mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-12-04 18:59:37 +00:00
208 lines
6.5 KiB
Plaintext
208 lines
6.5 KiB
Plaintext
@(#) README.NIS 1.2 96/02/11 17:24:52
|
|
|
|
> Problem: I have several [machines] with multiple IP addresses, and
|
|
> when they try to connect to a daemon with tcp wrapper, they are often
|
|
> rejected. I assume this is due to the -DPARANOID option, and depends
|
|
> on which IP address is returned first from the nameserver for a given
|
|
> name. This behavior seems to be random, may depend on ordering in
|
|
> the YP host map?
|
|
|
|
[Note: the situation described below no longer exists. Presently, my
|
|
internet gateway uses the same IP address on all interfaces. To avoid
|
|
confusion I have removed the old name wzv-gw.win.tue.nl from the DNS. I
|
|
have kept the discussion below for educational reasons].
|
|
|
|
NIS was not designed to handle multi-homed hosts. With NIS, each
|
|
address should have its own hostname. For example, wzv-gw is my
|
|
gateway. It has two interfaces: one connected to the local ethernet,
|
|
the other to a serial link. In the NIS it is registered as:
|
|
|
|
131.155.210.23 wzv-gw-ether
|
|
131.155.12.78 wzv-gw-slip
|
|
|
|
In principle, wzv-gw could be the official name of one of these
|
|
interfaces, or it could be an alias for both.
|
|
|
|
The DNS was designed to handle multi-homed hosts. In the DNS my gateway
|
|
is registered in zone win.tue.nl, with one name that has two A records:
|
|
|
|
wzv-gw IN A 131.155.210.23
|
|
IN A 131.155.12.78
|
|
|
|
And of course there are PTR records in zones 210.155.131.in-addr.arpa
|
|
and 12.155.131.in-addr.arpa that point to wzv-gw.win.tue.nl.
|
|
|
|
This setup does not cause any problems. You can test your name service
|
|
with the two programs below. This is what they say on a local NIS client
|
|
(both client and server running SunOS 4.1.3_U1):
|
|
|
|
% gethostbyname wzv-gw
|
|
Hostname: wzv-gw.win.tue.nl
|
|
Aliases:
|
|
Addresses: 131.155.210.23 131.155.12.78
|
|
|
|
% gethostbyaddr 131.155.210.23
|
|
Hostname: wzv-gw-ether
|
|
Aliases:
|
|
Addresses: 131.155.210.23
|
|
|
|
% gethostbyaddr 131.155.12.78
|
|
Hostname: wzv-gw-slip
|
|
Aliases:
|
|
Addresses: 131.155.12.78
|
|
|
|
Things seem less confusing when seen by a NIS client in a different
|
|
domain (both client and server running SunOS 4.1.3_U1):
|
|
|
|
% gethostbyname wzv-gw.win.tue.nl
|
|
Hostname: wzv-gw.win.tue.nl
|
|
Aliases:
|
|
Addresses: 131.155.210.23 131.155.12.78
|
|
|
|
% gethostbyaddr 131.155.210.23
|
|
Hostname: wzv-gw.win.tue.nl
|
|
Aliases:
|
|
Addresses: 131.155.12.78 131.155.210.23
|
|
|
|
% gethostbyaddr 131.155.12.78
|
|
Hostname: wzv-gw.win.tue.nl
|
|
Aliases:
|
|
Addresses: 131.155.210.23 131.155.12.78
|
|
|
|
Alas, Solaris 2.4 still has problems. This is what I get on a Solaris
|
|
2.4 NIS client, with a SunOS 4.1.3_U1 NIS server:
|
|
|
|
% gethostbyname wzv-gw.win.tue.nl
|
|
Hostname: wzv-gw.win.tue.nl
|
|
Aliases: 131.155.210.23 wzv-gw.win.tue.nl
|
|
Addresses: 131.155.12.78
|
|
|
|
The tcpd source comes with a workaround for this problem. The
|
|
workaround is ugly and is not part of the programs attached below.
