojack96, who is your ISP?

burke

 

[svermill]

burke,

You are absolutely correct. As a troubleshooting technique, this is a good approach. At least then he would know exactly what the issue is. I suspect he would find his router able to get an address using that MAC.

Incidentally, did you get your FR up and running the way you want it?

kojac96,

If the PC has already been attached to the router, remember to clear your ARP cache or you are likely to have new problems (it may not even take).

 

[rburke]

svermill,
No not really, I tried using hte frame map commands, ut it never worked. EVERYTHING looked good, and the wierd thing is that if I swapped the routers and the IOS 11.2 was the DCE and the 12.0.6 was the DTE it would work. It was only for a home lab, but since not many people were responding to it I just scrapped it and went back to the other way it worked. But if you have any other ideas then I'll try it again....

burke

 

[svermill]

Well, I don't have any images laying around that are quite that old and my lab is all 1700s and 4000s at the moment so I can't duplicate your issue. It seems odd that it would be an IOS issue but you never know. There are really two ways to do back-to-back frame relay. The first is in that link I gave you. It doesn't make use of LMI. It is a really basic way to go about it and it isn't very good frame relay practice. If you followed the other example that was hyperlinked in the link that I posted, I'm stumped. I've used that kind of setup many times. But it doesn't sound like your loosing much sleep over it. Just one of them things....

Sorry for the off topic.

 

[rburke]

One more off topic remark...

Yeah, the reason I'm not too worried aout it is because I picked up a 4500M and I'll make a real frame-relay switch, then if I feel like it I'll mess around with the back-to-back again. Yeah, I played with it for aout a week until I posted, so I pretty much got frustrated and gave up for now....

Back to the dhcp issue....

 

[kojack96]

I am using rogers cable, and I am not too sure if they lock the MAC addresses.

I was thinking if I were to realese /all on my win 2k machine would that drop my MAC on rogers side?

I tried to bind the IP of my PC to the router but didn't work.
There are a few things I will try tonight.. I will try to sut then no shut the int with the binded MAC address to see if it works. If not then I will try to attach my PC and release the address then attach the router reboot the modem and try to obtain an address from my ISP..

I do have a funny feeling though that my ISP is somehow holding the MAC of the old pc.

Thanks everyone for the great replies. I will tell you what happened tommorow!

 

[Guest_imported]

There is a good article on this at cisco's web site.

http://www.cisco.com/warp/public/109/router_behind_cm_19268.shtml