DHCP problem

[petelta]

ok, im back with the same problem ive had for the past 6 months but about every month I figure out another peice of the puzzle lol. i feel like im getting close to fixing it without buying a new computer hehe. ok well internet working fine yesterday for about a week, today turn on computer and it says limited local connection and I can't go on the web browser or do anything. I ipconfig /all and there is no ip address or DNS or anything. THis has happened randomly for the past 6 months. internet will not work for 3 weeks and work for 1. ok so this time around when it was working I wrote down all the ip address and DNS and so forth so that I could put the same numbers in manually when it stopped working. so I did that this morning and it went from limited connection to full connection. well it still didn't really work, there was no internet or anything. so i did an ipconfig /all and there it said DHCP Enabled............NO. and I have the DHCP number that was working 2 days ago but I can't find where to manually plug it in. Im just wondering what is the DHCP part of, my network card, the modem, router, what? and how can i fix this peice of crap. thanks

[doctorgonzo]

Because you entered a static IP address, DHCP is disabled. You really don't want to enter an IP address manually, since it is probably within the DHCP server's scope and there is a very good chance that the IP address you have will be given to another computer on your network, and that's a bad thing.

What version of Windows do you have? For Windows XP, go to Network Connections and right-click on your Local Area Connection, then select Properties. In the list of protocols and services, click on Internet Protocol (TCP/IP) and then click on Properties again. On the General tab, make sure that "Obtain an IP address automatically" and "Obtain DNS server addresses automatically" are selected.

[mbossman2]

Originally Posted by petelta Im just wondering what is the DHCP part of, my network card, the modem, router, what? and how can i fix this peice of crap. thanks

DHCP stands for "Dynamic Host Configuration Protocol".

This is the ability of a PC to sing out "I don't have an IP address" and then be issued one automatically by some device on the network. Now, this device, aka DHCP server, can take many forms: a router, a switch, a server or something else. The most common form a DHCP server takes is the router that acts as your gateway to the internet.

Now, a DHCP server has a "pool" of available IP addresses from which to pick. The server also remembers who got issued which IP address. The problem that doc pointed out is when the DHCP server assigns IP address "A" and someone has also manually entered IP address "A" into another machine. You then have 2 machines using the same IP address, this is what network managers, using highly technical jargon, refer to as "a bad thing". Each user on the network must have their own unique network address. If not, you have a problem and it can cause all sorts of havoc.

If you have a network with a DHCP server and also have an application or other device that requires a static (manually entered) IP address, you must select an IP address that is: one: within the same subnet and two: not be included in the pool of addresses that the DHCP server can pick from.

HTH.

Unless there is a very compeeling reason, DHCP is the easiest and best way of doing IP addresses.

[petelta]

thanks for the explanation, but what am i supposed to do about my situation. After this past 6 months of doing everything I can think of an dhave been told to do by many many people nothing works. i did have obtain a IP Address automatically and DNS server clicked but unclicked so that I could manually put in an address since my computer won't get one itself. The ip address is a different ip address that is assigned to teh other computer on my network, i checked that. how do i fix the DHCP when its not working.

[doctorgonzo]

What is your network setup like? What are the components?

[petelta]

a modem, and a router

[doctorgonzo]

What kind of modem and what brand? What brand and model router?

[glc]

petelta, we need specific specifications to help you. Vague generalities aren't enough.

Exact type of internet service including the name of the ISP, brand and model of modem, brand and model of router, how everything is interconnected.

[petelta]

k I have charter cable. All of my equipment they came in and set it up, my apartment complex has this service included in rent so it was already set up. My modem model number is 60678EU, I can't tell what brand, it doesn't say on it anywhere. And I forgot buy I have a Lynksys switch instead of a router...model number EZXS55W. I have already tried to use a router instead but its the same problem. A few things to mention before, I plugged my computer directly up to the modem with out the lynksys and there was still no fix and when I take another computer and plug it into my room it works just fine, leaving me to believe that its my computer.

[glc]

You cannot use a switch to share the output of a cable modem - you have to use a router. You have to get the MAC address of the ethernet adapter in the computer that does work and clone it into the router. The cable modem is keyed to the MAC address of the adapter in the computer it was originally set up on, that's why routers have a clone function. Some cable providers such as Comcast have an auto MAC reset procedure (remove power from the cable modem for a few minutes) but I don't know how Charter handles this.

[petelta]

I would get a router and use that but here is why i can't. The interenet provider set this up and won't allow us to add anything or change anything to it. and the interenet worked fine on my computer for a year until I reformatted it. so I have to use the switch.

[doctorgonzo]

Originally Posted by petelta The interenet provider set this up and won't allow us to add anything or change anything to it. and the interenet worked fine on my computer for a year until I reformatted it. so I have to use the switch.

Your ISP may not provide any support if you add a router, but you can certainly do this. If you want to share your cable internet between two computer, you need a router, period. A switch won't do it unless you pay Charter for another IP address, which is totally unnecessary.

