Dnsmasq and the network "pushing" on CentOS

This simple post shows you how tu push networks to your clients using the Dnsmasq DHCP server.

A possible scenario would be, your DHCP server (192.168.0.1) gives you 192.168.0.x address but you also need to reach 172.16.x.x and 10.0.x x networks, for access to (for instance) some VPN resources in your LAN. Those networks are NOT handled by your DHCP server. The quick solution is to make your DHCP server "pushing" that networks. And that is possibile thanks to "121" dhcp-option.

Let's assume our network id may be "vicinet" (you can also miss the network id, of course):

dhcp-option = vicinet, 121, 10.0.0.0/16, 192.16.0.1, 172.16.0.0/16, 192.168.0.1

The format will always be:

dhcp-option = 'id_net', 121, NETWORK, GATEWAY