# 4in6

4in6 is a method to transmit [IPv4](/glossary/i/ipv4) traffic over explicit [IPv6](/glossary/i/ipv6) connections.

It is achieved by using tunneling to encapsulate IPv4 traffic over configured IPv6 tunnels as defined in [RFC 2473](/glossary/rfc/2473).

These tunnels are usually manually configured but they can be automated using protocols such as [TSP](/glossary/i/ipv6).