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ip conflict on home network

Posted on 2012-03-21
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Last Modified: 2012-03-30
I keep getting a ip conflict warning on my home network - router, 3 hard wired computers  and one wireless printer. I suppose it is the printer that is causing the problem. I had it corrected for a while but now I'm getting the warning again. I did a search but all related questions and answers seem a little outdated.
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Question by:CAR141
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by:bigeven2002
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Hello,

On each of the 3 computers, open up the command prompt and type ipconfig and press enter.  Write down the IP address for all 3 computers.  If any of them are duplicates, then that's the issue.

On one of the duplicates, you can change it's IP address in network adapter properties.  If they are on Windows 7, below is link on how to change the IP address.

http://windows.microsoft.com/en-US/windows7/Change-TCP-IP-settings

If all 3 are unique, then the printer is probably the conflict.  You'll need to look at the printer documentation to see how to change its IP.
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by:Tymetwister
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If the IP's are getting automatically assigned, try changing them to static IP's.
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by:ltsweb
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Make sure the printer is static.

Log into your router that is handing out IP (ususally xxx.xxx.xxx.1).  If not, do ipconfig /all and look at the entry called dhcp server.

If you are using a Cisco/Linksys router - Under status, local area network, you will find a DHCP table.  This will show you which ip is assigned to which device.

If you have a combo of static and dhcp addresses on your network, change the dhcp server to start to hand out addresses higher than the highest static ip address.
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by:Fred Marshall
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Don't forget that the router also has one of the addresses....
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by:CAR141
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I checked all of the computers last night. The ip addresses were 192.168.2.1 (router), .2.2 (Windows 7 computer), .2.3 (Windows XP computer), .2.4 (Lexmark printer), .2.7 (Apple IMac) and I was not getting any IP address conflict messages.

Today I'm getting the IP address conflict message again - on the Windows 7 and Windows XP computers. I checked all again but they are the same addresses as last night. I changed the Windows 7 computer from Use the following IP address to Obtain an IP address automatically and now I no longer get the ip address conflict messages.

Does the IP address conflict message show up only on the hardware involved in the conflict or will it show up on all computers and printers on the network?

Any thoughts on why I sometimes get the conflict and sometimes have none?
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by:Fred Marshall
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What IP address was it assigned then?
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by:ltsweb
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You should only get the message on the conflicted devices.  You should find it in the event log and perhaps it will show you the Mac address.  

Did you check your router's dhcp table to see any other devices on your network?

I would also download ipangry scanner and scan your LAN for other ip devices.  Ex wireless tv, play station, neighbors stealing signal, phones, etc.

I would also suggest you do a fresh av scan.  I've seen viruses cause ip conflicts in the past.

You are getting close!
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by:CAR141
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I don't know how to find that. When I select obtain ip address automatically it isn't shown. This is the Windows 7 computer.
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by:ltsweb
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I mean machine address.  What kind of router do you have?  Linksys? Verizon? Comcast Smc?
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by:CAR141
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You're asking questions I don't know how to find the answers to. dhcp table??? Machine address??? My router is a Belkin G plus MIMO EA58B5. I've done AV scan and scanned with malware bytes. no problems.
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by:ltsweb
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Ok, sorry.  I asked for router name so I can tell you how to find out what is on your network.  I will repost shortly.

Please download angry ipscanner from Angryip.org. When you run it, you can scan your network to see how many devices are on your network.  It is fairly simple to use.  When you start it hit class c and scan.
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by:ltsweb
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For the Belkin routers try the IP address 192.168.2.1. Enter the IP address in a browser which will bring up the status page. Click DHCP Client List, on the left side under LAN Setup. You will be asked to enter the administrator's password which by default is blank. The list of DHCP Clients will show up on the right panel.

Copy and paste it.  Next time you get a conflict do the same thing and let's compare.  The machine address will be displayed.  Every device has its own unique mac address so we can find which two devices are bumping into each other.

Not sure if you told us, but are these devices hard wired or wireless?

