Jump to content

Welcome to Geeks to Go - Register now for FREE

Geeks To Go is a helpful hub, where thousands of volunteer geeks quickly serve friendly answers and support. Check out the forums and get free advice from the experts. Register now to gain access to all of our features, it's FREE and only takes one minute. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more.

Create Account How it Works
Photo

MAC Address list full?!


  • Please log in to reply

#1
Dozi

Dozi

    New Member

  • Member
  • Pip
  • 1 posts
Hello,
I'm a PC technician and we run a network here in the store through Adelphia cable. The cable modem connects directly to a WinXP Pro (SP2) machine and we share the connection via a 2nd NIC. After that, we go through a couple switches and throughout my workspace. Now, being a technician, I see a great deal of PC's (around 100 per month). Each one gets connected to the internet at one point or another through the switch. For PCs that aren't equipped with ethernet, I'll use a USB Ethernet adapter. Now here's whats happening:

Starting a couple of weeks ago, I started noticing that the customer's PC's were not acquiring an IP address from the DHCP. Instead they were given the dreaded Automatic Private IP Address. Because of this, they weren't able to connect to the internet, which is a serious problem. It slowly seemed to get worse and worse. Now, two weeks later, any PC that comes in a can NOT acquire an IP address from the DHCP and I always get (limited or no connectivity). The only PC's that work on the network are the ones that have been here for awhile. Now, the reason I suspect MAC address problems is because while none of the "fresh" PC's that come in will acquire an IP, I can plug in the USB Ethernet that I've been using for over 6 months now and it will work! I'm guessing that no matter what PC the USB Ethernet (Netgear FA120) is connected to, it retains the same MAC Address and therefore the Server (our WinXP Pro machine) recognises it as an old one and will easily give it an IP. However, any new ones that come in that it's never seen before it will just go into meltdown as it tries to acquire an for about 30 seconds then finally gives up and says "Limited or No Connectivity, unable to retrieve IP address", gives me an Automatic Private Adress, and the Internet doesn't work.

Now, most people will be quick to say "how do you know its not the ethernet in the PCs or the cabling?". Well, I know its not the ethernet because when I configure the TCP/IP settings manually, I can sucessfully ping the gateway and see all the other PC's on the network. I just can't access the Internet. Also, I have tried playing with the "net config server /autodisconnect" command and it doesn't help at all.

So, for anyone that has actually read all this, what I'm asking is if its possible for a MAC address list to fill up in Windows XP Pro? Because right now, the only NIC's that connect to the internet are the one's that were working prior to two weeks ago. If it is possible, how do you purge the list and start over (short of reformatting). Thanks for any help.

--
Dozi
  • 0

Advertisements


#2
DHooper

DHooper

    Member

  • Member
  • PipPipPip
  • 339 posts
Hello Dozi welcome to Geeks To Go,

It could be possible that there is a limted on how may MAC address there can be in a table. On Cisco Routers/Managed Switches they have memory that can be added more storage. I have not a clue on how to purge the MAC table, but you can buy a Router that has a built in switch and use that as the DHCP server, freeing up the Windows XP Pro computer from the service. Linksys routers are is a very good brand of networking hardware. Plus you will see better performace by using a router, and you can still plug the hubs/switchs that you have in to the ports in the router. Hope that this helps.
  • 0

#3
dmermal

dmermal

    New Member

  • Member
  • Pip
  • 4 posts
Umm dude...the one thing that I would check that you haven't said anything about is your DHCP scope. I'm betting that has been used up, if not let us know because to me that would have been the first thing I checked...

Derek
  • 0






Similar Topics

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

As Featured On:

Microsoft Yahoo BBC MSN PC Magazine Washington Post HP