telnet-probe allows the pmdashping(1) daemons to establish connections to arbitrary local and remote
service-providing daemons so that response time and service availability information can be obtained.
The required host and port number arguments have the same meaning as their telnet(1) equivalents.
The -c option causes telnet-probe to perform a connect(2) only. This skips the read(2) and write(2)
exercise that would otherwise be done after connecting (see below).
Once the telnet connection has been established, telnet-probe reads from stdin until end-of-file, and
writes all the input data to the telnet connection. Next, telnet-probe will read from the telnet
connection until end-of-file, discarding whatever data it receives. Then telnet-probe exits.
To operate successfully, the input passed via telnet-probe to the remote service must be sufficient to
cause the remote service to close the connection when the last line of input has been processed, e.g.
ending with ``quit'' when probing SMTP on port 25.
By default telnet-probe will not produce any output, unless there is an error in which case a diagnostic
message can be displayed (in verbose mode only) and the exit status will be non-zero indicating a
failure.