IP and MAC Address changed?

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June 4th, 2004, 08:11 AM
moxnix

IP and MAC Address changed?

This one has me scratching my........head.

I connect to the internet via a D-Link wireless router that is the gateway to my cable modem. The address for my laptop is 192.168.0.100 and the MAC is 255.255.255.0, normally.
Tonight when I turned my laptop on, it would not resolve any url. I checked the connection and found a completly different IP and MAC address.
I unplugged the router and reset it, with no change. I rebooted and attempted to repair the connection thru the repair function, to no avail.
I am still showing a IP of 169.254.21.246 and a MAC address of 255.255.0.0 and not connecting to the internet.

I disabled the LAN connection and plugged in my wireless PCI card, and every thing works fine using it.

This has happened before, and I know I can correct the problem by restoring my computer to an earlier date. But this time I want to find out what the problem is, and what is causing it.

I get an error when I start my wireless up also. It says that "Autodownload can not connect". A image of the error is included.

Also the addy 169.254.21.246 resolves to this (using Sam Spade)

Quote:

06/04/04 00:13:00 IP block 169.254.21.246
Trying 169.254.21.246 at ARIN
Trying 169.254.21 at ARIN

OrgName: Internet Assigned Numbers Authority
OrgID: IANA
Address: 4676 Admiralty Way, Suite 330
City: Marina del Rey
StateProv: CA
PostalCode: 90292-6695
Country: US

NetRange: 169.254.0.0 - 169.254.255.255
CIDR: 169.254.0.0/16
NetName: LINKLOCAL
NetHandle: NET-169-254-0-0-1
Parent: NET-169-0-0-0-0
NetType: IANA Special Use
NameServer: BLACKHOLE-1.IANA.ORG
NameServer: BLACKHOLE-2.IANA.ORG
Comment: Please see RFC 3330 for additional information.
RegDate: 1998-01-27
Updated: 2002-10-14

OrgAbuseHandle: IANA-IP-ARIN
OrgAbuseName: Internet Corporation for Assigned Names and Number
OrgAbusePhone: +1-310-301-5820
OrgAbuseEmail: abuse@iana.org

OrgTechHandle: IANA-IP-ARIN
OrgTechName: Internet Corporation for Assigned Names and Number
OrgTechPhone: +1-310-301-5820
OrgTechEmail: abuse@iana.org

# ARIN WHOIS database, last updated 2004-06-03 19:15
# Enter ? for additional hints on searching ARIN's WHOIS database.

Any one have any suggestions?

Edit: this is windows xp home on a 1600 mhz mobil amd.
June 4th, 2004, 07:00 PM
phishphreek

That address it changed to is the "windows default ip".
(When you haven't been assigned one dynamically and you haven't set one statically.)
This can also happen if you are set to DHCP (dynamic) and you haven't included the MAC address in the ACLs on the router to enable it to connect.

I've had that problem before where XP didn't know which NIC to use.
This is probably what was happening.

When you disabled the LAN connection... you gave it no choice but to use the wireless connection.

If you can't get a dynamic ip address it is because you don't have a good connection (wired/wireless physical media not connected), or the DHCP server is acting up. You can always assign statically. If this is the LAN connection that is showing you that IP, it won't do you any good. You don't have any physical connection. (You are trying to use wireless... so there is no reason to have the LAN connection enabled)

IP: 192.168.0.100
subnet mask 255.255.255.0
Gateway 192.168.0.1 (router)

You can get the DNS server addresses from within the router. Find your WAN settings and then look for the DNS servers. Some routers will let you put the router address as the DNS and forward to the correct DNS servers. Not sure with your router.

Just so you know, what you are referring to is not the MAC address. That is the subnet mask.

The MAC address is a 48 bit hex number that is unique to your NIC.
(first 24 bits are for the manufacturer and the second 24 bits are your "card number")

You can find it by going to a CLI and typing

ipconfig /all

It will tell you all the current settings for the NIC(s).
June 4th, 2004, 07:40 PM
moxnix

Thanks for clearing some of that up for me phishphreek80.
But,

Quote:

When you disabled the LAN connection... you gave it no choice but to use the wireless connection.

I only enabled the wireless connection when the LAN connection wouldn't work. I completely disabled the LAN after the wireless was working. The wireless by the way is now showing 192.168.0.100 addy that the LAN used to get.

A couple of hours later I tried the LAN connection again and it resloved to 192.168.0.102, and is working fine again.??
( the 101 addy is assigned to the downstairs computer I share internet connections with)

Quote:

Just so you know, what you are referring to is not the MAC address. That is the subnet mask.

The MAC address is a 48 bit hex number that is unique to your NIC.
(first 24 bits are for the manufacturer and the second 24 bits are your "card number")

I actually did know that. I'll just blame it on having a 'grey haired' minute, and tactfully ignore my error.
June 4th, 2004, 08:23 PM
phishphreek

When you first start the computer, it will have that 169.x.x.x number.

If it hasn't received a IP address within a minute or so... you can "force" it.

from CLI (cmd)

ipconfig /release

That will expire and release your "lease" which was never there.

ipconfig /renew

That will send a manual request for an IP address.

I normally just assign the IPs manually when there are just a couple PCs.

Then you don't have to worry about problems like this.

Maybe you need to upgrade the firmware in your router? I'm just guessing here...