tcp-environ - TCP-related environment variables
The following environment variables describe a TCP connection. They are set up by tcpclient and tcpserver as well as sslclient and sslserver.
Note that
TCPLOCALHOST, TCP6LOCALHOST,
TCPREMOTEHOST, TCP6REMOTEHOST, and
TCPREMOTEINFO, TCP6REMOTEINFO, can contain
arbitrary characters.
PROTO
The string TCP, or TCP6.
TCPLOCALHOST/TCP6LOCALHOST
The domain name of the local host, with uppercase letters converted to lowercase. If there is no currently available domain name for the local IP address, TCPLOCALHOST, TCP6LOCALHOST is not set.
TCPLOCALIP
The IPv4 address of the local host, in dotted-decimal form.
TCP6LOCALIP
The compactified IPv6 address of the local host.
TCPLOCALPORT/TCP6LOCALPORT
The local TCP port number, in decimal.
TCPREMOTEHOST/TCP6RMOTEHOST
The domain name of the remote host, with uppercase letters converted to lowercase. If there is no currently available domain name for the remote IP address, TCPREMOTEHOST or TCP6REMOTEHOST is not set.
TCPREMOTEINFO/TCP6REMOTEINFO
A connection-specific string, perhaps a username, supplied by the remote host via 931/1413/IDENT/TAP. If the remote host did not supply connection information, TCPREMOTEINFO, TCP6REMOTEINFO is not set.
TCPREMOTEIP
The IPv4 address of the remote host.
TCP6REMOTEIP
The IPv6 address of the remote host.
TCPREMOTEPORT/TCP6REMOTEPORT
The remote TCP port number.
TCP6INTERFACE
contains the interface name for IPv6 connections.
tcpclient(1), tcpserver(1), sslclient(1), sslserver(1), tcp(4)