Re: keepalive in socket server program

1 - How do I detect that a keepalive was sent

2 - What (if anything) do I need to send back.

It is generally good practice for servers to drop client connections after
periods of inactivity. But is sounds like your client wants the server to
support a "keepalive" request to override a default drop due to inactivity.

Don't think of "keepalive" as any "standard" character or string to look
for in the input buffer. Since you're writing a custom server, just
negotiate some protocol between you and your client to enable the client to
"override" the default inactivity timeout.