xref: /freebsd/usr.bin/getaddrinfo/getaddrinfo.1 (revision 389e4940069316fe667ffa263fa7d6390d0a960f)
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2.\"	$NetBSD: getaddrinfo.1,v 1.5 2014/04/22 06:02:06 wiz Exp $
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31.Dd March 20, 2017
32.Dt GETADDRINFO 1
33.Os
34.Sh NAME
35.Nm getaddrinfo
36.Nd resolve names to socket addresses
37.Sh SYNOPSIS
38.Nm
39.Op Fl cNnP
40.Op Fl f Ar family
41.Op Fl p Ar protocol
42.Op Fl s Ar service Ns Op Ns / Ns Ar protocol
43.Op Fl t Ar socktype
44.Op Ar hostname
45.Sh DESCRIPTION
46The
47.Nm
48utility resolves host and service names to socket addresses with
49.Xr getaddrinfo 3
50and prints them to standard output in a user-friendly format.
51.Pp
52The output is a sequence of lines with space-separated fields:
53.Pp
54.Dl socket-type address-family protocol [af-specific data ...]
55.Pp
56For the
57.Dq inet
58and
59.Dq inet6
60address families, the af-specific data are the IP/IPv6 address and port
61number.
62.Pp
63Depending on the settings in
64.Xr nsswitch.conf 5 ,
65.Nm
66might query DNS for answers.
67However, it is not intended to be a general-purpose DNS query utility.
68Use
69.Xr drill 1
70for that.
71.Pp
72These options are available:
73.Bl -tag -width Ds
74.It Fl c
75Look up a canonical name as if with the
76.Dv AI_CANONNAME
77flag to
78.Xr getaddrinfo 3
79and print it on the first line before the socket addresses.
80.It Fl f Ar family
81Specify an address family.
82Address families are named like the
83.Dv AF_...
84constants for address family numbers in the
85.Aq Pa sys/socket.h
86header file but without the
87.Dv AF_
88prefix and lowercase.
89For example,
90.Dq inet
91corresponds with
92.Dv AF_INET .
93.It Fl N
94Treat the service as numeric and do not attempt service name
95resolution, as if with the
96.Dv AI_NUMERICSERV
97flag to
98.Xr getaddrinfo 3 .
99.It Fl n
100Treat the hostname as a numeric address and do not attempt name
101resolution, as if with the
102.Dv AI_NUMERICHOST
103flag to
104.Xr getaddrinfo 3 .
105.It Fl P
106Return socket addresses intended for use with
107.Xr bind 2 ,
108as if with the
109.Dv AI_PASSIVE
110flag to
111.Xr getaddrinfo 3 .
112By default, the socket addresses are intended for use with
113.Xr connect 2 ,
114.Xr sendto 2 ,
115or
116.Xr sendmsg 2 .
117.It Fl p Ar protocol
118Specify a protocol.
119Protocols are numeric or symbolic as listed in
120.Xr protocols 5 .
121.It Fl s Ar service Ns Op Ns / Ns Ar protocol
122Specify a service to look up.
123Services are symbolic or numeric with an optional
124protocol suffix as listed in
125.Xr services 5 .
126If a service is not specified, a hostname is required.
127.It Fl t Ar socktype
128Specify a socket type.
129Socket types are named like the
130.Dv SOCK_...
131constants for socket type numbers in the
132.Aq Pa sys/socket.h
133header file but without the
134.Dv SOCK_
135prefix and lowercase.
136For example,
137.Dq dgram
138corresponds with
139.Dv SOCK_DGRAM .
140.El
141.Sh EXIT STATUS
142.Ex -std getaddrinfo
143.Sh EXAMPLES
144Look up
145.Dq www.NetBSD.org :
146.Bd -literal -offset indent
147$ getaddrinfo www.NetBSD.org
148dgram inet6 udp 2001:4f8:3:7:2e0:81ff:fe52:9ab6 0
149dgram inet udp 149.20.53.67 0
150stream inet6 tcp 2001:4f8:3:7:2e0:81ff:fe52:9ab6 0
151stream inet tcp 149.20.53.67 0
152.Ed
153.Pp
154The port number here is zero because no service was specified.
155.Pp
156Look up
157.Dq morden.NetBSD.org
158for stream sockets on port 80, and show the canonical name:
159.Bd -literal -offset indent
160$ getaddrinfo -c -t stream -s 80 morden.NetBSD.org
161canonname ftp.NetBSD.org
162stream inet6 tcp 2001:470:1f05:3d::21 80
163stream inet tcp 199.233.217.249 80
164.Ed
165.Sh SEE ALSO
166.Xr drill 1 ,
167.Xr getent 1 ,
168.Xr getaddrinfo 3 ,
169.Xr getnameinfo 3 ,
170.Xr resolver 3 ,
171.Xr hosts 5 ,
172.Xr nsswitch.conf 5 ,
173.Xr protocols 5 ,
174.Xr resolv.conf 5 ,
175.Xr services 5
176.Sh HISTORY
177The
178.Nm
179command first appeared in
180.Nx 7.0 .
181