assigning a fixed IP to a T40P

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llama_thumper · #1 Post by **llama_thumper** » Tue Nov 02, 2004 4:34 pm

I have my router assign fixed IPs to PCs on my network. all the desktops willingly accept them, except for my two T40Ps - whether they connect via wireless or ethernet, they never take the IP assigned to them but some random one. it doesnt affect their ability to access the internet since I haven't enabled full access control (ie only those with the specific IPs assigned to be able to access the inet), but once I do that, they can't anymore.

any help anyone?
i have the newest access (3.3) as well as the newest wireless drivers that came with it. the ethernet ones are up to date too...

ZPrime · #2 Post by **ZPrime** » Tue Nov 02, 2004 4:45 pm

well, in order to assign fixed IPs, your router needs to know the MAC address of the machine. your thinkpads will have at least two mac addresses - one for the builtin wired connection, and one for the WIRELESS. make sure you're providing the right mac address for the connection type you're using. if you want it to have a fixed IP for wired as well as wireless, you'll need to assign TWO fixed ip's to the notebook as most dhcp servers don't allow you to reserve a single IP multiple times.

llama_thumper · #3 Post by **llama_thumper** » Tue Nov 02, 2004 5:34 pm

hi,

yup, have assigned the mac addresses... and i have separate IPs for each one, wired and wireless... and still nothing!

ZPrime · #4 Post by **ZPrime** » Wed Nov 03, 2004 11:42 am

hmm...

the other possibility is that you have a second dhcp server on your LAN that you don't know about. You've got a router, is there any chance that one of your PCs (or laptops) has ICS (internet connection sharing, found in w2k/xp) turned on? ICS makes the machine turn on a DHCP server; whichever DHCP server answers first is the one that the client will take its IP from.

puco · #5 Post by **puco** » Wed Nov 03, 2004 2:08 pm

Power up a packet sniffer and look if the DHCP packets from the DHCP contain the specified address, or if the MAC address is correct. Or you can look into logs of the DHCP server, to see what addresses are leased to what MAC addresses

llama_thumper · #6 Post by **llama_thumper** » Wed Nov 03, 2004 4:12 pm

@zprime - thanks for the tip, will check, but doubt it since the other PCs on the network accept their assigned IPs.

@puco - will do, would u be able to recommend any simple packet sniffer? i will also look at the dhcp/router logs.

puco · #7 Post by **puco** » Thu Nov 04, 2004 3:27 am

You can use ethereal or packetyzer. They are both free and can decode many protocols.

For both od them you will need to install WinPCap library

assigning a fixed IP to a T40P

assigning a fixed IP to a T40P

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