With the recent (forced) transition from ADSL to fibre optic broadband internet, an interesting oppertunity arose. It enabled assigning the public ip address from the provider easily to a network interface of my private home server. The fibre optic cable entering our house is fed to a media converer which has a UTP connection. The default set-up from the installer attaches the media converter directly to the supplied T-Mobile router. For home networking enthousiasts it is also possible to connect the media converter directly to your home server. But why is this cool?! Here are two reasons:

• Avoids the need to encapsulate IPsec traffic within UDP packets.
• You can finally make use of an IPv6 tunnel broker. (Shame on you T-mobile/Odido for not supporting IPv6 yet).

This brief guide will show you how this is done in FreeBSD. Without further ado, this is how it is done:

vlans_em2="tmob"
create_args_tmob="vlan 300"
ifconfig_em2="up"
ifconfig_tmob="SYNCDHCP"

For those wo did not realise it yet, these settings should be added to /etc/rc.conf.

The media converter is directly attached to the em2 network interface using a UTP cable. T-mobile uses a VLAN tag of 300 for their network. The SYNCDHCP option force the startup script to wait for the dhclient program to finish. A server with just one network interface would not be very useful in this situation, so I’ve added a second network interface to my server which will be connected to a switch and is for local traffic. In this case the server must take care of NAT, which whas previously done by the T-Mobile router. The relevant lines from the pf.conf file are:

ext_if="tmob"
nat on $ext_if from 192.168.0.0/24 to any -> ($ext_if)