[glc]

The only way to do it without a router and using a simple switch is 2 network adapters in the host computer and ICS.

[petelta]

how did it work before and why does it work every couple of weeks? and why does it work for my other computer when plugged in the same cable.

[glc]

Because it's issuing an IP to the first computer that comes up. You only get ONE IP at a time from it and it cannot deal with the second computer till a MAC reset occurs. Get a router or buy a second IP from Charter.

[petelta]

thats wasn't teh case though. For the year that my internet worked my roommates computer internet also worked. It didn't just give one IP it was giving us both a connection. And while his internet works just fine the whole time, my computer that I reformatted won't but my old computer will when I plug it into the same cable as my new computer.

[doctorgonzo]

Do you already have a second IP from Charter but you don't know it? The only way that you can get two computers to share a cable modem through a switch is if you have two IP addresses from Charter.

Go to every computer and open a command prompt (Start...Run, then type "cmd" without the quotes). Type "ipconfig /all" without the quotes and post back with the results.

[petelta]

Im almost positive that we have different IP's but I will have to double check on that when I get home from work. if they are assigned different IPs then what can I do to fix the problem?

[doctorgonzo]

If you do have two IPs from Charter, then you need to configure each computer with the correct IP instead of using DHCP. That only applies IF you actually have two IP addresses, though.

[glc]

my computer that I reformatted won't but my old computer will when I plug it into the same cable as my new computer.

Post the ipconfig/all result from the old computer, then connect the new computer and do the same.

Ahem - did you reinstall the network adapter drivers after reinstalling Windows on the new computer?

[petelta]

yes I installed drivers after reinstalling Windows. ok here are the ipconfig /all from my old computer which works in my room, my new computer which doesn't work in my room, and my roommates computer which works in his room.

My room Old Computer Interenet works:

Host Name: powercore
Primary DNS Suffix:
Node Type: Unknown
IP Routing Enabled: No
WINS Proxy Enabled: No

Connection Specific DNS Suffix:
Description: Marvel Yukon....
Physical Address: 00-11-D8-D5-12-2F
DHCP ENabled: Yes
Autoconfigure Enabled: Yes
IP Address: 68.190.57.174
Subnet Mask: 255.255.248.0
Default Gateway: 68.190.56.1
DHCP Server: 68.114.39.11
DNS Server: 66.168.240.35
24.177.176.35
24.178.80.35
Lease Obtained: blah
Lease Expires: blah

My room New Computer Interenet doesn't work:

Host Name: powercore
Primary DNS Suffix:
Node Type: Unknown
IP Routing Enabled: No
WINS Proxy Enabled: No

Connection Specific DNS Suffix:
Description: Marvel Yukon....
Physical Address: 00-11-D8-D5-12-2F
DHCP ENabled: Yes
Autoconfigure Enabled: Yes
IP Address: 169.254.185.228
Subnet Mask: 255.255.0.0
Default Gateway:

My roommates room Interenet works:

Host Name: stephen
Primary DNS Suffix:
Node Type: Unknown
IP Routing Enabled: No
WINS Proxy Enabled: No

Connection Specific DNS Suffix:
Description: Intel(R) Pro/100
Physical Address: 00-13-47-2E-21-11
DHCP ENabled: Yes
Autoconfigure Enabled: Yes
IP Address: 68.190.63.150
Subnet Mask: 255.255.248.0
Default Gateway: 68.190.56.1
DHCP Server: 68.114.39.11
DNS Server: 66.168.240.35
24.177.176.35
24.178.80.35
Lease Obtained: blah
Lease Expires: blah

[glc]

You have 2 IP addresses - and apparently you can't do 3. Try ipconfig/release on your old computer, shut it down, then fire up the new one, see what happens.

[petelta]

Ipconfig /release and restarting on new comp didn't work =(....

[glc]

http://www.softpedia.com/get/Tweak/N...nSockFix.shtml

Try ipconfig/renew on the new one after the old one is released and shut down.

[petelta]

ok the ipconfig /renew didn't work. then ran the WinSockFix program and still no internet.

[glc]

It almost has to be a MAC-related issue then. If you are still resisting using a router, call Charter for assistance.

[petelta]

I am all for using a router, the only problem is Ive told my apartment office and they said they can fine me for messing with the equipment. So I have a meeting with the manager of the place to tell him what I think and hopefully get it fixed. and I called charter and they are worthless at tech support, they just tell me to call my computer company because its their fault.

what exactly is a mac issue?

[doctorgonzo]

A MAC address is the physical address that every NIC has. Generally, cable modems are set up so that they will only work with one network card, by refusing to connect to any computers with a different MAC address. It's like the network card's serial number.

[glc]

Review the whole thread - I discussed the MAC issue already and how to get around it with a router.

[petelta]

thanks for all the help guys. here is how I fixed teh problem. I just purchased a new motherboard and Internet works fine now heh. computers can be wierd. thanks again