Tom's Hardware > Forum > General Networking > Network General Discussions > force new IP
Ask the community Add a reply
Word :    Username :           
 
Retruglot   04-21-2002 at 05:18:34 AM

I am new to the networking game so I'm playing around with somethings to try to learn more about it... I figured out how to get into my cable modem through http, but I can't seem to make any changes (that I know of). My question is:

How can I force my Surfboard 4100 cable modem to let go of my IP address and obtain a new one? or is that controlled by the lease from the CISP?

My objective is to have my IP changed when/if I want to change it... I'm running WinXP and have changed the IP to another (simply upping the last three digits a coupla numbers) but it doesn't seem to work. As a matter of fact, I even put in the exact same IP, Subnet Mask, Default Gateway, DHCP Server, and primary and secondary DNS numbers but it wouldn't connect unless I let WinXP make the decisions...

Anybody care to school me?


Thanks,
Ret

Add a reply
Sponsored Links
Register or log in to remove.
Zlash   04-21-2002 at 05:46:05 AM
- 0 +

The cable company gives you the IP, not the other way around. You have to use that or you don't have access.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Retruglot   04-21-2002 at 03:19:10 PM
- 0 +

I thought that since it was dynamic I could let it go and a different one would come back?


Ret

Reply to Retruglot
Zlash   04-21-2002 at 04:13:57 PM
- 0 +

Yea dynamic enough to assign you the same IP everytime =), my cable actually gives out different IPs to different MAC addresses. So my router gets a different IP than when i hook up straight to the PC.

If you think it is otherwise, just reset the modem and find out if it's different.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Retruglot   04-21-2002 at 04:20:46 PM
- 0 +

Hehehe.. yea, that is my problem.. I've reset it and the same one comes back... I understand it has something to do with having a lease on it. Hmmm.. so, with what you know, I'd have to change the MAC address in order to get another? So that would mean changing the cable modem, eh? What about changing the NIC? or is that a whole other unrelated issue?


Thanks for your knowledge,
Ret

Reply to Retruglot
Zlash   04-21-2002 at 04:26:57 PM
- 0 +

No, just changing the NIC in the computer...that's how mine works anyway. I'll test mine out in a sec hehe.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Zlash   04-21-2002 at 04:50:57 PM
- 0 +

Yup it worked that time too, got 3 different IPs. 2 NICS and a router.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Retruglot   04-21-2002 at 04:57:50 PM
- 0 +

Yea, but I think the cable company only sees the router IP, eh?



Ret

Reply to Retruglot
Zlash   04-21-2002 at 04:59:27 PM
- 0 +

Not using the router.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Zlash   04-21-2002 at 05:00:13 PM
- 0 +

Or I should say not when I am using the NICs.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Retruglot   04-21-2002 at 05:11:56 PM
- 0 +

Hmm... so if I change my NIC it will change my IP?

Ret

<P ID="edit"><FONT SIZE=-1><EM>Edited by Retruglot on 04/21/02 11:12 AM.</EM></FONT></P>

Reply to Retruglot
Zlash   04-21-2002 at 05:16:15 PM
- 0 +

Depends on how your ISP handles it, I can only say for sure that it works for mine. Cox HSI.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Retruglot   04-21-2002 at 05:28:42 PM
- 0 +

Cool.. seems like a long way around the horn.. but I'll give it whirl after while and see what happens. Thanks for the schoolage.


Ret

Reply to Retruglot
jlanka   04-21-2002 at 05:44:42 PM
- 0 +

if you're just looking to play around, why not get a router? Then you can play to your hearts content.

<i>It's always the one thing you never suspected.</i>

Reply to jlanka
jihiggs   04-22-2002 at 06:46:08 AM
- 0 +

why do you want so bad to change your ip address? if you are worried about some one hacking you, changing your ip every couple of days isnt going to help you. get a firewall.

ccna+mcse=debt4life

Reply to jihiggs
Uncle_Astro   04-22-2002 at 09:15:17 PM
- 0 +

The reason why you get the same ip address when you reconnect with the same NIC is that the DHCP server (at your ISP) is retaining your NIC's built in MAC address. Real DHCP servers (unlike the versions found in cheap routers or within Windows) let their administrators control the lease and disconnection-timeout length's so they can allow you to disconnect and reconnect with the same ip for up to the lease time. Some high-end server NIC's will let you manually change a portion of the MAC address (not the whole address) but this feature isn't available on any single port NIC's that I'm aware of as it's almost never needed.

As far as choosing (guessing) your own new ip, you might get lucky and pick an address that is available and valid for your ISP's network, but you can't use only half of the DHCP client. That means that you might manually pick a good address, but you can't have DHCP assign the DNS addresses for you. You would have to set them manually as well. That's a bad idea unless you're certain of the exact addresses and know that they will never be changed.

"There are no mysteries with computers...just fix it you idiot!" (R. Warren 1909-1990)

Reply to Uncle_Astro
Retruglot   04-30-2002 at 01:59:16 AM
- 0 +

Thanks for the low down.. I wondered if other addresses had to change when I manually picked the next IP and it didn't work.

Well, as to "why do you wanna do this?" - Basically I am pretty comfortable breaking and fixing PCs, but I don't know anything about Networking... so when my IP was banned from a BBS (ezboard) for challenging the admin's Law I decided it was the perfect opportunity to learn and stroke my ego at the same time... hehehe.. however, I've not desired the ego stroke enough to change the NIC yet..

Which brings me to my next question.. can I put 2-3 NICs in the PC and just plug the cable modem into a different one to get a different IP? (since it will have a different MAC?). Or will multiple NICs freak it out?


Thanks for the lesson's people.. I always know I can find an answer here at the THG Community.


Ret

Reply to Retruglot
jihiggs   04-30-2002 at 06:00:17 AM
- 0 +

i think the ip is based on the mac address of the cable/dsl modem. some isp only want you to have one computer use the connection so they only allow one internal mac to get outside the modem.

you shot who in the what now?

Reply to jihiggs
Zlash   04-30-2002 at 08:04:46 AM
- 0 +

Mine gives me a new number per MAC as I said above =).


<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Zlash   04-30-2002 at 08:05:29 AM
- 0 +

No it won't wig out, you'll just have a little icon on your system tray saying it's not plugged in.

<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>

Reply to Zlash
Ask the community Add a reply
Tom's Hardware > Forum > General Networking > Network General Discussions > force new IP
Go to:

There are 1246 identified and unidentified users. To see the list of identified users, Click here.

Forum map
Bestofmedia Forum ©
2000-2009 Bestofmedia Group
Page generated in 1.179 seconds
Please mind

You are about to answer a thread that has been inactive for more than 6 months.
If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.

Add a reply Cancel
Sponsored links
  • Ask the community now
  • Publish
Ad
They won a badge
Join us in greeting them
  • 01:00 EChiasson won the Freshman badge
  • 01:00 Foxer57 won the Uniformed badge
  • 01:00 gregmo won the Freshman badge
  • 01:00 vishnuvamp won the Freshman badge
  • 01:00 whiz won the Freshman badge
  • 01:00 jconline won the Uniformed badge
  • 01:00 qiaoda won the Uniformed badge
  • 01:00 sykohedd won the Uniformed badge
  • 01:00 jundja won the Uniformed badge
  • 01:00 cnsftci won the Uniformed badge