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IP address conflict using Linksys Range Expander

Posted on 2006-05-05
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I have just installed a Linksys Wireless G Range Expander WRE54G Ver 2 plugged into an ethernet connection that is ultimately wired through a hub to my Linksys Router (WRT54G ver 1 with latest firmware installed).  Not an easy install!  Hours on phone with Linksys.  I finally got it going, but when I take my laptop into range of the expander I get the message "Windows - System Error.  There is an IP address conflict with another system on the network".  Interestingly no problem when I am in range of my router.  I saw a post addressing this issue with a router.  Various suggestions made, such as the possibility of a 2.4 gig phone.   Indeed one is right near the expander.  I unplugged the phone.  No dice. Still the message. Another suggestion was that there could be an IP address conflict with someone in the neighborhood.  I checked and, sure enough, there is another  Linksys router (unprotected) in range of the Expander (but not in range of my router).  The neighbor has a two bar signal.  So now I am suspicious that the neighbor is the culprit.   How should a get rid of the conflict?  Should I reset the expander, the router - or both in order to reset IP addresses?  What is confusing is that if I reset the expander (which alone is in range of the neighbor) isn't it the ROUTER which would dole out the IP addresses? I am WEP encrypted (128 bit).
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Question by:ccrp
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by:Rob Williams
ID: 16619898
I would choose an entirely different range. Try to avoid defaults, use something like 192.168.254.254 This should be set on the main router. I am not familiar with the expander but usually it would be set to something in the same range, but a different IP such as 192.168.254.253  This will in turn assign all connecting devices an IP in the 192.168.254.x subnet. Note: this will not affect any WEP encryption configuration.
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by:ccrp
ID: 16619982
If I change the IP of the router will there be any IP issues with Comcast broadband (using a cable modem) - or any other devices on the network (four computers and a couple of print servers)?  I assume I just reboot them all and they will be assigned a new IP.

Do I need to reset the router at any point - or the expander?
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by:Rob Williams
ID: 16620005
Comcast would be on the WAN side. You want to change the LAN side, so no you won't need to change anything there.

When you change the IP of the router (and expander) it will usually advise a reboot is necessary. Just a "heads up", I find once in a while Linksys units when you change the IP and reboot they don't come back on line, they seem to hang. Not likely, but if that is the case give it a couple of minutes, then just unplug the power for 20 seconds. They always come back after that.

All you connected devices will need to obtain new IP addresses. If assigned manually/statically you will have to do those, the others, the DHCP ones, just reboot or at a command line (DOS Window) run:
 ipconfig  /release
 ipconfig  /renew
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M0b1us earned 750 total points
ID: 16620110
The answer is : no need to reset your router.
cause : it's useless in your case this is ip conflict cause by neighbor signal your laptop will automatically get connected to nearless router.
Solution : disable Automatically conenct to neighbor router to avoid this changes router again follow this instruction
Control panel -> Network Connections -> <Your Wireles Network Connection> Properties -> Change advanced Settings -> Wireless Networks -> 'enable' use windows to configure my wireless network settings and in preferred networks you will see the SSID of your network, Remove none of your SSID name if listed then klik Ok

Hope this help

M0b1us


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by:ccrp
ID: 16621567
It has now straightened itself out after resetting the expander once more while connected physically to the router (and doing an auto config and putting the WEP key back in).  I then had to re-enter I guess this time it only picked up the preferred networks.  No more conflicts.  Thanks.
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by:M0b1us
ID: 16621926
thanks fot the point

regards

M0b1us
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by:ccrp
ID: 16622670
Perhaps I was too hasty.  I did take M0b1us advice and was sure to exclude other wireless systems.  But he message has resurfaced about the IP conflict with another system.  Odd.  Does it come and go when some neighbor is firing up his system or turning it off?  I may need to try RobWill's advice.  However, my problem with this solution is that when I use a new IP on the router, I can't then access the expander - and don't know what address is going to get assigned to it.  I started down the road RobWill suggested and discovered this problem.  I suppose I could first give the expander an address using the to-be-given IP on the router.  Of course, I couldn't then reset or auto configure the expander - as Linksys had me do over and over.  It appears I wouldn't be able to get into the expander web page (as I have already seen).

What also doesn't make sense is that I have never connected to any other network in the area - protected or unprotected.  Is this a known issue with Linksys routers and expanders?

Could it be a problem just with the Linksys expander?  I will give RobWill credit if he gets back on this one.
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by:Rob Williams
ID: 16622726
M0b1us' recommendation is a good one and will help isolate networks but I don't see how connecting to your neighbor's network, though you don't want to do that, would cause an IP conflict. If you connect to your neighbors network you should simply get an IP in their subnet and away you go.
I was assuming your bases station, in this case the range extender is in the same subnet, which is very possible as 192.168.1.0 is by far the most common subnet. It could even be connecting to their gateway router rather than yours.

