IP Configuration error

[maxtrax]

When I travel to a certain hotel, I plug in to the high speed internet via ethernet. This has always worked fine, it takes about 15 seconds and I am on. Last time and now this time, I get an IP config error, and I cannot connect.... The error reads...

192.168.10.6 is in use by 0:6:25:1e:b2:56, DHCP server 192.168.10.1

I have no idea what to do, nothing seems to work. My ethernet connection works fine at other locations and the hotel has internet working on other computers.

Any ideas??

Thanks
Paul

[hayne]

The error message indicates that the IP address that your computer is trying to use is already being used by some other computer. The message tells you what the MAC address of that other computer is.

I'm assuming that you have your Network Prefs for Ethernet set to use DHCP - this means that your computer asks the hotel's DHCP server for an IP address.

The "address already in use" problem could happen if some other computer had set its IP address to 192.168.10.6 manually - i.e. without asking the DHCP server for an address. Then the DHCP server doesn't realize that that address is already being used and it gives you the same address.

The best solution is for the hotel to find out which computer is not doing the right thing in arbitraily taking that address instead of nicely asking for an address.

[maxtrax]

Thanks Hayne... I tried to do what you said but the hotel people have no clue. Anyway, I brought over one of my Airport Basestations and plugged that in, and it was given a different IP! 192.168.10.30, and it worked fine. Although, if I copy the settings from the internet pane of the Basetstation using the Airport Admin Utility, into the internet section of the ethernet tab in my PB, and switch it back over to the PB directly, it still does not work. And letting it get IP from DHCP, still gives 192.168.10.6 in the PB, but 192.168.10.30 in the Basestation everytime.

Why would the Basestation get a different IP than the PB? Why wouldn't that IP work in the PB itself? I really do not want to have to bring a Basestation with me when I travel, it just seems to make no sense.

Thanks!!

[hayne]

Quote: Why would the Basestation get a different IP than the PB?

The DHCP server (run by the hotel) remembers all the MAC addresses of machines it has interacted with in the recent past and tries to give the same IP address to the machine as it did last time.

Your basestation has a different MAC address than your powerbook and if the DHCP server hasn't seen this MAC address before, it just assigns it whatever IP address is available. Your problem is that the DHCP server is trying to be helpful in always giving your powerbook the same IP address.

Quote: Why wouldn't that IP work in the PB itself?

It would (as long as no other machine is using that IP address). But I don't think you have configured your machine to use that IP address - you have configured it to ask the DHCP server for an IP address.

Let's check one thing to make sure I'm not completely out to lunch. The MAC address indicated by the error message was: 0:6:25:1e:b2:56
Please check that this is not your MAC address - which is displayed in the Network Preferences panel as "Ethernet Address".

I'll try to see if I can find some way to tell the DHCP server to give you a different IP addres than before. Meanwhile, you could just try assigning your machine an IP address manually (e.g. pick the one that got assigned to your basestation) by setting the Network Prefs to "Using DHCP with manual IP address".

[maxtrax]

Well, my PB's address is 00:03:93:98:a8:ac, so it is different than the one in the error.

But, I did try to set the IP manually using all the info from the Basestation. I unhooked the Basestation and plugged in the PB directly via ethernet, and manually put in the settings from the Basestation that were working, and still nothing. I did not get that same IP Config error though, it just endlessly tried to connect and could not.

Thanks so much for all of your help!

[hayne]

Quote: But, I did try to set the IP manually using all the info from the Basestation. I unhooked the Basestation and plugged in the PB directly via ethernet, and manually put in the settings from the Basestation that were working, and still nothing. I did not get that same IP Config error though, it just endlessly tried to connect and could not.

Did you use the setting "Using DHCP with manual IP address"? For this you just type in the IP address you want - you don't specify the other info as that is still obtained from the DHCP server.
What did you mean by "endlessly tried to connect"? Did you mean the web browser couldn't connect to a web site?
You might want to try some tests using "Network Utility" (under Applications/Utilities) to do network testing in this sort of situation. E.g. try to "ping" some Internet host like www.apple.com

Back to getting the DHCP stuff to work better for you - you would like the hotel's DHCP server to give you a different IP address.
One way that might work is if you changed your "DHCP Client ID" in Network Prefs. (This is one of the ways suggested by the comments to this macosxhints article: http://www.macosxhints.com/article.p...30212063233111 )
Another way might be to use the "renew DHCP lease" command using the third-party "Cocktail" utility (see http://www.macosxhints.com/article.p...30317070459293 )

[maxtrax]

Yes, I did try DHCP using Manual IP. What I meant by endlessly trying was... iChat saying connecting forever, instead of giving me the cannot connect error, WeatherPop did the same thing trying to update, no error, and yes websites hit the 60 second limit and didn't work either.

