Question Linksys router assigns IP addresses outside range

[Chrisser]

We use a Linksys router (WRT 1900 ACS) for internet access in a hut with different visitors throughout the season.

Mostly, devices are assigned IP addresses properly, but we've now had two instances that we know of where PCs (both Windows 10) have acquired IP addresses outside the range specified in the router's local network settings.

One PC acquired the IP 169.254.59.54

When typing "ipconfig /all" in the command prompt, the IP address is written as "169.254.59.54 (Preferred)".

The only way around the issue (that we've found) is to manually assign a 192.168.1.* IP address and a DNS server.

- Is there a way for the router to overwrite these "preferred" IPs and assign one within range that can connect to the internet?

Background:
The router's IP range is 192.168.100 to 192.168.1.249 and the maximum number of users is set to 150. The lease time is set to 1440 minutes (24 hours).

Here's a screenshot of the manual IP configuration that connected the PC to the internet:

(http://kulsvierhytten.dk/screenshots/Screenshot 2019-07-22 11.49.42.png)

Here's a screenshot of the automatic IP configuration when I don't manually select an IP:

(http://kulsvierhytten.dk/screenshots/Screenshot 2019-07-22 11.50.49.png)

 

[Lutfij]

I'd first start by looking at the Router's support page and see if there are any firmware updates pending.

 

[AllanGH]

What is the chance that these two computers are deceiving DHCP leases from a router that is not under your control?

Are there other sources of WiFi signals close to you?

 

[kanewolf]

The router isn't "assigning" that 169.254 IP address. The OS is defaulting to that address when no DHCP address is provided. That is an automatice private IP address -- https://www.webopedia.com/TERM/A/APIPA.html

You have a DHCP problem somewhere. Either you have run out of address space or something.

 

[jsmithepa]

^Default is right.

Either these 2 PC are borderline out of range, or your DHCP has run out of addresses, you should lower the lease interval to say 1 hour to age out disconnected clients faster.

 

[AllanGH]

That is an automatice private IP address

A windows "feature" that I wasn't aware of....

Thanks for providing me with something to learn today.

 

[digitalgriffin]

We use a Linksys router (WRT 1900 ACS) for internet access in a hut with different visitors throughout the season.

Mostly, devices are assigned IP addresses properly, but we've now had two instances that we know of where PCs (both Windows 10) have acquired IP addresses outside the range specified in the router's local network settings.

One PC acquired the IP 169.254.59.54

When typing "ipconfig /all" in the command prompt, the IP address is written as "169.254.59.54 (Preferred)".

The only way around the issue (that we've found) is to manually assign a 192.168.1.* IP address and a DNS server.

- Is there a way for the router to overwrite these "preferred" IPs and assign one within range that can connect to the internet?

Background:
The router's IP range is 192.168.100 to 192.168.1.249 and the maximum number of users is set to 150. The lease time is set to 1440 minutes (24 hours).

Here's a screenshot of the manual IP configuration that connected the PC to the internet:

(http://kulsvierhytten.dk/screenshots/Screenshot 2019-07-22 11.49.42.png)

Here's a screenshot of the automatic IP configuration when I don't manually select an IP:

(http://kulsvierhytten.dk/screenshots/Screenshot 2019-07-22 11.50.49.png)

What do you expect? If the user doesn't use DHCP to assign an IP address, then they are saying, "I know what I want my IP address to be" and it ignores your routers settings.

Unfortunately this means they likely won't have internet

This 169.x.x.x appears to be a private IP for a local network only. This means it's not exposed to the outside world. It maybe of their home network or work for protection reasons.

To be honest I won't connect to any unencrypted connection from here on out unless I have a VPN running.

 

[Chrisser]

Thank you for all the responses!

I tried resetting the router, reinstalling the firmware (since it was up to date) and lowering the lease time to two hours, but I'm still not getting a proper automatic IP address on the PCs.

I also tried selecting channels manually (which had no effect) - and it's in the middle of nowhere so there's no chance of overlap with other WiFi signals.

I agree that it seems like a DHCP issue with assigning IP adresses, but I have no idea how to solve that besides manually changing IPs and DNS settings on each computer (which isn't really practicable when we have to tell guests that).

- Any ideas?

 

[bill001g]

So I would do some careful testing. I would reset the router to factory and only setup the password and the wifi ssid/password stuff.

Now connect only 1 pc via ethernet and see if gets a IP. Next take a pc and connect via wifi. It is highly unlikely that you run out of ip addresses. It could in theory if some device is asking for 100s of them but I doubt you have 100 actual devices on your network.

If none of this works it almost has to be a defective router...even though I have never seen one fail like that. You can if you want load wireshark to your pc. What you should see is your PC send DHCP requests. This is a broadcast message that says someone give me a IP here is my mac address. Normally you get a offer message back from the router and it then sends a few more messages to accept it. In your case if the router is actually not sending out DHCP you will just see your pc constantly send broadcast and get no response. It eventually gives up and assigns the dummy 169.x.x.x ip address.