From Linux NFS

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Revision as of 03:23, 20 July 2011

This document describes the basic setup of a fake DNS domain for use in testing NFSv4 (Kerberos, etc).

To use a fake DNS domain, you must run a named server locally and configure all of the clients to use it as their only nameserver.

Contents 1 Install and configure a server for the fake DNS domain 1.1 Install named on the server 1.2 Configure the DNS zone 1.3 Configure the reverse mapping 1.4 Modify named config 1.5 Restart named 2 Configure the client(s) and server to use the local DNS server

Install and configure a server for the fake DNS domain

DNS domain: example.fake

Hosts:

• server.example.fake (192.168.56.20)
• client1.example.fake (192.168.56.40)

Install named on the server

 [root@server ~]# sudo yum install bind

Configure the DNS zone

This creates a DNS zone for "example.fake".

Three services are defined for use with FreeIPA (XXX link??).

Create the file "/var/named/example.fake.zone":

$TTL 3D
@       IN      SOA     ns1.example.fake. hostmaster.example.fake. (
                       201107111       ; serial#
                       3600            ; refresh, seconds
                       3600            ; retry, seconds
                       3600            ; expire, seconds
                       3600 )          ; minimum, seconds

                NS      ns1             ; Inet Address of nameserver
example.fake.   MX      10 mail         ; Primary Mail Exchanger

ns1             A       192.168.56.20
server          A       192.168.56.20

client1         A       192.168.56.40

ipa             CNAME   build

; DNS auto discovery of services
_ldap._tcp      SRV 10 10 389 server.example.fake.
_kerberos._udp  SRV 10 10 88 server.example.fake.
_kerberos._tcp  SRV 10 10 88 server.example.fake.

Configure the reverse mapping

Create the file "/var/named/192-168-56.zone":

$TTL 2d  ; 172800 seconds
$ORIGIN 56.168.192.IN-ADDR.ARPA.
@       IN        SOA        ns1.example.fake.  hostmaster.example.fake. (
                            201107111          ; serial number
                            3600               ; refresh, seconds
                            3600               ; retry, seconds
                            3600               ; expire, seconds
                            3600 )             ; minimum, seconds

                IN      NS      ns1.example.fake.
20              IN      PTR     server.example.fake.
40              IN      PTR     client1.example.fake.

Modify named config

Add these sections to file "/etc/named.conf":

zone "example.fake" IN {
	type master;
	file "example.fake.zone";
};

zone "56.168.192.in-addr.arpa" IN {
	type master;
	file "192-168-56.zone";
};

There are a few other things that I needed to configure in my test setup. You probably don't want to turn off dnssec in real world setups!

In the "options" section:

• change the "listen-on" option to include the server's external address ""{ localhost; 192.168.56.20; }"
• change "allow-query" option to "{ localhost; 192.168.56.0/24 }"
• change "dnssec-enable" option to "no"
• change "dnssec-validation" option to "no"

The resulting /etc/named.conf:

//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//

options {
	listen-on port 53 { 127.0.0.1; 192.168.56.20; };
	listen-on-v6 port 53 { ::1; };
	directory 	"/var/named";
	dump-file 	"/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
	allow-query     { localhost; 192.168.56.0/24; };
	recursion yes;

	dnssec-enable yes;
	dnssec-validation no;
	dnssec-lookaside auto;

	/* Path to ISC DLV key */
	bindkeys-file "/etc/named.iscdlv.key";

	managed-keys-directory "/var/named/dynamic";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "." IN {
	type hint;
	file "named.ca";
};

zone "example.fake" IN {
        type master;
        file "example.fake.zone";
};

zone "56.168.192.in-addr.arpa" IN {
        type master;
        file "192-168-56.zone";
};

include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

Restart named

[root@server ~]# service named restart
Restarting named (via systemctl):                          [  OK  ]

Configure the client(s) and server to use the local DNS server

The server and all clients should use this name server (with this testing environment). With a real DNS server, clients shouldn't require this configuration.

Edit file "/etc/sysconfig/network-scripts/ifcfg-eth0" (or whatever is appropriate) and change the DNS1 line to:

DNS1=192.168.56.20

Restart the network service to pick up the change.

[root@server ~]# service network restart
Restarting network (via systemctl):                        [  OK  ]

And verify that it worked:

[root@server ~]# cat /etc/resolv.conf 
# Generated by NetworkManager
search example.fake
nameserver 192.168.56.20

[root@server ~]# nslookup server.example.fake
Server:		192.168.56.20
Address:	192.168.56.20#53

Name:	server.example.fake
Address: 192.168.56.20