Stuck at the same IP!

[SavoyBlue]

I know this problem is going to probably blow minds; as I can't seem to think of anything other than my BIOS being altered by a cable modem or NIC card storing the memory and not releasing it. Ok, heres my problem... I have a home computer that will retain the same ip regardless of powering the device on/off, re-installing the TCP/IP stack, or throwing DOS commands like ipconfig /release, ipconfig /renew, ipconfig /flushDNS, etc... I've even tried re-installing windows to a blank HDD partition-- still with the same results. The modem type is a Motorola Surfboard 4220; which has a built in RFC IP to 'console' to the modem, everything reads 'success', and my DHCP server remains the same (normal, but why is it throwing me the same IP after a reboot, poweroff, or re-config?) Well, I'm guessing its the MAC address of the cable modem that it is seeing, BUT ... when i hook the same device up to another machine, it assigns a new IP with regular leases. That makes me lead to think its the correlation between the NIC MAC and the DTE MAC. The real weird thing is-- My IP lease will renew itself even if the machine is left on to the date of expiration... it just 'renews the same IP'. XP Home, XP Pro, and 2000 experience this. I've tried talking to the professional idiots at their tech. support center; but it just ends up with them NEVER doing a thing from their damn side--- even though they are my DCE! I also run Sygate Firewall, and have tried permitting and denying relay ports in which the TFTP boot file would be sent to me. Even through a fault route; I still get the same IP. At this point in time, I'm really open to suggestions on a recommended cable modem. I was also wondering if Cisco made any 'Cable Modems' and not just routers. I plan to eventually hook this PDC (with the SAME IP!) to a double looped NIC, a SOHO91 Cisco Router, and an unmanaged switch.

In theory, wouldnt it be possible to connect your coax into an old 10mbps NIC (with a coax port) with some type of DOCSIS software? I mean, why does a broadband connection need 2 forms of termination? just because they realize you could spoof a MAC on a computer? I mean, all a cable modem is just EEPROM, DOCSIS compliant modulation, and co-ax to ethernet converter for the Tx;Rx.

C:\>IPCONFIG /ALL
Windows IP Configuration

Host Name . . . . . . . . . . . . : excalibur
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : Yes

Ethernet adapter The Network DCE Module:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . :
Intel(R)PRO/100 M Network Connection
Physical Address. . . . . . . . . : [private]
Dhcp Enabled. . . . . . . . . . . : Yes
IP Address. . . . . . . . . . . . : 68.54.139.158
Subnet Mask . . . . . . . . . . . : 255.255.255.128
Default Gateway . . . . . . . . . : 68.54.139.144
DNS Servers . . . . . . . . . . . : 68.82.0.5
68.82.0.6

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . :
Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . :
FF-FF-FF-FF-FF-FF-FF-FF
Dhcp Enabled. . . . . . . . . . . : Yes
IP Address. . . . . . . . . . . . :
fe80::5445:5245:444f%4
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter 6to4 Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . :
6to4 Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : 44-36-8B-8B
Dhcp Enabled. . . . . . . . . . . : Yes
IP Address. . . . . . . . . . . . :
2002:4436:8b8b::4436:8b8b
Default Gateway . . . . . . . . . :
2002:c058:6301::c058:6301
2002:836b:213c::836b:213c
DNS Servers . . . . . . . . . . . :
fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter Automatic Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . :
Automatic Tunneling Pseudo-Interface

Physical Address. . . . . . . . . : 44-36-8B-8B
Dhcp Enabled. . . . . . . . . . . : Yes
IP Address. . . . . . . . . . . . :
fe80::5efe:68.54.139.139%2
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . :
fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Disabled


Can anyone tell me whats going on? Any help would be greatly appreciated.

 

[netwho]

I had a the same situation with my isp and I the ip I allways got was listed on a realtime spam blacklist and therefor I wasn't able to deliver emails with direct mx ;-(
Becasue I didn't got any help from the isp I changed my MAC address (easy with linux) and I got a new ip...
If you really want to go into the modem, have a look to solarwinds broadband edition (

http://www.solarwinds.net).

However without knowing the distribution servers ip and community string you might not get in and it's probalby not legal as well.
cheers, who


__________________________________
DOS -> Windows -> Linux -> FreeBSD
**** The evolution of a geek ****

 

[manarth]

IPs don't get generated 'out of no-where'.

When you use "ipconfig /renew". your machine asks for an IP address. It puts a DHCP request on the network saying 'give me an IP address please'.

If you didn't have a DHCP server, windows would assign a default address beginning 169.x.x.x.

You do have a DHCP server (your cable modem), so it assigns you the IP address it's been programmed to serve you with.

As it's operating in bridge mode, it will serve the IP address that your ISP allocates to the cable modem.

