The IRC server actually is what is supposed to send PING to clients which have no detected activity within a given interval. The client is supposed to respond

The IRC server actually is what is supposed to send PING to clients which have no detected activity within a given interval. The client is supposed to respond with PONG. This is straight out of RFC 1459[1]: The PING message is used to test the presence of an active client at the other end of the connection. A PING message is sent at regular intervals if no other activity detected coming from a connection. If a connection fails to respond to a PING command within a set amount of time, that connection is closed. [1] https://tools.ietf.org/html/rfc1459#section-4.6.2 https://tools.ietf.org/html/rfc1459#section-4.6.2 So it seems this client is simply sending data on a regular interval, but it is not sending correct data and will certainly not work on all servers or networks (such as networks with a smaller ping interval than 200 seconds). I may just be an old unix beard now, but I remember when reading the RFC was standard for your home-grown clients.