IP Configuration Error/Can't access internet with two macs at once

[hes792]

Hi, I'm very new to this, but I will try to be as detailed as I can.

Background Info:

• I connect to the internet wirelessly via an Airport Extreme and an Airport Express
• Between my roommates and I, we have one macbook, two macbook pros, and an iMac G5 desktop

The problem is as follows: whenever I try to connect to the internet with two computers at once I receive an error message. The error message states:

IP Configuration
99.141.60.56 in use by 00:23:6c:82:7c:07, DHCP Server 192.168.0.1

The only way I can connect to the internet is if one computer is connected, and all the other computers have their airport turned off.

Now, I've done some work and I understand the message, I just do not know how to fix it. "DHCP Server 192.168.0.1" refers to the server both computers are on, and "99.141.60.56" refers to the IP address both computers are attempting to connect to (which I know is a big part of the problem). "0:23:6c:82:7c:07" is the ID of my macbook (note: I received this message while using the desktop computer).

One last note: I have always been able to connect to the internet with multiple computers before a week ago when I began receiving this message. Also, I began receiving the messages right after my roommate used "Remote Desktop Connection" to connect to his work email and work from home. Is it possible they (they being my roommate's work company) set up some sort of barricade or something?

Thanks so much for listening and for whatever help I may receive!

 

[crewrules101]

first off, shut down all the computers. when they are all off, unplug both the airports. once they are off, wait one minute (litterally 60 seconds) then plug in the airport that connects directly to the internet. I am assuming that you are using WDS and one of the airports is functioning as an extender? then plug in the second airport after the first one shows a solid green light on the front of it. now turn on the computers. On the computers in system prefs>network>airport, make sure that all of them are using DHCP, and not DHCP manual address. they all should now be able to use the internet. if this dosen't work go into the airport base station that is connected to the internet and check to make sure that there are no MAC addresses assigned specific IP addresses (static-IP...). Hopefully this helps

 

[hes792]

Firstly, you are correct in assuming the Airport express is being used as an extender. Secondly, I did exactly as you said, yet I am still unable to connect with two computers. I have not tried looking for static addresses, as I am not sure what that means or how to do that.

Also, after attempting your solution, while using the desktop I received the same error message I had been receiving, however the IP address in use had changed. But the IP address it referred to was the same one the macbook was connected to (but it was different from when I originally received the error). I am not sure if that is significant, but I thought I'd say it anyway.

Thanks so much for responding!

 

[Mumford]

Sounds like you have your Airport set up in Bridge mode instead of "Share a public IP address" mode. Airport Utility -> Internet (button along the top) -> Internet Connetion (tab) -> Connection Sharing (towards the bottom).

 

[hes792]

Unfortunately, I am not in Bridge mode. I am encountering this error while in "Share a public IP address" mode.

 

[Mumford]

OK, so what's the range of IPs you have your Airport set to give out via DHCP?

 

[hmmfe]

The problem is as follows: whenever I try to connect to the internet with two computers at once I receive an error message. The error message states:

IP Configuration
99.141.60.56 in use by 00:23:6c:82:7c:07, DHCP Server 192.168.0.1

The IP address you have is a public and is owned by SBC. If you do have the Airport setup to "share a public ip address", then you should not be getting that address via DHCP. As you probably guessed, something is not wired correctly or something is mis-configured.

First troubleshooting step: Disconnect your internet connection from your Airport. Then, try to renew your lease. See what IP address you get (if any). Please report back the answer.

Also, can you describe or provide a drawing of how everything is connected together including your internet connection device (e.g. cable modem, dsl modem/router, etc.)?

 

[Jethryn Freyman]

You have both Macs using the same IP address.

 

[hes792]

Hey everyone, thanks so much for the help!

I fixed the problem.

I'm a little embarrassed to say what the problem was....

...the ethernet was plugged into the LAN port instead of the WAN port.


whoops