IP address randomly changing

Discussion in 'Other Linksys Equipment' started by phoenixwtc, May 25, 2006.

  1. phoenixwtc

    phoenixwtc LI Guru Member

    I am new to this forum and not overly savvy when it comes to networking, so please bear with me a bit.

    I have a combination wired and wireless network running in my house. My internet modem is connected to a WRT54G v3 router with the latest firmware installed. From the router, I have a wired connection to a hub. From the hub, I have a wired connection to a computer running windows XP home and a Tivo. In adition to the two wired devices, I have two computers connected to the network connected on the wireless. Both computers are running windows XP - one the Home version and one the Professional version.

    The machines are set up for automatic IP address. The router has an IP address of As a result, the computers and the Tivo have addresses of 192.168.1.xxx. My problem is that at what appears to be random times, one or more of the computers will see a change from to When this happens, the computer will not find the internet connection through the router.

    To solve this problem, it seeems that I have to reset the router and reconfigure it using a wired connection from each computer to the router. What is frustrating is that it seems to be happening quite frequently - like once a day or more.

    It doesn't seem to be just the wired computer or the wireless one that is having this problem. Yesterday it was one that is connected through the wired network and this morning it was one connected on the wireless side.

    Any thoughts would be greatly appreciated.


  2. sufrano63

    sufrano63 Network Guru Member

    Are you saying that your ROUTER IP address randomly changed from to If yes, I would find out who else has access to your router; otherwise, there might be a security issue in your network
  3. phoenixwtc

    phoenixwtc LI Guru Member

    To be clear, when I go to the network connections window in Windows XP and right click on the network link for either the local area network or the wireless network (depending on which one is not working at the time), and then click on the support tab, the default gateway has changed from to

    WHo or how would someone else have access to my router to make such a change and what would this get them if they did? I am using the WEP security. Are you suggesting that someone can get into my router and change the IP address even when there is security on the router? How would this be happening? WHat can I do to prevent it if this is the case?

  4. sufrano63

    sufrano63 Network Guru Member

    The 3rd octet is your subnet, which would put you into a diff. network. I've never seen that happen unless someone change it manually.

    WEP is the worst security you can use and its hackable. If you can upgrade your firmware to see if it support WPA2 or at least WPA use it. Can you still verify your router is using the address? otherwise, your router has been hacked.
  5. phoenixwtc

    phoenixwtc LI Guru Member

    I have upgraded the firmware for the router. As far as the router IP address, if one computer shows, I can typically go to another computer and check and verify that the router is still on and is functioning properly.

    This happened this morning to me. One of the computers on the wireless was showing the The computer on the wired system that still went through the router was functioning properly and on

    In this case, I connected the wireless computer to the router via wire and was able to get on the internet that way. I went to the command prompt performed an ipconfig /release and then an IP config /renew and checked again and found the wireless was backon I disconnected the wire and went back on the wireless and it was fine.

    Yesterday morning it was one of the computers on the wired system that had switched to and after I disabled and enabled the network on the computer it was fine again.

  6. sufrano63

    sufrano63 Network Guru Member

    Only the GW was changed?
  7. phoenixwtc

    phoenixwtc LI Guru Member

    Sorry, but what does GW mean?
  8. sufrano63

    sufrano63 Network Guru Member

  9. phoenixwtc

    phoenixwtc LI Guru Member

    Okay, you are stretching my very limited knowledge base here. I updated the firmware for the router which I would suspect means that I updated the firmware for the gateway. I was unaware of any other firmware that might need to be updated. My router is a WRT54G ver 3 and the firmware upgrade took it up to a 4.0xx. I am not at home right now so I can't tell you exactly.

  10. sufrano63

    sufrano63 Network Guru Member

    Assuming you're using the stock Linksys firmware. URL below will direct you to correctly download the latest firmware for your router. Confirming you have an older version before upgrading

  11. phoenixwtc

    phoenixwtc LI Guru Member

    That was the site that I downloaded the upgrade from. The most current version is 4.20.7 which is what my router is now running. I installed this firmware last weekend and the problem has persisted since that point.