This IP address is determined by your ISPs DHCP server, and may well be 'static'.

Changing your MAC may not fix the problem, and will occassionally prevent you from accessing the internet (some ISPs reserve your access to one particular MAC address).

<marc> i wonder what will happen if i press this...[ul][li]please give feedback on what works / what doesn't[/li][li]need some help? how to get a better answer: faq581-3339[/li][/ul]

 

[SavoyBlue]

you seriously want some feedback on that? thanks for 'the help' ... but that was just insulting my intelligence; anyways, &quot;netwho&quot;'s response made the most sense and I probably do have a HFC MAC ID conflict; since I know the difference between static and dynamic setups. In a normal enviroment, any /renew command will consult the DNS entries in the ARP table (the reason for flushing the DNS cache); im not going to get into the technical details of SYN's, ACK's, and SYN +1 to the UID. The DHCP server IS NOT YOUR CABLE MODEM. It is an IP in the same CO->LocalLoop as the DNS (not to your machine nor the modem); and is accessable by anyone on the 'internet'.

You Said:
&quot;If you didn't have a DHCP server, windows would assign a default address beginning 169.x.x.x.&quot;

I Say:
&quot;False. You dont need a DHCP server to get an IP ... it can be manually configured without any DYNAMIC HOST CONFIGURATION PROTOCOL.... and just applied the same way as an address in a router would be, and anyways, i think you mean 196.x.x.x, 10.x.x.x, or actually (ANYTHING YOU WANT IT TO BE using WINS); i mean, thats the difference between public and private IP.&quot;

And 99% of all static IP's dont use DHCP; they just tell you the information to plug into TCP/IP properties so it doesnt want to renew a lease all of the time.


SAVOY BLUE

CCIE, MCP, MCSE, CIS (Information Systems)
Network Security Management

 

[Grenage]

I don't believe manarth was suggesting that your modem was a DHCP, nor do I see the relevance of SYN ACK packets to your question.

With regards to: &quot;If you didn't have a DHCP server, windows would assign a default address beginning 169.x.x.x.&quot;

This is correct too, if you have no DHCP and your machine is set to dynamic you would indeed get the default address.

Regardless, have you tried phoning your ISP to see if they always issue the same IP address to their customers.

 

[jimbopalmer]

My cable ISP gives me the same DHCP address forever unless I change what service plan I am on. (I suspect they cap all modems in a given range with the same file) What is unclear to me in all of this is why you would ever WANT a new IP address, (unless you were running away from iresponsible behavior) as having the same IP makes all remote access (PC anywhere, FTP, gaming) easier

I tried to remain child-like, all I acheived was childish.

 

[kittenhammer]

Though it does seem a violation of spec to have your machines maintain a DHCP address past expiry, there's nothing weird about being assigned the same address every time you renew.

Perhaps Comcast's backend systems provision IPs based on the pair of MACs from the NIC and modem... duplicate MACs do happen, and binding IPs based on a pair of physical addresses would be a tidy way of minimizing that issue...

It's possible your secondary location wasn't plugged into the same CMTS, and may have been assigned a different IP based on the local addressing scheme. *shrug*

>I also run Sygate Firewall, and have tried permitting and
>denying relay ports in which the TFTP boot file would be
>sent to me.

Won't do much when the TFTP boot file goes to the modem, not your PC... though I suppose you know that.

>I was also wondering if Cisco made any 'Cable Modems' and >not just routers.

Linksys does

>In theory, wouldnt it be possible to connect your coax
>into an old 10mbps NIC (with a coax port) with some type
>of DOCSIS software? I mean, why does a broadband
>connection need 2 forms of termination? just because they
>realize you could spoof a MAC on a computer? I mean, all a
>cable modem is just EEPROM, DOCSIS compliant modulation,
>and co-ax to ethernet converter for the Tx;Rx.

Thinnet and your television cable have different electrical properties, so you'd still need something between the two. The data transmission scheme over a cable system differs significantly from Ethernet as well... I'm not sure if you could program an Ethernet NIC to range for appropriate up/downstream frequencies! (You can buy internal cable modems, if you're really set on it... but I believe that extra layer between one medium and the other results in a nice bit of flexibility.)

>In a normal enviroment, any /renew command will consult
>the DNS entries in the ARP table (the reason for flushing
>the DNS cache); im not going to get into the technical
>details of SYN's, ACK's, and SYN +1 to the UID. The DHCP
>server IS NOT YOUR CABLE MODEM. It is an IP in the same
>CO->LocalLoop as the DNS (not to your machine nor the
>modem); and is accessable by anyone on the 'internet'.

You could really place DNS/DHCP servers wherever you wanted.