Regards.
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by:CAR141
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I get all kinds of warnings about the ipangry scanner when I tried to run it. and now some other search BLEKKO or something has taken over my home page.
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by:ltsweb
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I hope you downloaded it from the site I gave you.  It does not have spyware.  I use it all of the time.  In the mean time, uninstall it.  Run malware bytes.  The belkin dhcp table will have to do for now.

Blekko is a search engine not a virus.

From blekko:

By default, downloading the blekko spam free search bar also changes your default search engine to blekko. When downloading the search bar, you should have a chance to choose what settings on your Chrome browser to change.



Here are instructions for changing these settings manually.

To change your homepage:

1. Click on the wrench icon to the right of the address bar. This should be the wrench for Chrome and not for any toolbar.
2. Click on the “Basics” tab on the left hand side.
3. In the section marked “Home page” make sure the radio button is checked for “Open this page:” (if you want New Tab page instead, click that radio button and skip to step 5)
4. Enter the URL of the homepage you’d like to use. Some common homepages are Google: http://www.google.com, Comcast: http://xfinity.comcast.net/, MSN: http://www.msn.com/, Yahoo!: http://www.yahoo.com/, AOL: AOL. If you need help finding your homepage, please email us at support@blekko.com.
5. Close your browser.
6. Re-open your browser.

To change your default search engine:

For PC/Windows:
1. Click on the wrench in the right hand side. This should be the wrench for Chrome and not any toolbar.
2. Click on “Options.” Make sure you are in the “Basics” tab.
3. In the Search part of the page, choose the search engine from the dropdown that you would like to use.
4. Searching in the address bar should use the search engine you chose now.
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by:Fred Marshall
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You find the current IP address by doing this:

Window key + R opens the "run" entry

Type: cmd <enter>

(or access the command line window from Programs / Accessories)

enter:

ipconfig <enter>

See the ip address, subnet, gateway for each interface.

What address did the computer get automatically?
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by:CAR141
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you said: . When downloading the search bar, you should have a chance to choose what settings on your Chrome browser to change. As you know they always do a pretty good job of hiding such choices and installing their own version of search engine, etc.
I'm using internet explorer. Just got this computer and haven't changed to Firefox yet.

ran the ip address thing as per your instructions,
Ethernet adapter local area connection: 192.168.2.2. Tunnel adapter isatap.Belkin didn't show anything. Tunnel adapter local area Connection 12 media disconnected. (don't know what media that would be.) Tunnel adapter LAN 9: doesn't show ip address lists IPv6 Address and Link-local IPv6 address.
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by:ltsweb
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Ok,  with regard to Blekko becoming your default search engine, are you able to remove it and go back to google or bing?  If not, I will send you instructions.  I believe when downloading the scanner, there was a choice to download the Blekko toolbar.

Next, did you log into the web console for your belkin router and go to LAN setup?  I would like to see the dhcp clients table to get a baseline of the devices on your network.

Then, run the angry ip scanner and scan the entire class c range from 192.168.2.1 through 192.168.2.254.  It should then give you a list of every active device on your network.

Please copy and paste those results.  Once you have a conflict, run the scanner again and we will find the device that has the conflict ip.

Regards.
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by:CAR141
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LAN > DHCP Client List
There are three wired computers connected to the Belkin router and a wireless lexmark printer. It's easy to see the ip address of the printer. it is 192.168.2.4 and I have never found that it has changed.

I'm wondering if the apple doesn't have a wired and wireless connection both trying to run. The iMac had a message of a conflict with its 192.168.2.2 address this morning but everything still works. maybe it switches to another address?? or from the wired to wireless connection if there is a conflict??? My windows 7 had both wired and wireless connections until I shut off the wireless.

Here is the dhcp list. it does show two iMac connections. It shows Allens iphone, which may be connected wireless since the phone is nearby???  it doesn't show the xp computer which is a wired connection, doesn't mention the printer.
        
