DHCP exclusions

PhilippeB

Is there a simple way to configure DHCP exclusions? We want to use a DHCP range from 192.168.124.0 ~ 192.168.127.253 with the following exceptions:
- 192.168.124.0 ~ 192.168.124.99
- 192.168.125.0 ~ 192.168.125.99
- 192.168.126.0 ~ 192.168.126.99
- 192.168.127.0 ~ 192.168.127.99

The goal is that every IP address given by the DHCP server has three digits on the last octet. Therefore, any address given by the DHCP server should be in one of these ranges:
192.168.124.100 ~ 192.168.124.255
192.168.125.100 ~ 192.168.125.255
192.168.126.100 ~ 192.168.126.255
192.168.127.100 ~ 192.168.127.253

This is the IP settings that we use:

Best regards, Philippe

PeterUK

No way to do this you would need to use a 3rd party DHCP server

or you can setup VLAN's to a switch

PhilippeB

@PeterUK , thanks for your confirmation. We thought that there isn't a simple way.

We probably solve it with a workaround and we'll define placeholders in the static DHCP table like this:

StefanZ

Why don't you just start your DHCP pools at .100?

You can still use static IPs with other clients like permanent infrastructure.

I do this – the Router is .1, the switches are .2 – .10, WiFi-APs .11 – .20, etc., PC clients start at .100.

Also: How is a IPv4 /24 Pool Size of 1023 possible? :-D

PhilippeB

https://community.zyxel.com/en/discussion/comment/62730#Comment_62730

The answer to the last question probably solves the mystery. As you can see in the screenshot, it's a /21 network. That's why the GUI allows a pool size of 1023 addresses. My customer doesn't nee more than 500 DHCP addresses, but would like to have all of them with three digits on the fourth octet (just for cosmetic reasons only),