|
|
|
|
|
|
#! /bin/sh
|
|
# This is a shell archive. Remove anything before this line, then unpack
|
|
# it by saving it into a file and typing "sh file". To overwrite existing
|
|
# files, type "sh file -c". You can also feed this as standard input via
|
|
# unshar, or by typing "sh <file", e.g.. If this archive is complete, you
|
|
# will see the following message at the end:
|
|
# "End of shell archive."
|
|
# Contents: gethostbyaddr.c gethostbyname.c
|
|
# Wrapped by wietse@wzv on Sun Jan 8 17:08:48 1995
|
|
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
|
|
if test -f gethostbyaddr.c -a "${1}" != "-c" ; then
|
|
echo shar: Will not over-write existing file \"gethostbyaddr.c\"
|
|
else
|
|
echo shar: Extracting \"gethostbyaddr.c\" \(1073 characters\)
|
|
sed "s/^X//" >gethostbyaddr.c <<'END_OF_gethostbyaddr.c'
|
|
X /*
|
|
X * gethostbyaddr tester. compile with:
|
|
X *
|
|
X * cc -o gethostbyaddr gethostbyaddr.c (SunOS 4.x)
|
|
X *
|
|
X * cc -o gethostbyaddr gethostbyaddr.c -lnsl (SunOS 5.x)
|
|
X *
|
|
X * run as: gethostbyaddr address
|
|
X *
|
|
X * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
|
|
X */
|
|
X
|
|
X#include <sys/types.h>
|
|
X#include <sys/socket.h>
|
|
X#include <netinet/in.h>
|
|
X#include <arpa/inet.h>
|
|
X#include <netdb.h>
|
|
X#include <stdio.h>
|
|
X
|
|
Xmain(argc, argv)
|
|
Xint argc;
|
|
Xchar **argv;
|
|
X{
|
|
X struct hostent *hp;
|
|
X long addr;
|
|
X
|
|
X if (argc != 2) {
|
|
X fprintf(stderr, "usage: %s i.p.addres\n", argv[0]);
|
|
X exit(1);
|
|
X }
|
|
X addr = inet_addr(argv[1]);
|
|
X if (hp = gethostbyaddr((char *) &addr, sizeof(addr), AF_INET)) {
|
|
X printf("Hostname:\t%s\n", hp->h_name);
|
|
X printf("Aliases:\t");
|
|
X while (hp->h_aliases[0])
|
|
X printf("%s ", *hp->h_aliases++);
|
|
X printf("\n");
|
|
X printf("Addresses:\t");
|
|
X while (hp->h_addr_list[0])
|
|
X printf("%s ", inet_ntoa(*(struct in_addr *) * hp->h_addr_list++));
|
|
X printf("\n");
|
|
X exit(0);
|
|
X }
|
|
X fprintf(stderr, "host %s not found\n", argv[1]);
|
|
X exit(1);
|
|
X}
|
|
END_OF_gethostbyaddr.c
|
|
if test 1073 -ne `wc -c <gethostbyaddr.c`; then
|
|
echo shar: \"gethostbyaddr.c\" unpacked with wrong size!
|
|
fi
|
|
# end of overwriting check
|
|
fi
|
|
if test -f gethostbyname.c -a "${1}" != "-c" ; then
|
|
echo shar: Will not over-write existing file \"gethostbyname.c\"
|
|
else
|
|
echo shar: Extracting \"gethostbyname.c\" \(999 characters\)
|
|
sed "s/^X//" >gethostbyname.c <<'END_OF_gethostbyname.c'
|
|
X /*
|
|
X * gethostbyname tester. compile with:
|
|
X *
|
|
X * cc -o gethostbyname gethostbyname.c (SunOS 4.x)
|
|
X *
|
|
X * cc -o gethostbyname gethostbyname.c -lnsl (SunOS 5.x)
|
|
X *
|
|
X * run as: gethostbyname hostname
|
|
X *
|
|
X * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
|
|
X */
|
|
X#include <sys/types.h>
|
|
X#include <sys/socket.h>
|
|
X#include <netinet/in.h>
|
|
X#include <arpa/inet.h>
|
|
X#include <netdb.h>
|
|
X#include <stdio.h>
|
|
X
|
|
Xmain(argc, argv)
|
|
Xint argc;
|
|
Xchar **argv;
|
|
X{
|
|
X struct hostent *hp;
|
|
X
|
|
X if (argc != 2) {
|
|
X fprintf(stderr, "usage: %s hostname\n", argv[0]);
|
|
X exit(1);
|
|
X }
|
|
X if (hp = gethostbyname(argv[1])) {
|
|
X printf("Hostname:\t%s\n", hp->h_name);
|
|
X printf("Aliases:\t");
|
|
X while (hp->h_aliases[0])
|
|
X printf("%s ", *hp->h_aliases++);
|
|
X printf("\n");
|
|
X printf("Addresses:\t");
|
|
X while (hp->h_addr_list[0])
|
|
X printf("%s ", inet_ntoa(*(struct in_addr *) * hp->h_addr_list++));
|
|
X printf("\n");
|
|
X exit(0);
|
|
X } else {
|
|
X fprintf(stderr, "host %s not found\n", argv[1]);
|
|
X exit(1);
|
|
X }
|
|
X}
|
|
END_OF_gethostbyname.c
|
|
if test 999 -ne `wc -c <gethostbyname.c`; then
|
|
echo shar: \"gethostbyname.c\" unpacked with wrong size!
|
|
fi
|
|
# end of overwriting check
|
|
fi
|
|
echo shar: End of shell archive.
|
|
exit 0
|