tcpclient(1)

NAME
tcpclient - create an outgoing TCP connection

SYNOPSIS
tcpclient [ -46hHrRdDqQv ] [ -ilocalip ] [ -plocalport ] [ -Ttimeoutconn ] [ -llocalname ] [ -ttimeoutinfo ] [ -Iifname ] host port program [ arg ... ]

DESCRIPTION
tcpclient attempts to connect to a TCP server. If it is successful, it runs program with the given arguments, with descriptor 6 reading from the network and descriptor 7 writing to the network. The server's address is given by host and port. host may be 0, which is identical to 127.0.0.1, or ::1 referring to the IPv6 loopback address, a compactified IPv6 address, a dotted-decimal IPv4 address, or a host name. If a host name is given, tcpclient facilitates a DNS lookup and tries each address in turn. port may be a numeric port number or a port name. tcpclient sets up several environment variables, as described in tcp-environ(5).

OPTIONS

-4  Fall back to IPv4 sockets.

-6  Force IPv6 mode in UCSPI environment variables, even for IPv4 connections. This will set PROTO to TCP6 and put IPv4-mapped IPv6 addresses in TCPLOCALIP and TCPREMOTEIP.

-ilocalip
    Use localip as the IP address for the local side of the connection; quit if localip is not available.

-plocalport
    Use localport as the port number for the local side of the connection; quit if localport is not available.

-Iifname
    Use ifname as the local network interface. This is only defined for IPv6 sockets and needed if you use link-local IPv6 addresses.

-Ttimeoutconn
    Give up on the connection attempt after timeoutconn seconds. Default: 60. This timeout applies to each IP address tried.

-d  (Default.) Delay sending data for a fraction of a second whenever the remote host is responding slowly, to make better use of the network.

-D  Never delay sending data; enable TCP_NODELAY. This is appropriate for interactive connections.

-q  Quiet. Do not print any messages.

-Q  (Default.) Print error messages.

-v  Verbose. Print all available messages.

DATA-GATHERING OPTIONS

-h  (Default.) Look up the remote host name for TCPREMOTEHOST.

-H  Do not look up the remote host name; unset TCPREMOTEHOST.

-llocalname
    Do not look up the local host name; use localname for TCPLOCALHOST.

-r  (Default.) Attempt to obtain TCPREMOTEINFO from the remote host.

-R  Do not attempt to obtain TCPREMOTEINFO from the remote host.

-ttimeoutinfo
    Give up on the TCPREMOTEINFO connection attempt after timeoutinfo seconds. Default: 26.

ENVIRONMENT VARIABLES READ
tcpclient reads the environment variable DNSCACHEIP which can be used to specify the recursive DNS Resolver dynamically.

SEE ALSO
date@(1), finger@(1), http@(1), mconnect(1), tcpcat(1), tcpserver(1), who@(1), tcp-environ(5)