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John Threepwood
Asked: 2012-08-11 11:48:05 +0800 CST

What does the asterisk in the netstat output mean?

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# netstat -at
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 localhost:30037         *:*                     LISTEN
tcp        0      0 localhost:ipp           *:*                     LISTEN
tcp        0      0 *:smtp                  *:*                     LISTEN
tcp6       0      0 localhost:ipp           [::]:*                  LISTEN

What does the asterisk * in *:smtp mean ?

Why is there no IP address shown?

networking

1 Answers

  1. Best Answer

    It is a wildcard meaning "any".

    For example, in the third line:

    tcp        0      0 *:smtp                  *:*                     LISTEN

    The first *, in *:smtp, means the process is listening on all of the IP addresses the machine has. The second *, in *:*, means connections can come from any IP address. The third *, in *:*, means the connection can originate from any port on the remote machine.

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