Solaris DNS Tutorial, part 1/3

; formerly NS.INTERNIC.NET
;
. 3600000 IN NS A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4
;
; 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 ...
...
; housed in Japan, operated by WIDE
;
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33 ; End of File

Where:

• In the first record:
  • The dot (.) in the first field pertains to the root domain.
  • The time-to-live field is 3600000 seconds. If this field is left blank, the default time-to-live is specified in the SOA resource record.
  • The class IN stands for Internet.
  • The record type NS, indicates a name server is being defined for the root domain.
  • The fifth field of the first record (the data field) is the FQDN (note the trailing dot) of a root name server.
• In the second record:
  • The first (domain) field contains the FQDN of the root server defined in the previous record.
  • The time-to-live field is 3600000 seconds. If this field is left blank, the default time-to-live is specified in the SOA resource record.
  • The record type, A, contains an IP address.
  • For A records, the fifth data field contains the IP address of the domain specified in the first field.

  
  The NS and A type records are combined to define the name and address of a single root server. Additional pairs of records would be specified in this file as appropriate.

/var/named/domain-info File

; Information for the "forward" domain zoo.edu.
;
@ IN SOA horse.zoo.edu. hostmaster.zoo.edu. (
1 ; Serial number
43200 ; Refresh timer - 12 hours 3600 ; Retry timer - 1 hour
;
Define name
servers for this IN NS IN NS IN NS
604800 ; Expire timer - 1 week 86400 ; Time to live - 1 day )
domain.horse.zoo.edu. ; primary pea.veggie.edu. ; secondary tuna.fish.edu. ; secondary

; Glue records - needed for secondaries residing in other domains.
pea.veggie.edu. IN A 128.50.2.1
tuna.fish.edu. IN A 128.50.3.1

; Define name to address mappings for this domain.
lion IN A 128.50.1.250
lion-router IN A 128.50.2.250 # this is a router for rockway
rhino IN A 128. 50 .1.3
mule IN A 128. 50 .1.2
horse IN A 128. 50 .1.1
; CNAME aliases.
nti-router IN CNAME lion-router

; Loopback domain definition (required).

localhost IN A 127.0.0.1

The SOA record

The SOA record is mandatory and has the following items of note:

• An at sign (@) in the domain field - A shortcut for the domain being served (zoo . edu. in this case). The actual value for the @ comes from the second field of the appropriate record in the named. conf file. The @ also serves to define the default origin - that domain appended to any domain name in the configuration file that is not fully qualified.
  
• Data field argument 1 - Name of the primary master server for this domain in FQDN format.
   
• Data field argument 2 - Email address that can be used to report on problems with the domain. The current standards specify this address should be hostmaster@domain. Note the @ is replaced with a dot in the SOA record since the @ has special meaning in this file.
  
• Data field argument 3 - Serial number used by secondary master servers to see if they need to perform a zone transfer, re-acquiring a fresh copy of zone data. Anytime you make changes to this file you must remember to update the serial number in such a manner that it gets larger. Consult DNS & BIND for serial number strategies. (It is always safe to start at one and add one with each change.)
  
• Data field argument 4 - The refresh timer is a time interval, in seconds, after which the secondary master servers should check to see if the serial number has changed and, hence, a new zone transfer needs to occur.
  
• Data field argument 5 - The retry timer is a time interval, in seconds, after which the secondary master servers would check back if a normal refresh failed. This timer is typically set to a smaller value than the refresh timer.
  
  
• Data field argument 6 - The expire timer is a time interval, in seconds, after which, if a secondary is unable to contact the primary server or another secondary server, the entire zone data should be discarded. The secondaries that have lost contact with the rest of the name servers for a zone do not continue to give out potentially out-of-date information indefinitely.
  
  
• Data field argument 7 - The minimum timer is the default time-to-live value given out in normal query replies to servers from remote domains. If the time-to-live value is omitted in the second field of subsequent resource records, this value is used instead.
  
