NetBSD/usr.bin/getaddrinfo/getaddrinfo.1

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.\" $NetBSD: getaddrinfo.1,v 1.2 2013/09/30 08:13:59 wiz Exp $
.\"
.\" Copyright (c) 2013 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This documentation is derived from text contributed to The NetBSD
.\" Foundation by Taylor R. Campbell.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.Dd September 30, 2013
.Dt GETADDRINFO 1
.Os
.Sh NAME
.Nm getaddrinfo
.Nd resolve names to socket addresses
.Sh SYNOPSIS
.Nm
.Op Fl cNnP
.Op Fl f Ar family
.Op Fl p Ar protocol
.Op Fl s Ar service
.Op Fl t Ar socktype
.Op Ar hostname
.Sh DESCRIPTION
The
.Nm
utility resolves host and service names to socket addresses as if with
the
.Xr getaddrinfo 3
routine and formats them to standard output.
.Pp
The output is a sequence of lines of space-separated fields:
.Dl socket-type address-family protocol [af-specific data ...]
.Pp
For the internet family, the address-family-specific data are the
internet address and the port number.
.Pp
Although the
.Nm
utility may query the DNS to give answers, depending on the
system's
.Xr nsswitch.conf 5
configuration, it is not intended to be a general-purpose utility to
query the DNS; use the
.Xr dig 1
utility for that.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl c
Look up a canonical name as if with the
.Dv AI_CANONNAME
flag to
.Xr getaddrinfo 3
and print it on the first line before the socket addresses.
.It Fl f Ar family
Specify an address family.
Address families are named like the
.Dv AF_...
constants for address family numbers in the
.Aq Pa sys/socket.h
header file but without the
.Dv AF_
prefix and lowercase.
For example,
.Dq inet
corresponds with
.Dv AF_INET .
.It Fl N
Treat the service as numeric and do not attempt service name
resolution, as if with the
.Dv AI_NUMERICSERV
flag to
.Xr getaddrinfo 3 .
.It Fl n
Treat the hostname as a numeric address and do not attempt name
resolution, as if with the
.Dv AI_NUMERICHOST
flag to
.Xr getaddrinfo 3 .
.It Fl P
Return socket addresses intended for use with
.Xr bind 2 ,
as if with the
.Dv AI_PASSIVE
flag to
.Xr getaddrinfo 3 .
By default, the socket addresses are intended for use with
.Xr connect 2 ,
.Xr sendto 2 ,
or
.Xr sendmsg 2 .
.It Fl p Ar protocol
Specify a protocol.
Protocols may be numeric, or symbolic as listed in
.Xr protocols 5 .
.It Fl s Ar service
Specify a service to look up.
If no service is specified, a hostname must be specified.
.It Fl t Ar socktype
Specify a socket type.
Socket types are named like the
.Dv SOCK_...
constants for socket type numbers in the
.Aq Pa sys/socket.h
header file but without the
.Dv SOCK_
prefix and lowercase.
For example,
.Dq dgram
corresponds with
.Dv SOCK_DGRAM .
.El
.Sh EXIT STATUS
.Ex -std getaddrinfo
.Sh EXAMPLES
Look up
.Dq www.NetBSD.org :
.Bd -literal -offset indent
$ getaddrinfo www.NetBSD.org
dgram inet6 udp 2001:4f8:3:7:2e0:81ff:fe52:9ab6 0
dgram inet udp 149.20.53.67 0
stream inet6 tcp 2001:4f8:3:7:2e0:81ff:fe52:9ab6 0
stream inet tcp 149.20.53.67 0
.Ed
The unspecified service manifested as a port number of zero.
.Pp
Look up
.Dq morden.NetBSD.org
for stream sockets on port 80, and show the canonical name:
.Bd -literal -offset indent
$ getaddrinfo -c -t stream -s 80 morden.NetBSD.org
canonname ftp.NetBSD.org
stream inet6 tcp 2001:470:1f05:3d::21 80
stream inet tcp 199.233.217.249 80
.Ed
.Sh SEE ALSO
.Xr dig 1 ,
.Xr getent 1 ,
.Xr getaddrinfo 3 ,
.Xr getnameinfo 3 ,
.Xr resolver 3 ,
.Xr hosts 5 ,
.Xr nsswitch.conf 5 ,
.Xr protocols 5 ,
.Xr resolv.conf 5 ,
.Xr services 5
.Sh HISTORY
The
.Nm
command first appeared in
.Nx 7.0 .