The reason you probably cannot connect is, once you change the IP on the main unit the IP on your PC changed and then you can no longer connect to the old subnet of the extender.
I would log on to the extender, change the IP to 192.168.254.253, the gateway to 192.168.254.254 (this is important), and leave the rest alone. It will probably request a reboot. Allow it to do so.
Then don't worry about the changes, move to within range of the WRT54G, log on to it using the old IP, probably 192.168.1.1 and change it's LAN IP to 192.168.254.254 leave all else the same. DHCP range needs to change as well but all Linksys routers I have seen will do this automatically when you change the IP. Reboot. After 3 or 4 minutes either reboot your computer or run;
ipconfig  /release
ipconfig  /renew
as you will need to obtain a new IP in the new subnet. Now you should be able to log on to either address using the new IP's

If you have problems with any of this it might be due to the computer automatically obtaining new DHCP addresses in the new subnets. If so you may want to assign static IP's temporarily to your PC to retain control while configuring. Also when configuring routers always best to use a wired connection when possible.

See how you make out.
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by:ccrp
ID: 16623534
I changed the IP on the expander, as per your instruction.  I then changed the router to the instructed address.  Unfortunately I am still getting the same message that there is a conflict - only when I am in range of the expander.  Even though I get the message, I can still get pretty good internet access.  I have another laptop I tried on the expander.  It was getting the same message.  Just now I started getting the same address ("Windows - System error   There is an IP address conflict with another system on the network") in an area that is covered by the router.  That's a first.

While I updated the firmware on the router, I assumed the expander was the most recent (from Jan 2005), but perhaps not.  I wonder if the problem could be with the expander - the firmware or something else.  I will try to check the latest firmware, when I can get a connection.

Any ideas?
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by:Rob Williams
ID: 16623557
Always best to have the firmware updated, but I am doubtful that is the problem.

I don't have one of these expanders to look at, but I assume the only DHCP server is the WRT54G, the expander just relays the DHCP service to extend the range. Make sure that the DHCP range you have created doesn't overlap the IP's of any static devices such as the expander itself. I am wondering if the problem is your own network. For example if your DHCP range was 192.168.254.240 to 192.168.254.250, and the DHCP expander's IP was 192.168.254.241 you might get an PC conflicting with the expander. You are aware that the expander must be a different IP than the router as well, right ?

Wouldn't hurt to post the results from running at a command line:
  ipconfig  /all

Then also post the IP of the router and expander as well as your DHCP range on the router.
For security reasons do not post the WAN IP of the router.
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by:ccrp
ID: 16624582
You are correct. There is no DHCP server for the expander.  I ran the IPconfig /all on my notebook sitting in range of the router.   Here are the results:

Ethernet adapter Wireless Network Connection:

        Description . . . . . . . . . . . : Intel(R) PRO/Wireless 2200BG Network
 Connection
        Physical Address. . . . . . . . . : 00-13-CE-0F-2D-FB
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 192.168.254.100
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.254.254
        DHCP Server . . . . . . . . . . . : 192.168.254.254

----------
Here is the expander info:

Firmware Version
    v2.01.10, Jan 13, 2005  

IP Address  192.168.254.253
Subnet Mask  255.255.255.0
Gateway  192.168.254.254

SSID Channel is 11  Wireless security is enabled

-------------------
Here is the router:

Local IP address:  192.168.254.254
Subnet mask:  255.255.255.0 (default option)

DHCP Server enabled
Starting IP address  192.168.254.100  (100 is a default option)
Max DHCP users: 50
Client Lease Time: 0
Static DNS 1:  0.0.0.0
Static DNS 2:  0.0.0.0
Static DNS 3:  0.0.0.0
WINS:  0.0.0.0


