getaddrinfo - Man Page

getaddrinfo [options...] host service

This tool provides a convenient command-line wrapper around the getaddrinfo(3) resolver function. It will perform a single lookup and print the returned results in a human-readable form. This is mainly useful when debugging address resolution problems, because it allows inspection of the getaddrinfo(3) behaviour itself, outside of any real program that is trying to use it.

--host,  -H HOST

Hostname to resolve. If not supplied, will use the first positional argument

--service,  -S SERVICE

Service name or port number to resolve. If not supplied, will use the second positional argument.

-4

Restrict to just AF_INET (IPv4) results

-6

Restrict to just AF_INET6 (IPv6) results

--stream

Restrict to just SOCK_STREAM results

--dgram

Restrict to just SOCK_DGRAM results

--proto PROTO

Restrict to just results of the given IP protocol

--passive

Set the AI_PASSIVE hint; results will used to bind() and listen() rather than connect()

--canonical

Retrive the canonical name for the requested host

--help

Display a help summary and exit

Each line of output will be given in a form that indicates the four result fields of ai_family, ai_socktype, ai_protocol and ai_addr. The first three are printed in the form of a socket(2) call, either symbolically or numerically, and the latter is printed as a plain string following it. For example

 socket(AF_INET , SOCK_STREAM, IPPROTO_TCP) + '127.0.0.1:80'

Paul Evans <leonerd@leonerd.org.uk>