OpenWRT DHCP configuration

Bruno_A · December 6, 2019

Hello all,

I am running an OpenWRT router. My main lan, called "lan", has the IP of 10.230.0.1, however, when a device is connected to it, via ethernet, or wirelessly, the device is given a 10.0.0.x IP, instead of a 10.230.0.1. The devices can still connect to the internet, however, I'm not quite sure why this is happening, and if I can change it. The reason why I wanted to change it, is because I wanted 10.0.0.x for a guest network and I also want to understand why this is happening. This is happening after I reset my router and reconfigured it, today. Yesterday, I had the same LAN setup, and a guest WAN, that used 10.0.0.1 and every device connected wirelessly, either to the guest network, or not, would be given the 10.0.0.x address. Connecting certain devices to the Wi-Fi was a pain, as well, as quite often they wouldn't have internet access. Any ideas?

Catsrules · December 6, 2019

3 minutes ago, Bruno_A said:

Hello all,

I am running an OpenWRT router. My main lan, called "lan", has the IP of 10.230.0.1, however, when a device is connected to it, via ethernet, or wirelessly, the device is given a 10.0.0.x IP, instead of a 10.230.0.1. The devices can still connect to the internet, however, I'm not quite sure why this is happening, and if I can change it. The reason why I wanted to change it, is because I wanted 10.0.0.x for a guest network and I also want to understand why this is happening. This is happening after I reset my router and reconfigured it, today. Yesterday, I had the same LAN setup, and a guest WAN, that used 10.0.0.1 and every device connected wirelessly, either to the guest network, or not, would be given the 10.0.0.x address. Connecting certain devices to the Wi-Fi was a pain, as well, as quite often they wouldn't have internet access. Any ideas?

What is your subnet mask?

what is the DHCP range on the DHCP server?

Bruno_A · December 6, 2019

3 minutes ago, Catsrules said:

What is your subnet mask?

what is the DHCP range on the DHCP server?

My subnnet mask is 255.0.0.0. As for the DHCP range, I don't know, OpenWRT does not show that. In the DHCP settings, you can enable/disable the DHCP server and change a few more settings, but not the range, like most routers.

Catsrules · December 6, 2019

25 minutes ago, Bruno_A said:

My subnnet mask is 255.0.0.0. As for the DHCP range, I don't know, OpenWRT does not show that. In the DHCP settings, you can enable/disable the DHCP server and change a few more settings, but not the range, like most routers.

Ahh that is why your router IP is 10.230.0.1 and it can still talk to devices on 10.0.0.1 your subnet mask is huge. Your network is basically 10.x.x.x

I am using LEDE so it might be slightly different interface then OpenWRT, but the range settings are under the LAN interfaces, edit the interface you want DHCP on and at the bottom. It is kind of primitive but start is where you want DHCP pool to start and Limit is where your want the DHCP pool to end.

Personally I would change the router IP to 10.0.0.1 then I would change the subnet mask to 255.255.255.0, then set the DHCP range to be 100 to 100.

If you want the guest network totally separate, I would change it to be 10.1.0.1 with a subnet mask of 255.255.255.0. start it at 100 and go to 50 or something.

Bruno_A · December 6, 2019

1 hour ago, Catsrules said:

Ahh that is why your router IP is 10.230.0.1 and it can still talk to devices on 10.0.0.1 your subnet mask is huge. Your network is basically 10.x.x.x

I am using LEDE so it might be slightly different interface then OpenWRT, but the range settings are under the LAN interfaces, edit the interface you want DHCP on and at the bottom. It is kind of primitive but start is where you want DHCP pool to start and Limit is where your want the DHCP pool to end.

Personally I would change the router IP to 10.0.0.1 then I would change the subnet mask to 255.255.255.0, then set the DHCP range to be 100 to 100.

If you want the guest network totally separate, I would change it to be 10.1.0.1 with a subnet mask of 255.255.255.0. start it at 100 and go to 50 or something.

Awesome. I actually set up the guest network again. I have my LAN as 10.230.0.1 and my guest LAN as 10.230.1.1 and configured the firewall rules following a tutorial from OpenWRT.org. The subnet mask is now set to 255.255.255.0 for both LANs. Thanks for the help, OpenWRT is challenging my network knowledge and it's good to know I can count on people like you in this forum for help.