Solved

Strange IP Addresses being picked up

Posted on 2012-03-16
18
393 Views
Last Modified: 2012-03-31
The last few days , a number of our desktops have acquired strange IP addresses , outside our range . They pick up an address in the range 192.168.11.xx . To reset I have to go into CMD and ipconfig /release then ipconfig/renew . Is there any way this can be prevented ?
All help gratefully received .

regards ,
0
Comment
Question by:TomTierney
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 7
  • 5
  • 4
18 Comments
 
LVL 14

Expert Comment

by:John-Charles-Herzberg
ID: 37728832
Have you scanned you network for another DHCP server?

Thanks
JC
0
 
LVL 30

Assisted Solution

by:IanTh
IanTh earned 500 total points
ID: 37728853
when it has a 192.168.11.x in the ipconfig get the gateway ip address as thats the device that has the dhcp  server role for 192.168.11.x when you have the gateway that may show you whats going on

as 192.168.x.x is a home ip range I bet somebody has put their home router with dhcp running onto your lan imho
0
 

Author Comment

by:TomTierney
ID: 37728917
How can I fix it ??
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 14

Expert Comment

by:John-Charles-Herzberg
ID: 37728929
This software might help.

DhcpExplorer allows you to discover DHCP servers on your local subnet or LAN

http://www.softpedia.com/get/Network-Tools/Network-IP-Scanner/DHCPExplorer.shtml
0
 
LVL 14

Expert Comment

by:John-Charles-Herzberg
ID: 37728933
0
 
LVL 14

Expert Comment

by:John-Charles-Herzberg
ID: 37729523
This video might help if you are OK with using linix to help find the DHCP server(s)

3hacks : Rogue DHCP Server Detection (dhcp_probe)

http://www.youtube.com/watch?v=bc1m4Npoyik

Thanks
JC
0
 

Author Comment

by:TomTierney
ID: 37736984
Still got the problem . Downloaded DHcP explorer but that only shows our subnet . I viewed the video but didn't 'get it' . I can see no visible signs of a 'home' address so difficult to remove . I really am struggling with this one . Anyone ?
0
 
LVL 30

Expert Comment

by:IanTh
ID: 37737124
can yu ping the rogue ip addres I mean does it actually exist
0
 

Author Comment

by:TomTierney
ID: 37737395
I tried pinging one of the addresses I have seen and it just timed out .... 192.168.11.11
0
 

Author Comment

by:TomTierney
ID: 37737837
Our RAS server has an address of 192.168.11.14 ?? I don't recall this . Does this sound correct ?
0
 
LVL 30

Expert Comment

by:IanTh
ID: 37738198
whats your lan ip address range ? 10.0.0.x or someting
0
 

Author Comment

by:TomTierney
ID: 37738339
192.168.16.x
0
 

Accepted Solution

by:
TomTierney earned 0 total points
ID: 37747205
Hi , it appears that my problem was caused by a Buffalo router that we have deployed at one of our satellite sites . We spotted this on a tech forum and now , having disabled this equipment , normality has been restored .
Thanks for all the input .

regards ,
0
 

Author Comment

by:TomTierney
ID: 37747435
I've requested that this question be closed as follows:

Accepted answer: 0 points for TomTierney's comment #37747205

for the following reason:

It appears to have done the trick . It would appear to be a common occurrence .<br /><br />regards ,
0
 
LVL 30

Expert Comment

by:IanTh
ID: 37747436
I would like to point to my second post where I stated

as 192.168.x.x is a home ip range I bet somebody has put their home router with dhcp running onto your lan imho

and your cooment

Hi , it appears that my problem was caused by a Buffalo router that we have deployed at one of our satellite sites . We spotted this on a tech forum and now , having disabled this equipment , normality has been restored

how is that different I stated it was another router and your fix is another router
0
 
LVL 30

Expert Comment

by:IanTh
ID: 37790865
thanks
0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How to provide security from internet without NAT 7 62
Connecting two LAN's across the Internet 6 42
Getting started with Wget 7 64
Display home - no ADSL or internet 3 169
Preface There are many applications where some computing systems need have their system clocks running synchronized within a small margin and eventually need to be in sync with the global time. There are different solutions for this, i.e. the W3…
Configuring network clients can be a chore, especially if there are a large number of them or a lot of itinerant users.  DHCP dynamically manages this process, much to the relief of users and administrators alike!
With Secure Portal Encryption, the recipient is sent a link to their email address directing them to the email laundry delivery page. From there, the recipient will be required to enter a user name and password to enter the page. Once the recipient …
Are you ready to implement Active Directory best practices without reading 300+ pages? You're in luck. In this webinar hosted by Skyport Systems, you gain insight into Microsoft's latest comprehensive guide, with tips on the best and easiest way…

751 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question