A Practical Example
This section shows the files that would be needed to implement DNS for a sample Internet-connected network based on the examples used in this chapter.
Caution - The IP addresses and network numbers used in examples and code samples in this manual are for illustration purposes only. Do not use them as shown because they may have been assigned to an actual network or host.
This practical example assumes:
Example Network Domain and Zone Configuration
Name and Zone
| Number
|
|---|
doc.com
| 123.45.6
|
sales.doc.com
| 111.22.3
|
Example Network DNS Servers
Zone
| Host Name
| Function
| Address
| CNAME |
|---|
doc.com
| sirius
| primary for doc.com
| 123.45.6.1
| dnsmaster |
doc.com
| deneb
| secondary for doc.com
| 111.22.3.5
| dnssecond |
sales.doc.com
| altair
| primary for sales.doc.com
| 111.22.3.4
| dnssales |
sales.doc.com
| altair
| secondaryfor sales.doc.com
| 123.45.6.1
| dnsmaster |
Example Boot Files
The following code examples show boot files for the three servers in the two networks:
Example Boot File for dnsmastr Server
; named.boot file on the dnsmastr (sirius)
;
; files required by in.named are located here
directory /var/named
; here are the names of the primary files
cache . named.ca
primary doc.com db.doc
primary 0.0.127.in-addr.arpa named.local
primary 6.45.123.in-addr.arpa doc.rev
;This system is also the secondary for the sales.doc.com domain
secondary sales.doc.com 111.22.3.4 db.sales
secondary 3.22.111.in-addr.arpa 111.22.3.4 sales.rev
|
Example Boot File for dnssales Server
; named.boot file on the dnssales (altair)
;
; in.named is located here
directory /var/named
; here are the names of the primary files
cache . named.ca
primary sales.doc.com db.sales
primary 0.0.127.in-addr.arpa db.127.0.0
primary 3.22.111.in-addr.arpa db.192.168.8
|
Example Boot File for dnssecond Server
; named.boot file on the dnsecond (deneb)
directory /var/named
cache . named.ca
secondary doc.com 123.45.6.1 doc.com
secondary 6.45.123.in-addr.arpa 123.45.6.1 doc.123.45.6
|
Example resolv.conf Files
The following code examples show resolv.conf files for the three servers in the two networks. (If the host in question is not running in.named, the local host address should not be used as a name server.)
Example resolve.conf File for dnsmastr Server
;
; /etc/resolv.conf file for dnsmaster (sirius)
;
domain doc.com
nameserver 0.0.0.0
nameserver 111.22.3.5
|
Example resolve.conf File for dnssales Server
;
; /etc/resolv.conf file for dnssales (altair)
;
domain sales.doc.com
nameserver 111.22.3.4
nameserver 123.45.6.1
|
Example resolve.conf File for dnssecond Server
;
; /etc/resolv.conf for dnssecond
;
domain doc.com
nameserver 111.22.3.5
nameserver 123.45.6.1
|
Example named.local File
The following code example shows the named.local file used by the two primary servers on the two networks. Both servers have the same file.
Example named.local File for Both Primary Servers
; SOA rec
0.0.127.in-addr.arpa. IN SOA siriusdoc.com. sysop.centauri.doc.com. (
19970331 ; serial number
10800 ; refresh every 3 hours
10800 ; retry every 3 hours
604800 ; expire after a week
86400 ) ; TTL of 1 day
; Name Servers
0.0.127.in-addr.arpa. IN NS sirius.doc.com.
0.0.127.in_addr.arpa IN NS dnssecond.doc.com
1 IN PTR localhost.
|
Example hosts Files
The following code examples show db.doc and db.sales files for the two primary servers on the two networks.
Example db.doc File for dnsmastr server
; SOA rec
doc.com. IN SOA sirius.doc.com. sysop.centauri.doc.com. (
19970332 ; serial number
10800 ; refresh every 3 hours
10800 ; retry every 3 hours
604800 ; expire after a week
86400 ) ; TTL of 1 day
; Name Servers
doc.com. IN NS sirius.doc.com.
sales.doc.com. IN NS altair.sales.doc.com.