  
• An NS record should be defined for all name servers in this domain that you want the world to know about. For any of these name servers that reside in other domains, you must also define "glue" address records.
  
  
• The remainder of the file contains address records for each host in the domain.
  
  
• Host one has two address records because it is a router.
  
  
• In the second address record for host one, you can omit the name in field 1. With DNS hosts, you can have one name with many addresses. This is in contrast to the operation of the UNIX /etc/inet/hosts file in which each host interface has a different name.
  
  
• Most of the host names are not fully qualified. Those that are not, have the domain name origin (the value of the @ in the SOA record by default) appended to them. This shorthand can save a lot of typing and improve the readability and maintainability of the file.
  
  
• The CNAME record is used to define host aliases or nicknames for hosts. The CNAME in this instance is somewhat analogous to the hosts file fragment 128.50.1.2 mule www.
  
  
• The localhost entry is required for proper functioning of the name server.

/var/named/inverse-domain-info File

This file contains mappings for address to name translation. Address to name translation is important and is used by such varying utilities as NFS, web servers, BIND, and the Berkeley r-command series, to name a few.

@ IN SOA horse.zoo.edu. hostmaster.zoo.edu. (
1 ; Serial number
43200 ; Refresh timer - 12 hours 3600 ; Retry timer - 1 hour 604800 ; Expire timer - 1 week 86400 ; Minimum timer - 1 day )
; Define name servers for this domain.
IN NS horse.zoo.edu.; primary
IN NS pea. veggie. edu.; secondary IN NS tuna.fish.edu.; secondary
; Define address to name mappings for this domain.
250.1.250.128.in-addr.arpa IN PTR lion.zoo.edu.
3 IN PTR rhino.zoo.edu.
2 IN PTR mule.zoo.edu.
1 IN PTR horse.zoo.edu.

Some items of note are:

• The SOA record is as it was in the forward domain file. The @ in this case refers to the inverse domain, however.
  
• The address to name mappings are defined with the PTR record type.
  
• The first domain field contains the number used to complete the fourth octet of the IP address portion of the inverse inaddr. arpa domain.
  
• The first field is always a domain field. Since the domain name here does not end with a dot, it will be completed with the value of the @.
  
• The argument field of the PTR record should contain the FQDN of the name of the host being pointed at. This, in effect, completes the reverse address to name mapping.

/var/named/loopback-domain-info File

; Information for the loopback domain 127.in-addr.arpa.
@
IN SOA horse.zoo.edu. hostmaster.zoo.edu.
(
20060725 ; Serial number
43200 ; Refresh timer - 12 hours
3600 ; Retry timer - 1 hour
604800 ; Expire timer - 1 week
86400 ; Minimum timer - 1 day
)

IN NS horse.zoo.edu.
; Define appropriate mappings for this domain. 1.0.0 IN PTR localhost.zoo.edu.

Testing DNS Configration

Once all of your configuration files have been entered, you will want to test your DNS domain information.

The primary test tool that comes bundled with BIND is the nslookup utility. In general, nslookup is used to do the following:

BIND Debugging Tools

pkill -INT in.named  This signal causes the name daemon to take a snapshot of its in-memory cached data and write this information to the file /var/named/named_dump.db in ASCII (resource record) format. (Notice that the name daemon process stores its process ID number in the file /etc/named. pid at start-up. You can use this with the shell command substitution shown previously to send signals to the name daemon without having to know its process number or use the ps command to determine its process number.) Use the - INT argument to debug non-authoritative lookups.

pkill -USR1 in.named  This signal causes the name daemon to increase its debug level (disabled by default) by one. Each successive increase generates more debug output. You can examine the resulting output in the /var/named/named. run file. A discussion of this file is beyond the scope of this course and is discussed in DNS & BIND. The -USR argument is used to debug authoritative lookups.

pkill -USR2 in.named This signal causes the name daemon to return to debug level 0-no debug output.

pkill -HUP in.named This signal causes the name daemon to reread all of its configuration files. If you are having problems getting the name daemon to behave, it is sometimes wise to kill and restart the name daemon process rather than use the HUP signal.

