PONG

The PONG command is used as a response to a PING command, confirming an active connection.

Ping Response
Usage: PONG <server> [<server2>]
<server> The server that was pinged.
<server2> An optional second server, used when responding to a ping between two servers.

The PONG command is sent by a server or client in response to a PING command, indicating that the connection is still active and responsive. The server arguments must match those of the corresponding PING command.

(See section 4.6.3 of RFC 1459, 3.7.3 of RFC 2812)