Curl to establish TCP connections

I've been messing with curl to try to prove out my TLS configuration and I notice when I send the command, it established a TCP connection and then curl hangs.  The TCP connection doesn't get torn down, unless I kill the curl command.  This seems problematic to me.  What is to stop someone from scripting something to quickly eat up the TCP connections available on the SBC?  I have keep alive enabled on that interface, but it does not seem to kick in to tear down the connection.