This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address       Host Name       MAC Address
192.168.2.2      Allens      38:60:77:A8:97:CC
192.168.2.7      Janets-iMac      3C:07:54:0C:8B:30
192.168.2.6      Janets-iMac      E4:CE:8F:65:3B:8E
192.168.2.9      Allens-iphone      F0:CB:A1:64:D8:7F

I have other things to do today so will not get back to this for a while. I will do the angry ip scan when I get time and let you know.
Thanks.
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by:CAR141
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This is what I got after shutting down the xp computer and turning off the iphone

  LAN > DHCP Client List

        
This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address       Host Name       MAC Address
192.168.2.2      Allens      38:60:77:A8:97:CC
192.168.2.7      Janets-iMac      3C:07:54:0C:8B:30
192.168.2.6      Janets-iMac      E4:CE:8F:65:3B:8E
192.168.2.9      Allens-iphone      F0:CB:A1:64:D8:7F
192.168.2.8            00:26:B0:98:34:D9
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by:ltsweb
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I am thinking one of your mobile devices connected to the web is causing the issue.  I think you should do one of my earlier suggestions and in the Belkin Router make the DHCP range 50-100.  Do not start it at .2 which is how it is configured now.

Go to Lan Setup, DHCP, and change the range from .50 to .100.



What is happening is that one of your wireless devices is conflicting with one of your wired devices.  Once you get the conflict, do the ip scan and the dhcp table and we will have it narrowed down.


Regards
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by:CAR141
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Can you tell me why the DHCP client list doesn't show all the computers connected to the router? Here is what is shows now with the win7, iMac computers being used on the internet and the wireless printer working and no iphone anywhere around here? I don't know what the 2.5 is about. Usually, if the iMac is being used it is listed as iMac under host name.
LAN > DHCP Client List

        
This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address       Host Name       MAC Address
192.168.2.8      Allens-iphone      F0:CB:A1:64:D8:7F
192.168.2.9      Allens      38:60:77:A8:97:CC
192.168.2.5            00:26:B0:98:34:D9
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by:CAR141
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I might mention that you need to describe what angryip does, or does to your computer, when you run the exe. Maybe it is totally safe but it is totally SCARY. What is its connection to Chrome?

As I mentioned earlier I started to run it and stopped when i got the virus warning but it still added its search page as my home page. I had downloaded it from CNET which used to be pretty safe. Anyway, I got back to my home page and deleted Blekko. There were other files that apparently downloaded with it that I tracked down with Malware bytes and my antivirus and got rid of.

So then I downloaded angryip from the page you said to. When I ran it. Malware bytes said NO! But I bypassed it and ran it anyway. Every page is a add this, add that, this is something you really need, etc. Again - SCARY! I unclicked everything as I went through and toward the end there was something that seemed to be set up so that you had to accept it. I finally quit again. Even then I had the Blekko search engine again, some other program, and one that was for translating from one language to another or something. I have removed all, ran Malware Bytes again and my antivirus again and so far as I can tell everything is back to normal. Angryip, as a cure, is worse than having ip address conflicts!
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by:Fred Marshall
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Well, it looks like the DHCP server in the router is set to provide IP addresses starting at .1 or .2.  And, if you have any static IP addresses, they may be in that same range.

Just to make sure, use IP addresses for static assignment that are well outside the DHCP range.  You can access the router through a browser at 192.168.2.1 for an address in place or a URL.

You can see the DHCP settings in the router.  Normally they are set to start at .100 or .101 and have maybe 50 addresses.  So .100 to .149 would be an example.  Having them in the low range like .2 to .51 with 50 in the range seems a bit odd to me.  Anyway, you have the choice and I'd start at .100 and have 50 .  Then all the static addresses can be .1 for the router, .2, .3 etc.
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by:CAR141
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fmarshall
attached are some dhcp client lists I had early this morning.

you wrote: You can see the DHCP settings in the router.  Normally they are set to start at .100 or .101 and have maybe 50 addresses.  So .100 to .149 would be an example.  Having them in the low range like .2 to .51 with 50 in the range seems a bit odd to me.  Anyway, you have the choice and I'd start at .100 and have 50 .  Then all the static addresses can be .1 for the router, .2, .3 etc.

