DHCP problem in OS X

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I have this weird problem! In OS X I can't connect to the internet. I have a LAN connection directly to my ISP and obtain an IP address through DHCP with MAC address authentication. In OS X I get this messege "my.ip.add.ress is in use by (some MAC address other than mine), DHCP Server IP .. .. .. ..". This happened today, hadn't had a problem before. I switched to XP with Boot Camp and don't have any problem! Why does this happen? I talked to my ISP a couple of times, and the second time when I was asked what OS I'm using I had to spell out Mac OS three times and I'm not sure the woman understood me! They couldn't help. Their DHCP has my correct hardware address, so there's no way any other MAC address can get my IP and everytime i press Renew in OS X I get the same messege '(My IP) is in use by ...'! What can I do?
 

blodwyn

macrumors 65816
Jul 28, 2004
1,148
1
Portland, Oregon
I have this weird problem! In OS X I can't connect to the internet. I have a LAN connection directly to my ISP and obtain an IP address through DHCP with MAC address authentication. In OS X I get this messege "my.ip.add.ress is in use by (some MAC address other than mine), DHCP Server IP .. .. .. ..". This happened today, hadn't had a problem before. I switched to XP with Boot Camp and don't have any problem! Why does this happen? I talked to my ISP a couple of times, and the second time when I was asked what OS I'm using I had to spell out Mac OS three times and I'm not sure the woman understood me! They couldn't help. Their DHCP has my correct hardware address, so there's no way any other MAC address can get my IP and everytime i press Renew in OS X I get the same messege '(My IP) is in use by ...'! What can I do?
If you have a direct connection without a router, then I would consider getting a router. In any case I would go through a power cycle of the broadband modem (and router if you have one) and then try again. I've heard that the modems remember the MAC address of what's connected to them, and don't let go until you cycle the power
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I'm not sure who's MAC address it is, I use one ethernet port and airport is turned off. This hasn't happened before. Last night the problem suddenly was gone! And today again it happened, and right now I don't have internet with Mac OS and I[m typing this in Windows again... Could it be some problem with the ISP? I don't use any broadband modem or a router right now.
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I'm thinking it's a problem with OS X. I tried resetting PRAM, safe booting, killing processes in Activity Monitor, removing built-in ethernet configurations, and still when I enter my IP manually or use DHCP, i get 'ip.. .. .. .. is in use by (some MAC address). DHCP server .......'! This MAC address it says is using my IP, doesn't belong to airport, or any other connection I have (there are also parallels connections which are turned off).
 

blodwyn

macrumors 65816
Jul 28, 2004
1,148
1
Portland, Oregon
I'm thinking it's a problem with OS X. I tried resetting PRAM, safe booting, killing processes in Activity Monitor, removing built-in ethernet configurations, and still when I enter my IP manually or use DHCP, i get 'ip.. .. .. .. is in use by (some MAC address). DHCP server .......'! This MAC address it says is using my IP, doesn't belong to airport, or any other connection I have (there are also parallels connections which are turned off).
Are you sure Parallels isn't hanging on to the connection? Something on the Mac side is hanging on to the MAC address, and Parallels would be a likely candidate.

How are you connected if you don't have a broadband modem of some sort?
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I could try to remove Parallels entirely. I am connected via LAN directly to my ISP.
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I removed Parallels and it still doesn't work:( What could possibly cause conflict?!
 

MisterMe

macrumors G4
Jul 17, 2002
10,650
29
USA
I have this weird problem! In OS X I can't connect to the internet. ...
For Internet connection questions, you should always give the name of your ISP and how you connect to it. That said, there is a well-known issue with connecting a MacOS X computer directly to a DOCSIS 2 cable modem after using the modem directly via another OS. The workaround is to do a "hard reset" for 30 seconds. Power-down the modem, count to 30, and then power-up. This forces your modem to get a new IP-address. The fix is to use a router.
 

Revelate

macrumors newbie
Oct 24, 2007
2
0
DHCP issue

It's highly unlikely that Mac OS X is the issue, and your ISP is probably being lazy.

Give them the offending MAC address that is shown as the conflict, and have them do one of two (or both) things:

1) Blow away your DHCP entry from their database and let you request another one (DHCP will automatically give your current lease back to you if you simply renew, I'm not certain OS X will do a full release).

2) Have them check in their network bridge tables for that MAC address. Should take any competent network engineer under two minutes to solve it.

