tcpclient(1)tcpclient(1)NAMEtcpclient - create an outgoing TCP connection
SYNOPSIStcpclient [ -46hHrRdDqQv ] [ -ilocalip ] [ -plocalport ] [ -Ttimeout‐
conn ] [ -llocalname ] [ -ttimeoutinfo ] [ -Iinterface ] host port pro‐
gram [ arg ... ]
DESCRIPTIONtcpclient 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, refer‐
ring to the local machine, or a dotted-decimal IP address, or a host
name; if a host has several IP addresses, tcpclient tries each 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-ilocalip
Use localip as the IP address for the local side of the connec‐
tion; quit if localip is not available.
-plocalport
Use localport as the port number for the local side of the con‐
nection; quit if localport is not available.
-Iinterface
Use interface 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 when‐
ever the remote host is responding slowly, to make better use of
the network.
-D Never delay sending data; enable TCP_NODELAY. This is appropri‐
ate 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 TCPLOCAL‐
HOST.
-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 time‐
outinfo seconds. Default: 26.
-4 Fall back to IPv4 sockets. This is necessary for terminally
broken systems like OpenBSD which will not let IPv6 sockets con‐
nect to V4-mapped IPv6 addresses. Please note that this also
applies to DNS lookups, so you will have to use an DNS resolver
with an IPv6 address to connect to IPv6 systems. Use DNSCACHEIP
to set the DNS resolver IP dynamically.
-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.
SEE ALSO
date@(1), finger@(1), http@(1), mconnect(1), tcpcat(1), tcpserver(1),
who@(1), tcp-environ(5)tcpclient(1)
