Introduction to TCP

The TCP Internet Protocol (TCP/IP), described in RFC793, is simple in concept, but the reality of making it work reliably in a wide range of conditions adds a lot more complexity. There are a large number of protocol counters that can be viewed with netstat -s, but only a small number of them are of general interest. There is a set of tunable values that can be obtained and set by means of the ndd command.

The netstat -s command lists several protocols, but here I just show the TCP data that is reported by Solaris 2.6.

 TCP tcpRtoAlgorithm = 4tcpRtoMin = 200 tcpRtoMax =240000tcpMaxConn = -1 tcpActiveOpens = 99968tcpPassiveOpens = 42383 tcpAttemptFails = 26522tcpEstabResets = 363 tcpCurrEstab = 78tcpOutSegs =14443181 tcpOutDataSegs ...

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