Link to home
Start Free TrialLog in
Avatar of Tarkisal
Tarkisal

asked on

Wireless randomly handing out bad IP addresses

I recently took over support for an office that is running an old set of Cisco Aironet routers. This office has a good amount of wireless devices - at least 15-20 laptops and computers, along with Nest thermostats, carbon dioxide sensors, and more. What seems to happen is randomly a connected computer will suddenly lose it's connection. Where normally the connection will be 192.168.1.X (Their standard subnet) a computer will randomly drop and suddenly show a 192.168.0.X address, complete with 192.168.0 gateway and no internet access. After sometime the connection will re-establish.

Now I'm 99% sure this is simply the old Wi-Fi network unable to keep up with the number of wireless devices and it's dropping and re-acquiring leases. I just wanted to confirm that anyone else has seen this before. I was planning on replacing the Wi-Fi anyway, but it seems odd. In my experience, when a computer only has limited connectivity it would show something like a 169 address, or no address at all. The fact that it's suddenly coming up with a 192.168.0 address seems oddly specific.

Thanks for any input you might have.
Avatar of John
John
Flag of Canada image

Nest thermostats, carbon dioxide sensors, and more...

Try setting these devices with Static IP addresses in the non-DHCP address area of your router.

More practically, upgrade your router to a more modern N or N/AC wireless router.
Avatar of David Sankovsky
I Agree with John on this one, Generally, I'd only allow simple endpoint computers to run off DHCP everything else (iOT devices, server and etc.) Would run off Static IP Addresses (Don't forget to remove those addresses from the DHCP server pool).

As to your problem, if it also happens to computers as well as the iOT devices, there are several things to check.
As soon as a computer would obtain a different IP Address, run the ipconfig /all | find "DHCP Server" command to see which server allocated the address to the computer. (this step could be completely useless however if both Ranges are dealt by the same DHCP server)
Avatar of Tarkisal
Tarkisal

ASKER

Thank you for your comments. I replaced the existing wifi network with a brand new Unifi network that seems to be working well. And yet, the problem remains. Random computers will suddenly lose their standard 192.168.1.X address and replace it with 192.168.0.X with a different gateway and DNS server. I'm not sure how they're even getting this information.

I did notice all of the Nest devices appear to be pulling the 192.168.0.X address no matter what. I'm suspecting they are the root cause of this problem.

I think I will have to go through and set each laptop and Nest to a static IP, as you suggested. Now I just have to figure out how to change the IP on the Nest equipment.
ASKER CERTIFIED SOLUTION
Avatar of Blue Street Tech
Blue Street Tech
Flag of United States of America image

Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
All,

Thank you very much for your quick and helpful responses. I apologize, I didn't see the Find DHCP server message earlier. I did a search, as suggested, and it pointed me to 192.168.0.1. Connecting to that brings me to the Arris cable modem provided by Spectrum. I now believe this cable modem needs to be configured to not provide DHCP, which SHOULD fix the problem. I am working on getting this done now, and will update this ticket when I have my results.

Thanks
SOLUTION
Link to home
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial