XP and DHCP Addresses

[Chris S Patterson]

Greetings all, I have a users that has Comcast @home. The modem provided
performs NAT and DHCP giving my user a private IP address and DNS for the
Comcast network.

When he comes into the office, his XP notebook does not request an IP
address internally. Instead it continues to use the IP address and DNS
Settings assigned from his Comcast Modem/Router. Incidentally both the
internal network IP address range and the range issued by his modem/router
are the same, 192.168.x.1-254. I believe the modem's DCHP server settings
can not be changed to a different IP address range


This creates a problem because his notebook is still using DNS settings for
Comcast when he is on the internal network he is having logon issues, can't
browse network resources, etc. because his notebook is polling Comcast DNS
instead of our internal AD Integrated DNS Servers.

Can someone explain in detail how XP handles DHCP assigned addresses? I am
use to Windows 2000 where if you network connection is unplugged, upon
plugging back in it automatically requests a new IP address. XP seems to
continue using the same IP addresses prior to disconnection.

IS there anyway to force XP to request a new IP if disconnected from any
network connection, home or office?


Thanks in advance for the responses

Chris

 

[Wesley Vogel]

You can do something with Hardware Profiles, but if this works for you, it
may be easier.

Try this...

Start | Run | Type: cmd | OK |
Type:

IPCONFIG /release

Hit Enter

When you see the prompt again...
Type:

IPCONFIG /renew

Hit Enter

If that works create a batch file.
Call it: IPCONFIG rel renew.bat or whatever.bat
Paste or type the following two lines, without the equall signs...

===============
IPCONFIG /release
IPCONFIG /renew

===============

He can run the batch file after he hooks up to the office network.

 

[Chris S Patterson]

Thanks for the reply.

I thought about the use of IPCONFIG even as a batch file. However I wish to
know why is it only the notebook out of 8 using similar remote connectivity
is doing this?

I am looking at a possible hardware issue, maybe? Still undecided.

Listen Group->

I have observed XP unlike Windows 2000 retaining the IP Addresses given to
it, even after being disconnected from the network via Ethernet, whether on
the local LAN or connected to Comcast. What I wish to know, is the behavior
I am seeing normal? How does XP Behave pertaining to a assigned IP Address
after disconnection and reconnection to a network? either local of Comcast?

 

[Malke]

Thanks for the reply.

I thought about the use of IPCONFIG even as a batch file. However I
wish to know why is it only the notebook out of 8 using similar remote
connectivity is doing this?

I am looking at a possible hardware issue, maybe? Still undecided.

Listen Group->

I have observed XP unlike Windows 2000 retaining the IP Addresses
given to it, even after being disconnected from the network via
Ethernet, whether on the local LAN or connected to Comcast. What I
wish to know, is the behavior I am seeing normal? How does XP Behave
pertaining to a assigned IP Address after disconnection and
reconnection to a network? either local of Comcast?

Actually, what I *think* is happening, is that the laptop is not using
Windows to handle the wireless networking, but rather is using Comcast
software. So his laptop *can't* easily make the network switch. From
your description of the problem, I think he has two choices:

1. Drop the Comcast modem/router combo and get Comcast to give him a
normal cable modem. Buy a wireless cable/dsl router like a Belkin,
Linksys, etc. Set up the home network like that and get a dynamic ip
address via dhcp from the router. In the wireless networking Advanced
settings, choose to allow Windows to handle wireless networking. If he
does that, then when the laptop goes to the office it won't have any
problem (once the SSID and WEP are entered) in connecting at the office
- or at Starbucks.

2. Use third-party software like Multi-Network Manager from Globesoft.

HTH,

Malke

 

[Wesley Vogel]

Malke may have an *excellent* point. Comcast is my ISP. I do not use any
of Comcast's software. I just did an ipconfig /all, pulled the power plug
on my modem (I own it, Comcast doesn't), did an ipconfig /all again.

The only info that was retained was...

C:\>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : mypentium450
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection :

Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : D-Link DFE-530TX+ PCI Adapter
Physical Address. . . . . . . . . : 00-0D-88-3B-A5-78
=====

None of the following information was retained:

Connection-specific DNS Suffix . :
Dhcp Enabled. . . . . . . . . . . :
Autoconfiguration Enabled . . . . :
IP Address. . . . . . . . . . . . :
Subnet Mask . . . . . . . . . . . :
Default Gateway . . . . . . . . . :
DHCP Server . . . . . . . . . . . :
DNS Servers . . . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . :
Lease Obtained. . . . . . . . . . :
Lease Expires . . . . . . . . . . :


Oops, have to power the modem backup to post this. ;-)

I would say that what you're seeing is not normal, and, as, Malke suggests,
he may be using Comcast software.