Configuring TCP keepalive after accept

Question

After the accept() on a socket, I\'m trying to configure the TCP keepalive.

SockConnected = accept(SockListen, &RemoteAddr,
                   &         


        

Answer 1

SO_KEEPALIVE should be used with SOL_SOCKET, not IPPROTO_TCP or SOL_TCP. See socket(7) and tcp(7).

So try this:

int val = 1;
setsockopt(SockConnected, SOL_SOCKET, SO_KEEPALIVE, &val, sizeof(val));

I guess TCP_KEEPIDLE and similar options are just ignored if SO_KEEPALIVE was not set correctly, and SOL_TCP is a synonym for IPPROTO_TCP.

If it does not help, consider posting a minimal example that reproduces the problem.