DNS: dns4-exercise2.2.txt

File dns4-exercise2.2.txt, 5.6 KB (added by scg, 9 years ago)
Reverse DNS exercise

Line
1	DNS Exercise 4.2: Setting up Reverse DNS (in-addr.arpa.) for a /24 IP Block
2	===========================================================================
3
4	Since we don't have an entire /24 for the class, we'll pretend we have
5	one for each student.
6
7	We'll use 192.168.0.0/16 for reverse DNS (in-addr.arpa.) exercises
8	in this workshop.
9
10	Each student will be allocated a /24 for this exercise. Each student will
11	setup reverse DNS for the /24 allocated to them. The allocation will be
12	done based on the students PCs number so if your PC is `ws1.ws3.conference.sanog.org`,
13	and your IP address is `119.2.100.1`, then the /24 assigned to you will be
14	`192.168.1.0/24`.
15
16	In this exercise, you will setup reverse DNS for 192.168.X.0/24, where X
17	is your PCs number. You will create master nameservice on your own machine,
18	and someone else will setup their machine to be a slave server for your
19	X.222.196.in-addr.arpa. domain. Then you will ask the administrator for the
20	domain (your RIR in real life) above you (222.196.in-addr.arpa) to delegate
21	the /24 to you.
22
23	Please refer to DNS Exercise 3.1 on Setting up a domain
24
25
26	Exercise
27	--------
28
29	* Write the domain allocated to you here: `____.222.196.in-addr.arpa.`
30	(e.g. ws12 will write 12.222.196.in-addr.arpa.)
31
32	* Find someone who will agree to be slave for your domain. You must choose
33	someone on a DIFFERENT table to you. (Remember RFC2182: secondaries must
34	be on remote networks). You can have more than one slave if you wish.
35
36	* Create your zone file in `/var/named/etc/namedb/master/X.222.196.in-addr.arpa`
37	(where X is your PCs number)
38
39	> $TTL 10m
40	> @ IN SOA wsX.ws3.conference.sanog.org. yourname.example.com. (
41	> 2006051000 ; Serial
42	> 10m ; Refresh
43	> 10m ; Retry
44	> 4w ; Expire
45	> 10m ) ; Negative
46	>
47	> IN NS wsX.ws3.conference.sanog.org. ; master
48	> IN NS wsY.ws3.conference.sanog.org. ; slave
49	>
50	> 1 IN PTR dhcp1.xxxxx.ws3.conference.sanog.org.
51	>
52	> $GENERATE 11-254 $ IN PTR ppp$.xxxxx.ws3.conference.sanog.org.
53
54	Replace `yourname.example.com.` with your home E-mail address, changing
55	"@" to "." and adding a "." to the end.
56
57	Replace xxxxx.ws3.conference.sanog.org with the domain you setup in
58	DNS Exercise 3.1: Setting up a domain
59
60	We have chosen purposely low values for TTL, refresh, and retry to make
61	it easier to fix problems in the classroom. For a production domain you
62	would use higher values, e.g. `$TTL 1d`
63
64	* Edit `/var/named/etc/namedb/named.conf` to configure your machine as
65	master for your domain (see slides for information how to do this)
66
67	* Check that your config file and zone file are valid, and then reload the
68	nameserver daemon:
69
70	# named-checkconf
71	# named-checkzone X.222.196.in-addr.arpa \
72	/var/named/etc/namedb/master/X.222.196.in-addr.arpa
73
74	If there are any errors, correct them
75
76	# rndc reload
77	# tail /var/log/messages
78
79	If there are any errors, correct them. Some configuration errors can
80	cause the daemon to die completely, in which case you may have to
81	start it again:
82
83	# /etc/rc.d/named restart
84
85	* Assist your slaves to configure themselves as slave for your domain, and
86	configure yourself as a slave if asked to do so by another table.
87	Again, the instructions for how to do this are on the slides. If you
88	have changed your `named.conf` so that you are a slave for someone
89	else, make sure there are no errors in `/var/log/messages` after you
90	do `rndc reload`.
91
92	* Check that you and your slaves are giving authoritative answers for
93	your domain:
94
95	# dig +norec @119.2.100.X X.222.196.in-addr.arpa. soa
96	# dig +norec @192.200.219.Y X.222.196.in-addr.arpa. soa
97
98	Check that you get an AA (authoritative answer) from both, and that
99	the serial numbers match.
100
101	* Now you are ready to request delegation. Bring the following form to the
102	classroom instructor:
103
104	Domain name: __.222.196.in-addr.arpa.
105
106	Master nameserver: ws____.ws3.conference.sanog.org
107
108	Slave nameserver: ws____.ws3.conference.sanog.org
109
110	Slave nameserver: ws____.ws3.conference.sanog.org (optional)
111
112	Slave nameserver: ws____.ws3.conference.sanog.org (optional)
113
114	* You will not get delegation until the instructor has checked:
115
116	- Your nameservers are all authoritative for your domain
117	- They all have the same SOA serial number
118	- The NS records within the zone match the list of servers you are
119	requesting delegation for
120	- The slave(s) are not on the same desk as you
121
122	* Once you have delegation, find the names associated with
123	192.168.X.1 and 192.168.X.12:
124
125	Try this:
126	- On your own machine
127
128	# dig +norec @119.2.100.X -x 192.168.X.1
129	# dig +norec @119.2.100.X -x 192.168.X.12
130
131	- On someone else's machine (who is not slave for you)
132	- On a machine elsewhere on the Internet, if you have access to one
133	(www.dnsstuff.com)
134
135	* Ensure that the forward and reverse DNS entries match. You will have to
136	edit your xxxxx.ws3.conference.sanog.org zonefiles and add the following records. Don't
137	forget to increase the serial number in the zone file.
138
139	> dhcp1 IN A 192.168.X.1
140	>
141	> $GENERATE 11-254 ppp$ IN A 192.168.X.$