What would I change exactly to get those ranges? Do you mean IP Pool starting address 192.168.2.1 and IP Pool Ending address at 192.168.2.100 ???
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by:CAR141
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Here are more LAN > DHCP Client Lists with various computers, a kindle, etc on the internet.

It looks like the iMac is connected both wired and wireless so should one of those be shut off?
       This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address      Host Name      MAC Address
192.168.2.6      Allens      38:60:77:A8:97:CC
              




LAN > DHCP Client List
       This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address      Host Name      MAC Address
192.168.2.6      Allens      38:60:77:A8:97:CC
192.168.2.7      android_36c24886b75249c4      F0:A2:25:C0:97:DE
              




LAN > DHCP Client List
       This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
LAN > LAN Settings
              You can make changes to the Local Area Network (LAN) here. For changes to take effect, you must press the "Apply Changes" button at the bottom of the screen.
               
       IP Address >        .  .  .  

       More Info

       ________________________________________
       Subnet Mask >       .  .  .  

       More Info

       ________________________________________
       DHCP server >       On  Off

       The DHCP server function makes setting up a network very easy by assigning IP addresses to each computer on the network. It is not necessary to make any changes here. More Info

       
       IP Pool Starting Address >        .  .  .  

       IP Pool Ending Address >       .  .  .  

       ________________________________________
       Lease Time >       
       The length of time the DHCP server will reserve the IP address for each computer.
       ________________________________________
       Local Domain Name >
( Optional )       



 
IP Address      Host Name      MAC Address
192.168.2.6      Allens      38:60:77:A8:97:CC
192.168.2.7      android_36c24886b75249c4      F0:A2:25:C0:97:DE
192.168.2.8      Janets-iMac      3C:07:54:0C:8B:30
192.168.2.9      Janets-iMac      E4:CE:8F:65:3B:8E
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by:Fred Marshall
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It appears that the DHCP server is putting out addresses that could well overlap with other things.  It's a little strange to have DHCP addresses starting at .2.  And, oh my, what if it starts at .1 ??  I would set the DHCP range to start at .101 and give it maybe 50 addresses.  So, that would be .101 through .150.  Then the static / manually entered addresses can start at .2

And, of course, don't use manual entries in the range .101 to .150
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by:ltsweb
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The belkin won't let you start at the router address. Based on the earlier comments, it is recommended that you:

1) Login to the Belkin router and under DHCP set the range starting at 50 and ending at 100.
2) Do not have your Mac connect BOTH on wired and wireless -- pick one or the other.
3) Set the PC's to static IP address (recommended but optional) for .5, .6
4) set the printer to static ip address (recommended but optional) for .10


You really should start with putting the DHCP range higher than the highest static IP address!  That is the most important part.

Keep us posted.
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by:CAR141
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Ifmarshall and itsweb: you are both telling me to set the DHCP Range at some numbers. In what  box to I put those numbers?
If I'm looking at the right place it now says

      IP Pool Starting Address >       . . . 192.168.2.5
        IP Pool Ending Address >       . . . 192.168.2.100

with each group of numbers in its own little box.
        
itsweb wrote change the DHCP range to start at 50 and end at 100. Where do I put the 50 and where do I put the 100?  

Ifmarshall confused me by writing "It's a little strange to have DHCP addresses starting at .2."  What does that mean?
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by:ltsweb
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IP Pool Starting address, make it 192.168.2.50
IP Pool Ending address, make it 192.168.2.100

As for "strange" it would be strange and almost impossible for it to start at .1.

DHCP is handing out ip addresses to each device on your network and an expiration date.  In other words, it tells the device you have this address 192.168.2.50 for 7 days.  After 7 days the device asks for another one.   It by default does not hand out the same ip address twice within that time range.

Your issue is that a device is getting an ip address and then the dhcp server is handing the same one again.  It could be caused by you rebooting your router, a device holding on to its ip address longer than it should, or having a static ip address inside of the range of the dhcp server.