Also... DNS has nothing to do with ARP. I'm not sure if you're flustered or extremely confused... ARP resolves IPs to physical addresses, while DNS resolves domain names to IP addresses. DHCP clients don't rely on DNS... if they did, how on earth would they resolve the IP of their DNS server [which would need to be provided through DHCP...] without an IP themselves?

-former professional idiot kittenhammer

 

[SuzanneBBI]

I have a cable modem through Comcast. Until last Thursday, I've never had any problems (I changed nothing). Now I'm getting the 169.xxx.xxx.xxx IP address and can not renew it. Comcast tells me it's a known Microsoft bug...cannot find what I need to do to correct. Any assistance would be greatly appreciated. This isn't my forte.

 

[cadaveca]

ok...so i read all the posts here and none seem to reach the undeniable aswer to the question... your ip is the same as your original ip is assigned out by your isp....when you first registered with thier service, part of the process was you nic making a dhcp request on thier network...so with that in mind , how do they know that it is you?
BY YOUR MAC ADDRESS. by the ip that you had you are on comcast nd i know that you will be subject to the same ip for a long time, until the laser card in the comcast building is filled up to it's max of 200 customers.(there were huge problems with comcast customers using routers...when they got a new lease they lost connection...the router was set to static instead of dynamic)
the tftp file will affect your pc in no way...it is simply a configuration file telling your modem which frequency the network is being braodcast at and what the maximum resolution is(connection speed)
i don't understand why you want a new ip unless you were worried about security, in which case a simple little bit of nat'ing will keep you happy. nat'ing is using a router for those who don't know, well basically(some of u will yell i'm sure)

the only right answer to &quot;why?&quot; is: &quot;why not?&quot;

 

[SuzanneBBI]

Cadaveca,
I don't know or care that much about IP addresses--I just want my internet connection back on my other laptop. I do have a router, what do you know about the issues with a router? Keep it to kindergarten level...this really isn't my area of expertise...I just code.

 

[kittenhammer]

SuzanneBBI,

If you're receiving a 169.254.x.x address when you are connecting to the Internet through a router, your cable internet may be fine. Your router would then be responsible for granting your PC an address, not Comcast. If your PC has an IP address in the 169.254.x.x range, it is unable to contact a DHCP server to request an IP, so it is automatically assigning itself one from a specific range (this is a Windows feature known as automatic private IP addressing, or APIPA).

I assume the Comcast tech at least had you connect your PC directly to your cable modem to see if you got connectivity; there could be a problem with your router.

 

[manarth]

The 169.x.x.x address can be seen as an 'error' address - your machine is set to using DHCP (or in Microsoft terms &quot;obtain an IP address automatically&quot but is not able to communicate with a DHCP server. This isn't a Microsoft 'bug'!

Fixes[ul]
[li]check your cables (correct type: i.e. normally Cat5 patch cable for a PC to router connection)[/li]
[li]check you have link lights on BOTH ends of the connection (i.e. on the router and on the laptop's network card)[/li]
[li]you may have a corrupted 'winsock' - there is a repair tool you can download:

http://members.shaw.ca/techcd/VB_Projects/WinsockFix.zip

[/li]
[/ul]
SavoyBlue: &quot;99% of all static IP's dont use DHCP;&quot;
100% of all static IPs don't use DHCP. Ho Hum.

<marc> i wonder what will happen if i press this...[ul][li]please give feedback on what works / what doesn't[/li][li]need some help? how to get a better answer: faq581-3339[/li][/ul]

 

[jpm121]

Are they giving out CCIEs in the back of comic books these days?

 

[ObsidianGT]

SavoyBlue: &quot;99% of all static IP's dont use DHCP;&quot;
manarth: 100% of all static IPs don't use DHCP. Ho Hum.

Actually, Savoy is right. Your DHCP server can &quot;reserve&quot; IP address to a specific MAC address so that it will always get the same address no matter what, there for requiring you to have &quot;obtain automatic IP address&quot; enable, yet your IP address never changes once you connect to the DHCP server. (This is the way that some broadband companies &quot;statically&quot; assign you the same IP forever. Alternatively, you can manual assign your static IP using your ethernet properties, but as long as you use the same IP address that the DHCP server has reserved for you, you'll be fine.

 

[manarth]

The definition of DHCP is DYNAMIC Host Configuration Protocol.

Hence, if it's DHCP, it's not static. You may keep the same IP address, and to all intents and purposes appear to have a 'static' IP, but this is not a static IP in the Networking lexicon.

The distinction is because dynamic IPs (even if they don't change) require a DHCP service: if you can't reach the DHCP server, you won't get an IP address. Static IPs don't have this dependency.


<marc> i wonder what will happen if i press this...[ul][li]please give feedback on what works / what doesn't[/li][li]need some help? how to get a better answer: faq581-3339[/li][/ul]