DHCP failure

[Wesley Thielke]

I have a Presario 5000 with XP Home Edition connected to DSL via a Dlink DI-604 router. When I set up for DHCP, it fails to get an IP address. It works on another machine connected to the router and the router shows that the Presario was given an address. Previously was directly connected to the DSL modem and had ICS enabled. Also, if I assign a fixed IP address (192.168.0.2), I can't ping anything except the router, not even 127.0.0.1. When I do ipconfig/renew, it says it fails with a timeout. I get an address of 169.254.x.x.

[Lance Brown · Accepted solution]

First, is the NIC working? If you cannot ping 127.0.0.1 then the problem lies within the machine itself. Either the driver is wrong or something is wrong with the NIC.

What do you see when you do a
netstat ???r

What does the device manager have to say about the stratus of the NIC?

Lance

[Jon Finley]

MS suggests installing the latest Service Pack for XP.

http://support.microsoft.com/default.aspx?scid=kb;en-us;313896


MS also had a good article on installing and working with static addresses with ICS that might be helpful.

http://support.microsoft.com/default.aspx?scid=kb;en-us;309642


Jon

[Wesley Thielke]

netstat -r shows the 169.254.x.x address as the gateway.
I don't think it's the NIC itself, since it works when I use a static IP address (e.g. 192.168.0.2). The fact that the loopback ping doesn't work is still a mystery, but I don't think that's a reason to suspect the NIC, since loopback pings are usually just returned within the IP stack. The fact that ICS also uses the 192.168.0 network sounds interesting. I'm supposedly not using ICS anymore, but I'm thinking that there is some remnant around and there's a conflict with the router. On this theory, I tried assigning 10.1.0.1 to the router, but I still get the same result when I try to use DHCP. BTW, I have another XP machine where DHCP works fine, but I also can't ping 127.0.0.1. I'm going to check the XP service pack

[Wesley Thielke]

The device manager says the NIC is operating properly. I couldn't find anything wrong there.

[Ron Kinner]

If you can ping the router then the NIC and cable are good. When you do a static setup did you put it the gateway address and the DNS address. I use 2K and not XP but I expect
ipconfig /all
would still work. Go to the one which works and get the results of ipconfig /all. Then go to the bad one and put the same info into the TCP/IP setup but add one to the last octave of the IP address and don't forget the DNS, mask, and gateway. That should work. If it doesn't then remove TCP/IP, reboot and then reinstall TCP/IP.

I assume you are uptodate on your patches. XP needs a lot of them. http://windowsupdate.microsoft.com

Ron

[Lance Brown]

192.168.x.x is a public address space, just like 10.x.x.x and 172.16.x.x-172.31.x.x. 192.168.is just the smallest address range out of the three, so MS chooses that one. If netstat shows 169.254.x.x then that explains your problem. The NIC is using a default gateway that it???s not suppose to. You need to find out where this 169.254.x.x is coming from, as it is a private address. Does your ISP use that address space?

Lance

[Ron Kinner]

Lance,

The 169.254.x.x is just the default number that Windows uses when it doesn't get a reply from a DHCP server.

Ron

[Lance Brown]

Good job MS; use an address space that is set aside for special use. They better hope that it never gets used. I guess it would have been too much to ask that they used a public address space.

Lance

[Ron Kinner]

Lance,

Actually, tho they never said so in networking class I've ever taken, 169.254 is a legal address for just this purpose. From RFC 3330:

169.254.0.0/16 - This is the "link local" block. It is allocated for
communication between hosts on a single link. Hosts obtain these
addresses by auto-configuration, such as when a DHCP server may not
be found.

If you do a whois on it it comes up as blackhole and refers you to RFC 3330.

Ron

[Lance Brown]

You???re right, I was thinking about a different RFC. There are too many non-private address spaces. A full class B is not needed.

Lance