That is why we were suggesting you do the following:

1) set the dhcp server above the highest static ip address on your network
2) check the dhcp table on the router to see what devices are using Dhcp and discover devices you didn't know existed (such as iphones, TV's, WiFi scales, or other wireless devices).
3) Scan your network using an ip scanner when you get a conflict to see what devices are on your network and which ip address they have -- then compare the base line dhcp table to discover if two devices are holding the same ip address.  (I see that this may be complicated, but it is a good plan).

If you are constantly rebooting your router or it is rebooting on its own, then this may be the issue that is causing the conflict.  It also could have something to do with the same computer connecting on wired and wireless at the same time (in windows networks this would cause an ip conflict message for sure).

Hope this helps!
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by:Fred Marshall
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There will be a section in the router control interface that is likely labeled DHCP.
You've already found it.  That's where either a starting and ending address will be OR a starting address and a number of addresses - amounting to the same thing.

Normally the router is at .1 i.e. 192.168.2.1.
Normally the subnet mask is 255.255.255.0 or is stated as /24.  Both mean the same thing.
If this is the subnet mask then there are 254 addresses available in the subnet:
192.168.2.1 to 192.168.2.254.
As above, normally the router will take up 192.168.2.1.
That leaves 192.168.2.2 to 192.168.2.254.

Your DHCP starts at 192.168.2.5 and ends at 192.168.2.100.
That's fine as long as you understand that .5 to .100 is now "assigned" for this purpose and there should be NO static addresses assigned in this range.

So, as before, I would enter the starting address to be 192.168.2.101
and the ending address to be 192.168.2.150.
That's just a choice.  Whatever choice you make is fine.
That's 50 addresses for the DHCP server to lease out.
That leaves 192.168.2.1 to 192.168.2.100
and
192.168.2.51 to 192.168.2.254
for manually entered / static IP addresses for devices on the network.

Just don't let these notional assignments overlap and you should be OK.

It's a bit more "normal" to see .2 up through .49 not be in the DHCP pool or range or scope so that the low numbers are available for static addressing.
So, whoever set your router up started the pool at .5 and you still have .2 through .4 for static and then everything from 192.168.2.101 to 192.168.2.254 also for static.
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by:CAR141
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I don't know all about how Experts-exchange works. I know there is sort of a competition between experts to get credit for answers, but maybe you need to read each others answer posts. For someone like me who is no expert or even close getting advice that seems different is confusing. Maybe it doesn't matter which of these I use but what is the difference between the numbers two of you have suggested?

IP Pool Starting address, make it 192.168.2.50
IP Pool Ending address, make it 192.168.2.100
AND
IP Pool Starting address, make it 192.168.2.101
IP Pool Ending address, make it 192.168.2.150

If it makes no difference which of these I use then I'll just pick one.

TO ADD a related QUESTION, I guess it makes no difference whether I disconnect the wired or wireless iMac connection, the iMac will still go through the router to communicate with the wireless printer????  Is the starting address 192.168.2.50 suggested because the wireless printer address is192.168.2.4 and that may be a static address?
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by:Fred Marshall
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I did try to be clear.  I did say:
"That's just a choice.  Whatever choice you make is fine."
But, yes the number ranges used as examples were different and perhaps that was a bad idea.  On the other hand, it gives you more examples of what would work.

Sometimes on EE, one will try to answer in a similar way if they believe they can add some level of understanding.  It's generally not so much competition for points but a real effort to provide information that's useful and understandable.    So, I hope all of these posts have been helpful.
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by:ltsweb
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I agree with FMarshall, we are just trying to help.  Although I imagine there are people that will try to offer the same advice.  As you can see, I originally suggested that you change the range in the beginning as did FMarshall.   I bet he and I either posted at the same time range or we didn't read each other's range.

Pick your favorite number 50-100 or 101-150.  Either way both will work.

As for mac question, always disconnect wireless!  Wired is much faster and more reliable of a connection.