When I get the Config error, none of this happens, it is just an immediate error in each App.

I did try using Cocktail to renew lease the last time I was here and it did nothing. I will try Network Utility tonight. I will check out that article about changing my Client ID as well.

Thanks again!!

[hayne]

Quote: I will check out that article about changing my Client ID as well.

No need to read the article (I was just giving the reference for credit and for other suggestions to try) - changing the client id is simply a matter of typing something (whatever you want - usually one word, no spaces) in the "DHCP Client ID" slot in Network Prefs.

[maxtrax]

I tried everything and there is just no way this server will not assign the IP that is already in use to my Ti 800! I brought a Ti 667 to hotel tonite and that one worked fine with another IP. I brought the Basestation back over and that works fine too. My Ti 800 will NOT work. There really has to be a way to either change the MAC address or make the server assign a different IP to it. Manually setting an IP does NOT work, requesting a new lease does not work either... Client ID etc... nada works...

Thanks a lot for trying. I stay here every month and that is why this is so important to me.

Paul

[hayne]

I'm still very curious about what is happening here.
When you try to assign an IP address manually to your PB 800, what happens? You say it doesn't work - but what doesn't work? Please describe the symptoms.

And here's two things to try just for curiosity. Please report what happens when you try these. You would type these commands in the Terminal.

ping 192.168.10.6

This sends a test stream of packets to the machine with the 192.168.10.6 address. It should go on for a bit, telling you how long (in milliseconds) it took, etc. If it doesn't do anything, you can stop it with control-C

arp -a

This should give you a list of all the IP addresses and corresponding MAC addresses that your machine knows. It will be interesting to see if the 192.168.10.6 address is in there and with what MAC address.

[womby]

Quote: Originally posted by maxtrax I tried everything and there is just no way this server will not assign the IP that is already in use to my Ti 800! I brought a Ti 667 to hotel tonite and that one worked fine with another IP. I brought the Basestation back over and that works fine too. My Ti 800 will NOT work. There really has to be a way to either change the MAC address or make the server assign a different IP to it. Manually setting an IP does NOT work, requesting a new lease does not work either... Client ID etc... nada works... Thanks a lot for trying. I stay here every month and that is why this is so important to me. Paul

the problem that is hitting you is that the dhcp server is insisting on giving you the same ip address ... but you already know this.

the reason you cant change is is because everytime you re-conect it is within the timeout for the lease.

when you return in a month the lease will have expired and you will receave a diferent address. if it isnt urgent now (and if you can use airport it isnt urgent) dont worry about it.

the lease has to be less than 30 days because otherwise the hotel would run out of addresses quite quickly.

you can plug in as much other hardware as you wish it will all get diferent addresses but that isnt going to help you today.

[xavierblue]

I realise this is an old post but I am getting exactly the same behaviour with my PB G4 running 10.3.9 in a hotel.

The only additional piece of information I have noticed is that when I click the 'Renew DHCP lease' button I get offered a new IP address but my PB still rejects it saying that it is already in use by another machine. The strange thing is that it cycles through about 4 ip addresses saying that they are all in use by the same mac address.

Also I happen to have brought a PC with me which managed to connect perfectly using on of the IP addresses my mac had previously rejected.

Any one else come across this and found a solution?

[themphill]

From xavierblue's description I suspect their is a rogue DHCP server on the network or a misconfigured router. I encountered the former in a hotel, possibly from a guest plugging in their own router. And I've also seen this problem (on Macs but not with Windows machines) when there is a router somewhere incorrectly configured to do ARP forwarding. There isn't much you can do, although sometimes switching between wired and wireless connections will get you connected.

[Yamson]

I had this same problem yesterday at my office -- I have used my iBook there for years, and then all of a sudden I had this problem. I found this Apple Tech Note that fixed it for me.

http://docs.info.apple.com/article.h...tnum=106286-en

Good luck!