Check your MAC address in boot camp, I suspect it'll be different based on what you're describing, and that someone has simply manually set the address you're being given, or the DHCP cycle has been broken, in which case if they left it at default it may be a few days before it gets fixed, up to 15 dependent on what their default lease time is.

The router doesn't make much of a difference: any DHCP client will attempt to re-request its IP at various points during the lease cycle (typically 1/2 time remaining, and then later again, etc) so if it's always on, it always keeps the same IP address.

Assuming their lease timer is longer than a day though (and it probably is), if you're on the Mac every night, you'll keep getting the same IP anyway.

Hope this helps.
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
Thank you for your replies!

I will call my ISP as soon as I get home after work.

Even if I told you the name of the ISP I doubt it would help because I live in Bulgaria.

I will ask them to do the things Revelate has written and I hope they do something. It's a pain not having internet in OS X and having to reboot and use XP for browsing!

In Boot Camp some months ago I manually entered the same MAC address I have in OS X in XP, so I could receive the same IP configuration., so it still is the same now.

As for manually setting the IP, I tried it. My ISP gave me the configuration to enter manually, and it works in XP. In OS X I receive the same error message 'my.ip is used by (MAC address)'. The same error but without 'DHCP server address:....'.
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I entered a new IP address just to see something, the only difference with it and my IP is that this new test one has the fourth digits changed. I got the same error! 'This.new.test.ip is being used by (the same old MAC address)"! What can I do!? Even if I call my ISP, I'm not sure what to tell them! Would a Tiger reinstall fix this?
 

saltyzoo

macrumors 65816
Oct 4, 2007
1,065
0
You entered an IP? Well that's your problem. If you want to use DHCP you shouldn't be entering an IP.
 

iPlm

macrumors regular
Original poster
Dec 17, 2004
104
0
Sofia
I was given my correct IP by my ISP, to try and enter it manually, but again I got the same error, i tried entering other IP than mine and got the same error, with exactly the same MAC address as before!
 

MacDaddyof2

macrumors newbie
Sep 16, 2008
1
0
Mac OS X Chronic DHCP problem

I'm running Leopard 10.5.4 and I am having the DHCP problem. It is in fact something with OS X that Apple needs to quickly fix. I have a wireless network and my Mac is the only one that cannot connect via DHCP. It has rendered my Airport Express useless as well as I cannot access it from the Mac. All of the discussions that I have read on this issue point to Mac OS X Leopard (any release). I am very tempted to downgrade to Tiger if it is not fixed soon. This occurs on many flavors of hardware new and old and various network connections wireless and cabled. Don't get frustrated with your ISP on this issue. It isn't their fault. I was laying blame on them as well. My PC, iPhone and my son's PSP connect just fine.:apple:
 

saltyzoo

macrumors 65816
Oct 4, 2007
1,065
0
I'm running Leopard 10.5.4 and I am having the DHCP problem. It is in fact something with OS X that Apple needs to quickly fix. I have a wireless network and my Mac is the only one that cannot connect via DHCP. It has rendered my Airport Express useless as well as I cannot access it from the Mac. All of the discussions that I have read on this issue point to Mac OS X Leopard (any release). I am very tempted to downgrade to Tiger if it is not fixed soon. This occurs on many flavors of hardware new and old and various network connections wireless and cabled. Don't get frustrated with your ISP on this issue. It isn't their fault. I was laying blame on them as well. My PC, iPhone and my son's PSP connect just fine.:apple:
Sorry, but if this were a generic problem with Leopard there would be 10's of thousands of people complaining. Including me. I connect via DHCP 5 times a day with Leopard and never have had a problem.
 