As for points, since I am over 4 million points shy of leader, I am not that worried.  I like the practice of diagnostics as well as getting satisfaction of solving problems.  I would bet FMarshall feels exactly the same.

Hope this helps.
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by:Fred Marshall
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As a general rule:
Typical subnets have 256 addresses of which the first one and last one are used for the network address and the broadcast address.  Everything in between you can use.

So 192.168.2.0 is your network address
      192.168.2.255 is your broadcast address
And, most often and in your case, 192.168.2.1 is the gateway / router address.
So:
192.168.2.2
to
192.168.2.254
are all available for computers, printers and other things on your network.

Most of the time we like to "assign" blocks of these addresses for specific purposes.  In doing so we also like to leave some "margin" around those blocks for future growth or for new blocks we might want to "assign".   "Assign" here means on a list or in your head.

So, we might assign a block for DHCP purposes that has 20, 25, 40 or 50 or 100 contiguous addresses and starts at wherever you like.  It can be at .2 or .5 but most often is chosen to be at .50 or .51 or .100 or .101 just so the DHCP block is clear in your head into the future.

These examples translate respectively into ranges or scopes like:
192.168.2.2 - 192.168.2.21 with 20 addresses
192.168.2.5 - 192.168.2.24 with 20 addresses
192.168.2.50 - 192.168.2.69 with 20 addresses
192.168.2.50 - 192.168.2.99 with 50 addresses
......
192.168.2.51 - 192.168.2.150 with 100 addresses

Then you might "assign" 50 addresses for "static" or manual entries.
That might be .2 to .51.  or it might be .200 to .249.
Just so it doesn't overlap with your other assigned block for DHCP.

Then you might consider other addresses as useful and available for "everything else" like testing for example.  

Just like contiguous apartment numbers ....

I hope this helps a bit.
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by:CAR141
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I appreciate your help and didn't mean that I was accusing anyone of anything. I guess it's that when i don't know the answer I want make sure I don't do something that will screw everything up.

Let me figure out the iMac thing (wireless connection) and then I'll get back to close this out.
Thanks.
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by:ltsweb
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Just turn off airport on the Mac using the icon at the top right that looks like radio signals.  Are you still getting ip conflicts?
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by:Fred Marshall
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Turn off ipv6 on all the computers.  Just use ipv4.  See if that helps.  I can't imagine why but it's worth a try.  Maybe the conflict is an ipv6 address is what I'm thinking.

In windows, go to the network interfaces / Properties / remove the checkmark on Internet Protocol Version 6 (TCP/IPv6).  I've never seen this hurt anything and I have, on occasion, see it help.  So, it should be quite safe to do.

******

Also, I notice that most of the devices showing are in the DHCP range with the exception of Allens which is occasionally .2  and the printer at .4
Our comprehension will be best if you could confirm:
Which static addresses (i.e. manual entry) have you set up?
Which devices are supposed to be static?  
It appears that Allens is static as .2 is outside the DHCP range which (I think still) starts at .5.
And, at .4, the printer must be one of the static ones / manually entered, right?
Everything else appears to be dynamic / via DHCP as the addresses are .5 or higher.

My objective here is to conclusively separate the static-addressed devices from the dynamic-addressed devices.  Then, if this doesn't reveal an AHA!!, we would likely be looking at the dynamic range.

Forgive me if I'm being a bit pedantic but that's often the cure for these things.  
Are there any devices on the network that might be doing DHCP?  e.g. a wireless router or access point?

Regarding the printer:
I think that some printers with wireless have a mode that makes them a wireless access point.  So, if you don't have a "network" at all then the printer becomes the focal point and computers can hook up to it.  That means the printer will be a DHCP server.  So, you would very much want to make sure that this is NOT the mode the printer is in.  
I don't know about the Lexmark because I don't have your model number.....
But, HP printers with wireless will turn off the wireless if you plug in the ethernet.
So, something like that might be easy to try - but iffy without looking at the manual.
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Author Comment

by:CAR141
Comment Utility
I got another IP conflict message when I logged into my computer (windows 7) this morning. Checking the other computers Didn't show anything else with the same IP address. One computer was 2.9, another 2.5 and the iMac was 2.53, and the printer 2.4

The printer is set up as a static address: 192.168.2.4 - I checked with Lexmark.
The Printer says DHCP is off.

