tcpclient - creates an outgoing TCP connection.
tcpclient [
opts ]
host port prog
opts is a series of getopt-style options.
host is one argument.
port is one argument.
prog consists of one or more arguments.
tcpclient attempts to connect to a TCP server. If it is successful, it
runs
prog, with descriptor 6 reading from the network and descriptor 7
writing to the network. It also sets up several environment variables (see
tcp-environ(5) ).
The server's address is given by
host and
port.
port may be
a name from /etc/services or a number.
host may be 0, referring to the
local machine, or a dotted-decimal IP address, or a host name; it is fed
through qualification using dns_ip4_qualify.
If the server has several IP addresses,
tcpclient tries each address in
turn.
General options:
- -q
- Quiet. Do not print error messages.
- -Q
- (Default.) Print error messages.
- -v
- Verbose. Print error messages and status messages.
Connection options:
- -T x+y
- Give up on the connection attempt after x+y
seconds. Default: 2+58. When a host has several IP addresses,
tcpclient tries to connect to the first IP address, waits x
seconds, tries to connect to the second IP address, waits x
seconds, etc.; then it retries each address that timed out, waiting
y seconds per address. You may omit +y to skip the second
try. Before version 0.88, will use only x
(default: 60).
- -i localip
- Use localip as the IP address for the local side of
the connection; quit if localip is not available. Normally
tcpclient lets the operating system choose an address.
- -p localport
- Use localport as the TCP port for the local side of
the connection; quit if localport is not available. Normally
tcpclient lets the operating system choose a port.
- -d
- Delay sending data for a fraction of a second whenever the
remote host is responding slowly. This is currently the default, but it
may not be in the future; if you want it, set it explicitly.
- -D
- Never delay sending data; enable TCP_NODELAY.
Data-gathering options:
- -h
- (Default.) Look up the remote host name in DNS to set the
environment variable $TCPREMOTEHOST.
- -H
- Do not look up the remote host name in DNS; remove the
environment variable $TCPREMOTEHOST.
- -l localname
- Do not look up the local host name in DNS; use
localname for the environment variable $TCPLOCALHOST. A common
choice for localname is 0.
- -r
- (Default.) Attempt to obtain $TCPREMOTEINFO from the remote
host.
- -R
- Do not attempt to obtain $TCPREMOTEINFO from the remote
host.
- -t n
- Give up on the $TCPREMOTEINFO connection attempt after
n seconds. Default: 26.
tcpserver(1),
tcprules(1),
tcprulescheck(1),
argv0(1),
fixcrio(1),
recordio(1),
rblsmtpd(1), who@(1), date@(1), finger@(1), http@(1),
tcpcat(1),
mconnect(1),
tcp-environ(5)
http://cr.yp.to/ucspi-tcp.html