Check TCP connectivity

TCP/IP, Transport protocol, UDP, SCTP, QUIC, subnet mask, Routing protocols: BGP, routing table, Policy based routing, multicast, TCP Fast Open, RDP, TTL, RTT, MPTCP, Large send offload (LSO): (TSO, GRO, GSO, TCP checksum), ethtool, SCTP, 5-Tuple, Check TCP connectivity, TCP window size, /proc/sys/net/ipv4/tcp_rmem, ack, List of TCP ports, localhost, broadcast address