I haven't set up any other Static addresses for anything.

The ip pool starting address is 192.168.2.50
The ip pool ending address is 192.168.2.100

I did turn of ipv6
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Expert Comment

by:ltsweb
Comment Utility
Ok, that is great that it was on the Win 7 machine.

A few other questions, what are the names of the other machines for 2.9 and 2.5?  Do any of them have the same computer name?  For windows, you would go to cmd prompt (Start-Run-> CMD [enter]  then type hostname

Next, what was IP address of the machine with the ip conflict?? Was it static or dhcp?

Also, were you able to surf the web on the machine that had the IP conflict?  Or did you have to reboot?  

Don't forget, when you get the conflict, go into the Belkin router and dump the dhcp table so we can see what you see.

Finally, if you can, go to the Event Viewer (Rt click my computer, select manage, go to event viewer.  Do you see any error about the ip conflict?  I am looking for the ip conflict error message and under data to see if it gives you a mac address (as in machine address).
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Author Comment

by:CAR141
Comment Utility
names are allens and allen-6653398e4 for the win 7 and xp machines. Don't know the iMac name but know it isn't anything similar since it is my wife's and she bought it and set it up with the help of the apple store.

Machine with IP conflict was address 2.5.  DHCP not static

I could surf the web without rebooting. Couldn't fine any ip address conflict message on anything else.

I looked at the DHCP table this morning when I got that message. It didn't show anything at all - just headings but no machines.

If I figure out the event viewer I'll post that.  If I keep getting this IP address thing maybe I will have to bite the bullet and run that ip angry scanner.
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by:ltsweb
Comment Utility
2.5 is outside of your dhcp range.  If that is your workstation ip, it should be a static ip.

Based on your posts above, all dhcp starts at .50
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Author Comment

by:CAR141
Comment Utility
Guess I still don't understand Dhcp ranges. The IP address was 2.50 not 2.5
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Author Comment

by:CAR141
Comment Utility
What I could collect on latest IP address conflict incident:

LAN > DHCP Client List
       This page shows you the IP address, Host Name and MAC address of each computer that is connected to your network. If the computer does not have a host name specified, then the Host Name field will be blank. Pressing "Refresh" will update the list.
 
IP Address      Host Name      MAC Address
192.168.2.54            00:26:B0:86:E8:CD
192.168.2.52      Allens-iphone      F0:CB:A1:64:D8:7F
192.168.2.50            00:26:B0:98:34:D9
192.168.2.53      Allens      38:60:77:A8:97:CC
              
Allens is the Win 7
Win XP 2.51
Printer 2.4

 Event Details
- <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
- <System>
<Provider Name="Tcpip" />
<EventID Qualifiers="49152">4199</EventID>
<Level>2</Level>
<Task>0</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2012-03-29T19:11:18.865811300Z" />
<EventRecordID>27307</EventRecordID>
<Channel>System</Channel>
<Computer>Allens</Computer>
<Security />
</System>
- <EventData>
<Data />
<Data>0.0.0.0</Data>
<Data>00-26-B0-98-34-D9</Data>
<Binary>0000000003002C0000000000671000C0020000000000000000000000000000000000000000000000</Binary>
</EventData>
</Event>