; Addresses
localhost IN A 127.0.0.1
sirius IN A 123.45.6.1
rigel IN A 123.45.6.112
antares IN A 123.45.6.90
polaris IN A 123.45.6.101
procyon IN A 123.45.6.79
tauceti IN A 123.45.6.69
altair.sales.doc.com. IN A 111.22.3.4
; aliases
dnsmastr IN CNAME sirius.doc.com.
dnssecond.doc.com IN CNAME deneb.doc.com
|
Example db.sales File for dnssales server
; SOA rec
sales.doc.com. IN SOA altair.sales.doc.com. sysop.polaris.doc.com. (
19970332 ; serial number
10800 ; refresh every 3 hours
10800 ; retry every 3 hours
604800 ; expire after a week
86400 ) ; TTL of 1 day
; Name Servers
doc.com. IN NS sirius.doc.com.
sales.doc.com. IN NS altair.sales.doc.com.
; Addresses
altair IN A 111.22.3.4
localhost IN A 127.0.0.1
sirius.doc.com. IN A 123.45.6.1
luna IN A 192.168.8.22
phoebus IN A 192.168.8.24
deimos IN A 192.168.8.25
ganymede IN A 192.168.8.27
europa IN A 192.168.8.28
callisto IN A 192.168.8.29
;
; aliases
dnssales.sales.doc.com IN CNAME altair.sales.doc.com
|
Example hosts.rev Files
The following code examples show hosts.rev files for the two primary servers on the two networks:
Example doc.rev File for dnsmastr server
; SOA rec
6.45.123.in-addr.arpa. IN SOA sirius.doc.com. sysop.centauri.doc.com. (
19970331 ; serial number
10800 ; refresh every 3 hours
10800 ; retry every 3 hours
604800 ; expire after a week
86400 ) ; TTL of 1 day
; Name Servers
6.45.123.in-addr.arpa. IN NS sirius.doc.com.
;Pointer records for 123.45.6
1 IN PTR sirius.doc.com.
112 IN PTR rigel.doc.com.
90 IN PTR antares.doc.com.
101 IN PTR polaris.doc.com.
79 IN PTR procyon.doc.com.
69 IN PTR tauceti.doc.com.
|
Example hosts.rev File for dnssales Server
; SOA rec
3.22.111.in-addr.arpa. IN SOA altair.sales.doc.com. sysop.polaris.doc.com. (
19970331 ; serial number
10800 ; refresh every 3 hours
10800 ; retry every 3 hours
604800 ; expire after a week
86400 ) ; TTL of 1 day
; Name Servers
3.22.111.in-addr.arpa. IN NS altair.sales.doc.com.
;Pointer records for 111.22.3
22 IN PTR luna
23 IN PTR deneb
24 IN PTR phoebus
25 IN PTR deimos
26 IN PTR altair
27 IN PTR ganymede
28 IN PTR europa
29 IN PTR callisto
|
Example name.ca File
The following code example shows the named.ca file that is stored on each of the two primary servers on the two networks. Both servers use identical named.ca files.
Example named.ca File
;
; formerly NS1.ISI.EDU
. 3600000 NS B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET. 3600000 A 128.9.0.107
;
; formerly C.PSI.NET
. 3600000 NS C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12
;
; formerly TERP.UMD.EDU
. 3600000 NS D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90
;
; formerly NS.NASA.GOV
;. 3600000 NS E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10
;
; formerly NS.ISC.ORG
. 3600000 NS F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241
;
; formerly NS.NIC.DDN.MIL
. 3600000 NS G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
. 3600000 NS H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53
;
; formerly NIC.NORDU.NET
. 3600000 NS I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17
;
; temporarily housed at NSI (InterNIC)
. 3600000 NS J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET. 3600000 A 198.41.0.10
;
; temporarily housed at NSI (InterNIC)
. 3600000 NS K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET. 3600000 A 198.41.0.11
;
; temporarily housed at ISI (IANA)
. 3600000 NS L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
;
; temporarily housed at ISI (IANA)
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 198.32.65.12
; End of File
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