Here we consider home user networks (staff, students) wanting connectivity, possibly behind a NAT, possibly with just a single machine, possibly with a dynamic IPv4 address.

The solutions available include

• Teredo
• Tunnel broker
• 6to4

Some tunnel broker implementations, especially with TSP, can support IPv4 NAT traversal and/or dynamic IPv4 addresses. As described above, 6to4 can have reliability issues dependent on the relay location (but is strong when used to connect just to other 6to4 sites, e.g. other home networks using it).Teredo is a method of ‘last resort’, designed for use behind IPv4 NATs. The broker or 6to4 would
generally be preferred to Teredo.