paininmymac

macrumors newbie
Nov 25, 2008
1
0
Perpetual motion mac

Mac's have problems too, we are experiencing this problem on our network environment with four macs and a windows server 2003 providing DHCP. I am told that this has happened before after connecting a particular type of email filter. Not sure why this would happen, but I did not witness it personally so thats all I can say about it.
We have about 100 clients up and running, mostly windows XP but flavors of Linux and various print servers are also working just fine using DHCP. Further I notice that if I use a static address I get an error saying that the address is in use with a particular mac address. If I input another static address I get the same error with the same mac address. I am using address's that I know are open and not associated with any computer. Further an IP address can be associated with only one mac address at a time so the fact that it comes up with the same mac for two different IP's within the 30 seconds it takes for me to change the Ip address indicates that it is a bogus error.
Furthermore I was able to get the clients up and running though I have not fully resolved the problem. By connecting the clients to a switch (one that is not connected to anything else besides the mac clients) I can input a static IP address without the error coming up and thereafter connect the switch to the rest of the network allowing the mac clients to connect to all network and INTERNET resources no problem.
This appears to be a problem with whatever protocol or check that is performed by the mac to verify unique address assignment, and as it has been pointed out here, it is unlikely that the type of DHCP server or network environment has anything to do with it. Unless iplm's ISP was using Windows servers to manage DHCP, which I tend to doubt. At present none of the macs are able to get an address using DHCP.
Has anyone come up with anything on this? In a moment I am going to have to disconnect the macs from the rest of the network and reset the IP config manually. Not something I want to do on a daily basis. I am not a mac user so any insight would be appreciated.
 

starboarder2001

macrumors newbie
May 5, 2009
3
0
I'm running Leopard 10.5.4 and I am having the DHCP problem. It is in fact something with OS X that Apple needs to quickly fix. I have a wireless network and my Mac is the only one that cannot connect via DHCP. It has rendered my Airport Express useless as well as I cannot access it from the Mac. All of the discussions that I have read on this issue point to Mac OS X Leopard (any release). I am very tempted to downgrade to Tiger if it is not fixed soon. This occurs on many flavors of hardware new and old and various network connections wireless and cabled. Don't get frustrated with your ISP on this issue. It isn't their fault. I was laying blame on them as well. My PC, iPhone and my son's PSP connect just fine.:apple:
I am running Leopard 10.5.6 and DHCP will not work on my Mac as well. I can verify that it is not the DHCP servers problem and also that it is not user error. Any one else having the same issues?
 

saltyzoo

macrumors 65816
Oct 4, 2007
1,065
0
Try disabling your software firewall and seeing if that helps. I've seen people get locked out by their firewall.
 

starboarder2001

macrumors newbie
May 5, 2009
3
0
Try disabling your software firewall and seeing if that helps. I've seen people get locked out by their firewall.
Im using ipfw, and I have been trying with it disabled so that eliminates a firewall as the problem. I have been hardcoding my ip since about a week after I bought my mac and im not sure what broke it. I have installed parallels, then removed it, then install vmware fusion. Other than that and updates it is right out of the box.

I will do more troubleshooting and let you know
 

Chetters

macrumors newbie
Jul 4, 2009
1
0
I had this problem where I suddenly could not get a DHCP address. Same network, but suddenly could not get an IP. Different machines could get an IP, 1 mac could not.

This is what I did that worked.
  1. Delete wireless service from "Automatic" location
  2. Turn off all firewalls
  3. Add Wireless service back
  4. Re-enable firewall

I think something got corrupted somewhere and it just had to be rebuilt.
 

starboarder2001

macrumors newbie
May 5, 2009
3
0
Actually i am using the IPFW firewall. I am allowing ALL outgoing connections; but blocking all incomming connections. I have to disable my firewall for dhcp to work. Why? It is stateful filtering, after an outgoing connection has been established it will allow in/out.
 

saltyzoo

macrumors 65816
Oct 4, 2007
1,065
0
Actually i am using the IPFW firewall. I am allowing ALL outgoing connections; but blocking all incomming connections. I have to disable my firewall for dhcp to work. Why? It is stateful filtering, after an outgoing connection has been established it will allow in/out.
DHCP uses a client-server architecture. The client sends a broadcast request for configuration information. The DHCP server receives the request and responds with configuration information from its configuration database.
http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol

The server can't receive a request if you are blocking all incoming connections.
 

DanielSosMac

macrumors newbie
Mar 3, 2011
17
0
Paris
preferences?

I had this problem where I suddenly could not get a DHCP address. Same network, but suddenly could not get an IP. Different machines could get an IP, 1 mac could not.

This is what I did that worked.
  1. Delete wireless service from "Automatic" location
  2. Turn off all firewalls
  3. Add Wireless service back
  4. Re-enable firewall

I think something got corrupted somewhere and it just had to be rebuilt.
I have a Macbook Pro having the same issue at the office and the house (different ISP's). Neither Airport nor Ethernet work in DHCP, Dns server addresses are empty by default. Do you know if there are also some Preferences to be deleted? anyway I'll try this solution.
 

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