.\"	$NetBSD: getaddrinfo.1,v 1.5 2014/04/22 06:02:06 wiz Exp $
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.\" Copyright (c) 2013 The NetBSD Foundation, Inc.
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.\" This documentation is derived from text contributed to The NetBSD
.\" Foundation by Taylor R. Campbell.
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.Dd April 22, 2014
.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 Ns Op Ns / Ns Ar protocol
.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:
.Pp
.Dl socket-type address-family protocol [af-specific data ...]
.Pp
For the
.Dq inet
and
.Dq inet6
address families, the af-specific data are the IP/IPv6 address and 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 Ns Op Ns / Ns Ar protocol
Specify a service to look up.
Services may be symbolic or numeric with an optional
protocol suffix as listed in
.Xr services 5 .
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
.Pp
The port number here is zero because no service was specified.
.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 .