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by:Rob Williams
ID: 16625239
That all looks perfect. Running out of ideas but;
-I see your expander has the latest firmware. Does the WRT54G also have the latest firmware? I noticed there are numerous versions of the WRT54G but several of them have firmware upgrades that include addressing issues to repeaters such as the WAP54G, perhaps yours as well
-In the event viewer [ enter eventvwr in the Start/Run box] of the PC that gets the IP conflict message, see if you can find an error relating to that. Often when you get an IP conflict it will reference the IP and possibly more. It probably won't tell you much but worth a shot.
-Try a static IP in a different range. Manually set the IP, subnet mask and DNS servers on your network adapter, of the problematic PV, to something well out side your DHCP range just to see if there actually is a conflict or some sort of system error. Try 192.168.254.211  If by some chance this works try setting up a different DHCP range on the WRT54G, say 192.168.254.20 to 40
-There are several little tools that will monitor various connected user information such as ARP, IP, MAC, station name. Try the following. It is dynamic and keeps changing, so watch it until you get the IP conflict message, see if it shows at any point 2 different devices with the same IP. Also you can send an ARP request. Try doing so with your IP, and see "who" replies. By the way the "producer"/manufacturer may not always be correct.
http://www.nsauditor.com/network_tools/arp_cache_monitoring.html
-I Goggled your problem and interestingly, you are not alone with this problem and equipment combination.
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by:ccrp
ID: 16646976
Actually it was the expander that didn't have the latest firmware.  I have now updated that. At first I thought it was going to work.  Alas, no.  Doesn't help.  I am still getting the same message - and the connection on teh expander progressively gets slower.  Nothing in the event viewer is showing up that is helpful.  I had already tried a static IP when on the phone with Linksys.  I think I am ready to throw in the towel.  Obviously this is not working.  I am wondering if the fact that the router is an early make (ver 1.0, I believe) is the problem.  (Even though it has latest firmware.)   Would getting a different router help?  Any suggestions for a combination that is tried and true, that actually works?
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by:Rob Williams
ID: 16648016
I don't thing the fact that it is an older router would make a difference as far as the connection and IP goes, possibly related to connection speed. Although I have set up a couple of units for clients, I really couldn't recommend any "tried and true" units. Although not necessarily the most powerful or configurable, the Linksys are usually very stable and work well.

Is it possible to move the router and Expander to an isolated location in another building as a test? Bit of a pain I admit. You wouldn't need an Internet connection, just test the DHCP automatic IP assignment. It is possible you have a neighbor playing games, or has equipment interfering. Even the speed issue could be someone downloading large files on your network. You can eliminate that by turning on MAC address filtering and only allowing your MAC address.
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by:ccrp
ID: 16648674
When I pulled the expander out of the box I had used the setup program, which is probably not the most recent version of setup. I had problems with the setup disk, which prompted the lengthy call to Linksys.  Could the program have done something to the expander - or router?  I would think after firmware upgrades, all of this would be moot.  Just checking.

I do have another location and will attempt this.
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by:ccrp
ID: 16648756
Does the wireless channel used make any difference?  I have been using 11.
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by:Rob Williams
ID: 16648833
>>"Could the program have done something to the expander - or router?"
Extremely doubtful, it does not affect the firmware in any way, and do you actually make the browser entries or does the set up program. Regardless those 3 or 4 changes are quite visible, no hard programming changes.

>>"I would think after firmware upgrades, all of this would be moot. "
Absolutely

>>"I do have another location and will attempt this."
Let me know how it goes. It's very odd, I am quite curious.
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by:Rob Williams
ID: 16648862
>>"Does the wireless channel used make any difference?  I have been using 11."
Generally you change that as necessary if there are other devices interfering with reception such as cordless phones, or it could be other wireless routers. Definitely worth a try, sorry didn't mention that before.
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by:ccrp
ID: 16666196
I think I have figured out what was going on.  I was physically plugging the expander into a wired ethernet connection at the end of the router's range, figuring that I would then be able to boost better signal into the far reaches.  Seemed logical.  However, this appears to be what was causing the error message.  Apparently it was not designed for this purpose.  The wired ethernet connection on the expander appears to be only for hardwiring to the router for installation purposes.  The instructions from Linksys, however, are a bit confusing or equivocal.

It doesn't make sense that they would design it so you couldn't plug in to a wired connection - unless there is some setting I don't know about.  Ideas?

When I run the expander without being plugged in it functions - minimally.  It has extremely poor speed, so much so that it hardly seems worth the effort.  I have tried it in a variety of locations, but it doesn't seem to help.  Could there be some setup issue with the expander?

Would it make more sense to put a another wired router on the problematic side of the building and do a bridge?  Could the expander, if wired in, function with a bridge?
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by:Rob Williams
ID: 16668175
>>"The instructions from Linksys, however, are a bit confusing or equivocal."
That is usually an understatement  :-)

As I understand it the expander is specifically designed to re-broadcast a wireless connection without the use of a wired connection. Just by design and re-transmission, it will be a slower connection although I have never used one to say how much performance is lost. I would be surprised if they were with reasonable distance of each other than you would notice a big difference with browsing.

If you have the option of a wired connection you would probably be better of adding an "access point". That way you are getting a full 100mbps to the broadcast point, as well as only using a single wireless connection.
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