  12. howardp6

    howardp6 Network Guru Member

    If you had not done so, reset the router to factory defaults and see if clears the problem. Then re-enter your setting. You should always reset the router to factory defauts before after a firmware upgrade. Upgrades should only be done from a wired connection.
  13. phoenixwtc

    phoenixwtc LI Guru Member

    The upgrade was done per the directions that I received from the Linksys tech support which included resetting to factory defaults and then upgrading the firmware. The problem with the router changing from to existed prior to the upgrade and since the upgrade.

    From what I can tell, this is not a problem that others have seen before. WHen I have asked linksys techs they didn't understand it either. I've had them on the phone going through step by step the fix and when we are finished, everything works fine for a short period of time. Then out of the blue one day the settings will change on one computer and I have to go through hoops to get it working again.

    It is very frustrating and answers don't seem to be easy to come up with. I've talked it over with our IT network pros in the office, with linksys, and I was hoping that you guys on this forum would have some idea as to what might be happening here.

  14. howardp6

    howardp6 Network Guru Member

    The subnet that the DHCP server issues is not suppose to change. There may be a problem with the router. Try to get Linksys to issue a RMA and return the router to them if its is still under warantee.
  15. Toxic

    Toxic Administrator Staff Member

    This is a very starnge occurance that i have never heard of. when your IP address/gateway changes, can you ping the gateway/router at all without you trying to get it all back to normal?

    I am wanting to see if the actual router does change IP addresses or you have so strange virus/trojan than it playing tricks on your systems

    when you reset the router you do press the reset for 30 seconds yes?

    one other thing you could do it test this router at another location. just to see if it is the router or something unknown on the LAN
  16. sufrano63

    sufrano63 Network Guru Member

    - Does the gw changed on 1 or multiple PCs randomly?
    - Try scanning for spyware or malware.
    - Any other network settings changed besides the gw address?
  17. RonWessels

    RonWessels Network Guru Member

    Is it possible that one of your PC's was formerly serving as the internet gateway for your home network and you have left "Internet Connection Sharing" turned on?

    That sure acts like there's a second DHCP server running somewhere.
  18. phoenixwtc

    phoenixwtc LI Guru Member

    The change is only to the IP for the gateway and the IP for the specific computer. FOr instance, if the router changes to, then the IP address for the computer goes to 192.168.2.xxx. This typically only happens to one of the computers and not the others.

    As far as one of the computers being set up as the internet gateway in the past, the answer would be no. We had the network in place before we purchased these specific computers.

    One thought that I had after doing a bit more reading on the issue would be if one of our cordless phones might be interfering somehow. We have two cordless phones systems set up in the house. One system is a 5.8 Ghz system and the other one is 2.4 Ghz. If I am correct, the linksys router operates on 2.4 Ghz. Since the 2.4 Ghz phone is right next to one of the computers and just a few yards away from the router, could that be causing any problems?

    As a test, we have disabled the phone to see if the problem goes away. Still too early to know for sure, though.

  19. sufrano63

    sufrano63 Network Guru Member

    The only conflict between the 2.4Ghz phone and the router both using the same 2.4Ghz frequency is the signal. It woulnd't have caused it to change your network settings on your computer. Instead of trying to figure out this problem. If you could try exchange it for a new router and start over with a fresh settings and better security WPA or WPA2. I still think your internal wireless network is weak (due to using a WEP) and probably is hacked by someone.

    My .02 cent
  20. howardp6

    howardp6 Network Guru Member

    If the router goes to a different subnet, the other computers shoyld not be able to communicate with it.
  21. kg4mrv

    kg4mrv Network Guru Member

    Are there any other routers in the area. You may be losing connection to your router and connecting to the other. This could cause you to see the gateway change. This is just the wireless computers?
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