Shutdown IP Release

[talfin1]

I'm looking for a way that I can have a laptop computer automatically release the IP address assigned to the PCMCIA NIC on shutdown. I currently have a script running on startup that releases the IP and then renews the IP. I will take either a Registry entry or a small software program that would run a batch file on shutdown only. This is needed so some weird routing issues can be taken care of for mobile users.

Thanks to you all in advance,

Talfin

 

[Herr Yunta]

If this is on your own network, just set the dhcp server to only lease the IP's for a short time, so that after the computer is gone, the IP is free to be used.

 

[talfin1]

Thanks for the response Herr,

This is not my network... I'm setting up laptops for my work network. The lease time is 4 hours. The routing conflict happens if they disconnect from the network, dial in to a regular ISP with the modem and then try to access a web server that happens to reside on the work network... because the NIC is still configured with the work network IP address, the IP packets are routed to the NIC to try to access the web server... not the modem and thus times out on the web page... I have created a work around where everytime the laptop is booted up and logged in, it automatically releases the IP address on the NIC and then renews it. If the user is not connected to the LAN, then the batch file will time out and Windows 98 will assign a 169.X.X.X address that won't cause the problem...

I'm looking for a more stream lined solution where the system doesn't have to wait for a time out... like releasing the IP address right on shutdown as either a registry entry or a software program that only launches other programs on shutdown.

Anyone know if such things exist??

Thanks,

Talfin

 

[CTR]

Does the network at work use private IP's? If so, add a persistent route for that network.

 

[Scarpozzi]

I'm lost here... So you're connected to the internet via modem on a laptop... You try to access the webserver on your network and you can't? But if you release the network ip, it works?? If that's what's going on, what OS are you running on these laptops? If they're Win95/98 PCs, PPP should override your NIC IP...even if you were still plugged into the network. It should have NO effect on trying to connect...but, ya never know... I'm curious about this, so if you don't mind let me know what's going on with it. Thanks.

Ryan

 

[talfin1]

Okay... here's a long one...

This is all that I know of the situation... The OS on the laptop is Win98se. The laptop is using a Xircom Realport modem/nic. All laptops on the internal network access a DHCP server to get their TCP/IP information. I know that the DHCP server uses a 4 hour lease. The webserver in question is also on the same network and is accessible from the outside Internet.

The situation is that you log onto the network with the laptop, so the NIC has an assigned address (ie: 158.200.70.69). Let's say that the website that we are trying to get to is 158.200.115.200. The user shuts down the laptop and drives home... he's lucky, only a 15 minute drive away, but he needs to access the webserver to do some other work that needs to be done. He turns the laptop on at home immediately when he gets home and dials into his local ISP... so he has a two different IP address's assigned to the laptop if you look at WINIPCFG. He has 158.200.70.69 and what ever the ISP assigned. When he tries to access the webserver (158.200.115.200) the webpage times out. You release the IP information on the NIC through WINIPCFG while still connected to the ISP. The NIC is now assigned 0.0.0.0. You can immediately connect to the website.

This situation happens with different ISPs. I've tested Concentric, Earthlink, even AOL. I know that it has to do with routing issues and have found a work around that I'm not happy with because of the time to run the script. I have a batch file running everytime the user logs into windows... the batch file first releases the IP information on the NIC and then renews it. The result of it when the laptop is hooked into the network is that it releases the IP 158.200.70.69 and then renews it back to 158.200.70.69. If it is not connected to the network, it releases the IP and then renews it to a WIN98 default of 169.254.x.x. This works, but I don't like the 1 minute delay for the system trying to find the DHCP server and them timing out. If I can release the IP information on the NIC on shut down, then I will not have to run a renew command... it will automatically do that on startup the next time. Changing the lease time on the DHCP server is also not a possibility.

Thanks for all of your attention on this so far...

Talfin

 

[Herr Yunta]

It sounds odd that the laptop is not letting go of its dynamically assigned IP address upon shutdown. I thought windows by default, used a dial up connection before a lan connection also. I have my home desktop on three networks at the same time and can use my dial up to get to our server on the other network with out trouble. Just brainstorming....