habilitar el Forwanding
Habilitar el forwarding en el kernel, editando el archivo /etc/sysctl.conf

# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.ip_forward=1

# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1

Router add
route -p add 192.168.100.0 mask 255.255.255.0 192.168.1.254 METRIC 1
route add -net 192.168.100.0 netmask 255.255.255.0 gw  192.168.1.254
192.168.100.0 – ip a la que queremos acceder
192.168.1.254 – gateway de nuestro pc
192.168.1.1 . ip del pc al que queremos acceder