00b67f09dd
Also known as ISC bind. This import adds utilities such as host(1), dig(1), and nslookup(1), as well as many other tools and libraries. Change-Id: I035ca46e64f1965d57019e773f4ff0ef035e4aa3
209 lines
5.5 KiB
Groff
209 lines
5.5 KiB
Groff
.\" $NetBSD: lwres_getipnode.3,v 1.5 2014/12/10 04:38:02 christos Exp $
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.\"
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.\" Copyright (C) 2004, 2005, 2007, 2014 Internet Systems Consortium, Inc. ("ISC")
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.\" Copyright (C) 2000, 2001, 2003 Internet Software Consortium.
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.\"
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.\" Permission to use, copy, modify, and/or distribute this software for any
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.\" purpose with or without fee is hereby granted, provided that the above
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.\" copyright notice and this permission notice appear in all copies.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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.\" REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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.\" AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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.\" INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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.\" LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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.\" OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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.\" PERFORMANCE OF THIS SOFTWARE.
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.\"
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.\" Id
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.\"
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.hy 0
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.ad l
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.\" Title: lwres_getipnode
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.\" Author:
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.\" Generator: DocBook XSL Stylesheets v1.71.1 <http://docbook.sf.net/>
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.\" Date: June 18, 2007
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.\" Manual: BIND9
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.\" Source: BIND9
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.\"
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.TH "LWRES_GETIPNODE" "3" "June 18, 2007" "BIND9" "BIND9"
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.\" disable hyphenation
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.nh
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.\" disable justification (adjust text to left margin only)
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.ad l
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.SH "NAME"
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lwres_getipnodebyname, lwres_getipnodebyaddr, lwres_freehostent \- lightweight resolver nodename / address translation API
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.SH "SYNOPSIS"
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.nf
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#include <lwres/netdb.h>
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.fi
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.HP 39
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.BI "struct hostent * lwres_getipnodebyname(const\ char\ *" "name" ", int\ " "af" ", int\ " "flags" ", int\ *" "error_num" ");"
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.HP 39
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.BI "struct hostent * lwres_getipnodebyaddr(const\ void\ *" "src" ", size_t\ " "len" ", int\ " "af" ", int\ *" "error_num" ");"
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.HP 23
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.BI "void lwres_freehostent(struct\ hostent\ *" "he" ");"
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.SH "DESCRIPTION"
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.PP
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These functions perform thread safe, protocol independent nodename\-to\-address and address\-to\-nodename translation as defined in RFC2553.
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.PP
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They use a
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\fBstruct hostent\fR
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which is defined in
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\fInamedb.h\fR:
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.PP
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.RS 4
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.nf
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struct hostent {
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char *h_name; /* official name of host */
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char **h_aliases; /* alias list */
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int h_addrtype; /* host address type */
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int h_length; /* length of address */
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char **h_addr_list; /* list of addresses from name server */
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};
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#define h_addr h_addr_list[0] /* address, for backward compatibility */
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.fi
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.RE
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.sp
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.PP
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The members of this structure are:
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.PP
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\fBh_name\fR
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.RS 4
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The official (canonical) name of the host.
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.RE
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.PP
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\fBh_aliases\fR
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.RS 4
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A NULL\-terminated array of alternate names (nicknames) for the host.
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.RE
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.PP
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\fBh_addrtype\fR
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.RS 4
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The type of address being returned \- usually
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\fBPF_INET\fR
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or
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\fBPF_INET6\fR.
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.RE
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.PP
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\fBh_length\fR
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.RS 4
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The length of the address in bytes.
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.RE
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.PP
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\fBh_addr_list\fR
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.RS 4
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A
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\fBNULL\fR
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terminated array of network addresses for the host. Host addresses are returned in network byte order.
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.RE
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.PP
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\fBlwres_getipnodebyname()\fR
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looks up addresses of protocol family
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\fIaf\fR
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for the hostname
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\fIname\fR. The
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\fIflags\fR
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parameter contains ORed flag bits to specify the types of addresses that are searched for, and the types of addresses that are returned. The flag bits are:
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.PP
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\fBAI_V4MAPPED\fR
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.RS 4
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This is used with an
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\fIaf\fR
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of AF_INET6, and causes IPv4 addresses to be returned as IPv4\-mapped IPv6 addresses.
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.RE
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.PP
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\fBAI_ALL\fR
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.RS 4
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This is used with an
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\fIaf\fR
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of AF_INET6, and causes all known addresses (IPv6 and IPv4) to be returned. If AI_V4MAPPED is also set, the IPv4 addresses are return as mapped IPv6 addresses.
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.RE
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.PP
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\fBAI_ADDRCONFIG\fR
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.RS 4
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Only return an IPv6 or IPv4 address if here is an active network interface of that type. This is not currently implemented in the BIND 9 lightweight resolver, and the flag is ignored.
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.RE
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.PP
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\fBAI_DEFAULT\fR
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.RS 4
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This default sets the
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\fBAI_V4MAPPED\fR
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and
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\fBAI_ADDRCONFIG\fR
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flag bits.
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.RE
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.PP
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\fBlwres_getipnodebyaddr()\fR
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performs a reverse lookup of address
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\fIsrc\fR
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which is
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\fIlen\fR
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bytes long.
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\fIaf\fR
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denotes the protocol family, typically
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\fBPF_INET\fR
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or
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\fBPF_INET6\fR.
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.PP
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\fBlwres_freehostent()\fR
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releases all the memory associated with the
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\fBstruct hostent\fR
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pointer
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\fIhe\fR. Any memory allocated for the
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\fBh_name\fR,
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\fBh_addr_list\fR
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and
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\fBh_aliases\fR
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is freed, as is the memory for the
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\fBhostent\fR
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structure itself.
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.SH "RETURN VALUES"
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.PP
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If an error occurs,
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\fBlwres_getipnodebyname()\fR
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and
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\fBlwres_getipnodebyaddr()\fR
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set
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\fI*error_num\fR
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to an appropriate error code and the function returns a
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\fBNULL\fR
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pointer. The error codes and their meanings are defined in
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\fI<lwres/netdb.h>\fR:
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.PP
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\fBHOST_NOT_FOUND\fR
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.RS 4
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No such host is known.
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.RE
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.PP
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\fBNO_ADDRESS\fR
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.RS 4
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The server recognised the request and the name but no address is available. Another type of request to the name server for the domain might return an answer.
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.RE
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.PP
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\fBTRY_AGAIN\fR
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.RS 4
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A temporary and possibly transient error occurred, such as a failure of a server to respond. The request may succeed if retried.
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.RE
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.PP
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\fBNO_RECOVERY\fR
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.RS 4
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An unexpected failure occurred, and retrying the request is pointless.
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.RE
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.PP
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\fBlwres_hstrerror\fR(3)
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translates these error codes to suitable error messages.
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.SH "SEE ALSO"
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.PP
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\fBRFC2553\fR(),
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\fBlwres\fR(3),
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\fBlwres_gethostent\fR(3),
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\fBlwres_getaddrinfo\fR(3),
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\fBlwres_getnameinfo\fR(3),
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\fBlwres_hstrerror\fR(3).
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.SH "COPYRIGHT"
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Copyright \(co 2004, 2005, 2007, 2014 Internet Systems Consortium, Inc. ("ISC")
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.br
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Copyright \(co 2000, 2001, 2003 Internet Software Consortium.
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.br
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