@helian

Hi,

Which Distribution do you use?
there is many solutions for this Problem.

Example:
1- you have to edit your dhcp-range

I do not use the fog server as DHCP-Server. But i can help u if u have Debian Distribution 😉

nano /etc/dhcp/dhcpd.conf

find the line like this:

subnet 192.168.14.0 netmask 255.255.255.0 { range 192.168.14.10 192.168.14.100; option routers 192.168.14.1; option domain-name-servers 8.8.8.8, 8.8.4.4; default-lease-time 600; max-lease-time 7200; }

you can setup the range of DHCP-Server as u want. I will prefer from 150-230. be careful just edit the last octet do not change the your whol network.

Restart ur DHCP Server

systemctl restart isc-dhcp-server

Now you can reserve the IP-Adresses in the file DHCP-Leases. In this file you will find every Host in this network. You can use Every IP-Address under 192.168.14.150. do not use the IP-Address of the FogServer or any IP-Address which is already in used.

Nano /var/lib/dhcpd/dhcpd.leases systemctl restart isc-dhcp-server

I hope that i could help 🙂