Event General
Log Name:      Microsoft-Windows-Dhcp-Client/Admin
Source:        Microsoft-Windows-Dhcp-Client
Date:          3/29/2012 12:11:25 PM
Event ID:      1002
Task Category: Address Configuration State Event
Level:         Error
Keywords:      
User:          LOCAL SERVICE
Computer:      Allens
Description:
The IP address lease 192.168.2.50 for the Network Card with network address 0x386077A897CC has been denied by the DHCP server 192.168.2.1 (The DHCP Server sent a DHCPNACK message).
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Dhcp-Client" Guid="{15A7A4F8-0072-4EAB-ABAD-F98A4D666AED}" />
    <EventID>1002</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>3</Task>
    <Opcode>76</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2012-03-29T19:11:25.152622300Z" />
    <EventRecordID>1956</EventRecordID>
    <Correlation />
    <Execution ProcessID="512" ThreadID="4108" />
    <Channel>Microsoft-Windows-Dhcp-Client/Admin</Channel>
    <Computer>Allens</Computer>
    <Security UserID="S-1-5-19" />
  </System>
  <EventData>
    <Data Name="Address1">839035072</Data>
    <Data Name="HWLength">6</Data>
    <Data Name="HWAddress">386077A897CC</Data>
    <Data Name="Address2">16951488</Data>
  </EventData>
</Event>
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Expert Comment

by:ltsweb
Comment Utility
Ok, it looks like the device oo.26......d9 caused the conflict.  What is this device?  In the original dhcp table it doesn't show up.  I see the iPhones, the iMacs, but NOT these devices.

Do you have an unsecured wireless network?  Could these be neighbors??  There are two Mac addresses in the last table that you did not show us before.

You can see the device    00:26:B0:98:34:D9 we're also in earlier tables with no host name.

I did a Mac address lookup and it says the hw vendor is Apple.


Find that device!
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Author Comment

by:CAR141
Comment Utility
The 00.26...d9 is an iphone. so is the other device shown with no host name. We also have Nook and Kindles but their name is listed with the MAc address when they are connected.

The network is unsecured but our nearest neighbor is about 300 yards away. Also, we have rather severe bandwidth usage restrictions so I watch that pretty close. I don't think anyone but us is using our network.
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Accepted Solution

by:
ltsweb earned 500 total points
Comment Utility
Ok, at this point I think we have discovered what is causing the IP conflict.  When the mobile devices such as iphone or tablets receive an IP address they are held for a period of time.  If the device goes into standby, the ip is held and not released.  However, the Belkin may think it is available and then attempts to hand it out to one of your more permanent devices.  This causes a temporary conflict and the PC will attempt to get a new IP.  By way of the log file and follow up post of the dhcp table, the PC in fact renews and receives a new IP. (Yesterday, the PC went from .50 to .53) b/c the iphone claimed .50.

So, to solve the question you first posted, and to summarize these 45+ posts, it is my renewed suggestion to:

1) configure static Ip addresses for all permanent devices such as the computers and printers in the area outside of the dhcp scope (ex. 192.168.2.5, 2.6, 2.7, etc).

2) set the dhcp range to 192.168.2.50 through 2.100 (you already did this, skip this step)

3) Secure your wireless (you said the 00...d9 is your iphone; however, in an earlier dump of the dhcp table your iphone was  listed as F0...7F (see below):
 
192.168.2.2      Allens      38:60:77:A8:97:CC
192.168.2.7      Janets-iMac      3C:07:54:0C:8B:30
192.168.2.6      Janets-iMac      E4:CE:8F:65:3B:8E
192.168.2.9      Allens-iphone      F0:CB:A1:64:D8:7F  ******

Since MAC addresses do not change, I am not sure that you are correct that another iphone or device is not on your network.  You must have another iphone or ipad or apple device connected.

I believe this is going to be your best solution.  It is clear one of your devices is holding onto an ip address past its lease or the router is reset and cleared out all leases, but one of the devices did not release.

This is quite common if that device receives its dhcp from another server or router and thinks it owns the ip address for longer than it does!


Regards!!
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Author Closing Comment

by:CAR141
Comment Utility
OK. The unknown device  F0:CB:A1:64:D8:7F  is an old iphone. It isn't used as a phone anymore but is used as an ipod storing recorded books. (The new iphone no longer supports the type of files used by many audiobooks - or so I'm told. Anyway, I know it doesn't work for books.)

Thanks for your help on this. Sorry this has taken so many messages.
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