- A router is software running on hardware; any computer can be configured as a router.
- This guide shows how to obtain static IPv4 and IPv6 addresses using an L2TP tunnel from Andrews & Arnold Ltd (A&A), bypassing ISP restrictions like CGNAT.
- Set up a Debian/BSD machine with two Ethernet interfaces: one for WAN (connected to ISP) and one for LAN (hosting public subnet).
- Configure PPP over L2TP using xl2tpd and pppd, with static routes that force all traffic through the tunnel except for the A&A L2TP server.
- Enable packet forwarding, set up ifup/down scripts to add default routes, and use crontab or a loop to maintain the L2TP connection.
- No NAT or DHCP is used; hosts plug directly into the public network, requiring careful security considerations.
- The guide also covers DNS, MTU issues, reverse DNS (PTR records), and advises against running insecure devices on the network.