Установка 
cd /usr/ports/net/isc-dhcp42-server 

dhcpd_enable="YES"
dhcp_ifaces="em1"


''default-lease-time 600;\\
max-lease-time 7200;\\

ddns-update-style none;\\

log-facility local7; \\


subnet 10.10.10.0 netmask 255.255.255.0 { \\
  range 10.10.10.10 10.10.10.50;\\
  option routers 10.10.10.1, 10.10.10.2 ; \\
  option domain-name "mkm.local";\\
  option domain-name-servers 8.8.8.8; \\
}
''













добавим в /etc/rc.conf 

dhcpd_enable="YES"

dhcpd_ifaces="em1"

/usr/local/etc/rc.d/isc-dhcpd start