This program package consists of 3 commands, yaegashi/takeshi/zephyr6. They were formerly known as server/connect/relay, however, which dealt with only IPv4 protocol.
Yaegashi, (or server), helps to create a simple server, and takeshi (or connect) to create a simple client, by executing a user process that inputs from stdin and outputs to stdout. Zephyr6 (or relay) waits a TCP connection and simply relay it to another host. They are built as one executable binary.
Yaegashi/Takeshi/Zephyr6 are small and simple tools and therefore they have little risk of security hole and improper operation.
YAEGASHI Takeshi, whose handle is Zephyr, is the original author of server/connect/relay. We call IPv6-aware versions of these tools "yaegashi/takeshi/zephyr6" in order to distinct themselves from the older versions and emphasize IPv6 awareness, with great respect.
Manual pages: Yaegashi/Takeshi/Zephyr6
Yaegashi/Takeshi/Zephyr6 (server/connect/relay) is distributed under the BSD-style license.