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TCPING(1) User Manuals TCPING(1)

NAME tcping - non-blocking TCP connection test

SYNOPSIS tcping [-q] [-f <4|6> ] [-t timeout-sec | -u timeout-usec ] host port

DESCRIPTION tcping attempts to complete a TCP connection to a host:port combination within the time interval timeout-[u]sec. The result of the operation is encoded as a return value.

OPTIONS -q Quiet flag. Suppress all informational output.

   -f <4|6>
          IP  protocol  family  to  use:  4 for IPv4, 6 for IPv6.  If left
          unspecifed, the implementation will use the protocol  family  of
          the first record returned from getaddrinfo(3), based on the for-
          mat of the host parameter.  Specifying  host  as  dotted-decimal
          IPv4 or hex IPv6 address string will use the respective protocol
          stack. Specification as a hostname character string will cause a
          dependency  on  the order of IPv4 and IPv6 records returned from
          getaddrinfo(3).

   -t timeout-sec
          Connection timeout in seconds.

   -u timeout-usec
          Connection timeout in microseconds.

   host   Destination host. Either a host name node name or a numeric host
          address  string  (i.e., a dotted-decimal IPv4 address or an IPv6
          hex address), per RFC 2553.

   port   Destination port. Either a service name or a decimal  port  num-
          ber, per RFC 2553.

RETURN VALUES tcping encodes the result of the connection attempt in its return value:

   0      The connection attempt was successful.

   1      The connection attempt was unsuccessful.

   2      The connection attempt timed out.

   255    An error occured.

DIAGNOSTICS Unless the quiet (-q) flag is set, the following diagnostics are issued on stderr. The messages align with the program return value (see above).

   <host> port <port> open.
          The connection attempt to host:port was successful.
   <host> port <port> closed.
          The connection attempt to host:port  was  unsuccessful  and  the
          server side signaled a closed port.
   <host> port <port> user timeout.
          The  connection attempt to host:port did not complete within the
          user-defined timeout interval.

AUTHOR Marc Kirchner

HISTORY tcping came to be in 2002 as a utility to allow basic TCP connection checking and to enable failure shortcircutry before issuing network commands with long timeouts (on Solarix 2.x, Solaris 7/8, AIX and Linux). IPv6 functionality was added for 2.0.0 in 2023, which also dropped support for the AIX and Solaris OS.

ACKNOWLEDGEMENTS Many thanks to Kai Hambrecht, John Smith and Vincent Loriot.

SEE ALSO nc(1)

Linux MARCH 2023 TCPING(1)