You can edit the resulting file with your text editor and examine it for problems. Here is a list of typical problems you might have and how to discover them during debugging.

• Misspelled /etc/resolv.conf file name. When this is the case, the nslookup command will not give you a prompt. Any time you type nslookup and do not get a prompt, check the spelling of this file name.
• Missing trailing dot in a domain name. Depending on where you missed a trailing dot (perhaps the most common error of all in the configuration files), the symptoms can vary. A missing trailing dot at the end of an FQDN will result in the name being stored internally with the domain part of the name doubled.
   
• Check the named_dump.db file created by the pkill - INT command and look for doubled domain names for all resource records that refuse to work properly in nslookup.
  
• Incorrectly specified IP addresses for name servers in the /etc/resolv.conf file.
  When this happens the nslookup utility will not give you a prompt. Double-check the spelling of the nameserver keyword and the entering of IP addresses in the /etc/resolv. conf file.
  
• Incorrect entry of either the forward or inverse entries for the loopback domain. This is another problem that will cause nslookup to not give you a prompt. Add this to your list of items to check when nslookup "hangs."

Secondary DNS Server Setup

The contents of the /etc/named.conf file is simpler than that of the primary server. If a server is to provide both roles, a primary server for some domains and a secondary server for other domains, the /etc/named.conf file must contain keywords appropriate to both of these functions.

When you add a secondary server, it is important to coordinate with the primary server. The primary server should have an NS record for the secondary server in all files describing all domains for which the secondary will be serving. .

Testing and Debugging

You should test and debug secondary servers essentially the same as primary servers (using nslookup and pkill -INT to dump the name server's database when necessary).

DNS Security

DNS by its nature makes networks connected to the Internet vulnerable to unauthorized access. Up to BIND version 4.9, domain administrators had no way to control look-up data on their name servers. Solaris version 7 reduces the vulnerability of your network by implementing BIND version 8.x.x.

BIND version 8.x.x features are established in the configuration file /etc/named.conf. This configuration file specifies the type of server it is running on and the zones that it serves as a master, slave, or stub. It also defines security, logging, and a finer granularity of options applied to zones.

Restricting Queries

The BIND version 8.x.x allow-query statement enables you to establish an IP address-based access list on queries. This list can apply to a zone, or to any queries received by the server. The access list determines which systems are allowed to send queries to the server.

• Restricting All Queries

  Used as an argument to the options statements, allow-query imposes a restricted access list across the Internet. For example:

  options { allow-query { 128.50.1.3/24; 128.50.2.2/24; } ; };

  In this case, only systems with IP address 128.50.1.3 and 128.50.2.2 would have access to the name server.

• Restricting Queries in a Particular Zone Used as an argument to the zone statement, allow-query imposes a restricted access list to a particular zone. For example:

  zone "central.sun.com" {
  type slave;
  file "db.central";
  masters { 128.50.1.1; } ; allow-query { "zoo.edu"; } ;

  In this case, only subnet zoo.edu would have access to the name server.
  

Preventing Unauthorized Zone Transfers

• Authorizing Zone Transfer. Used as an argument to the zone statement, allow-transfer imposes a restricted access list to a particular slave server for zone transfers. For example:

  zone "central.sun.com" {
  type master;
  file "db.central";
  allow-transfer { 128.50.1.2; } ;

  In this case, only slave server 128.50.1.2 could perform zone transfers. Block All Transfers
  The BIND default access list for zone transfers is any host. If you want to block all transfers from your name server specify the allow-transfer host as "none".

  For example:

  zone "central.sun.com" {
  type master;
  file "db.central";
  allow-transfer { none; } ;

• Authorizing Global Zone Transfer. BIND will also let you establish a global access list on zone transfers. This applies to any zones that do not have their own, explicit access list defined as zone statements. The option allow-transfer limits zone transfers to only the enumerated address. For example:

  options {
  allow-transfer { 128.50.1.3/24;} ;

  In this case, only slave server 128.50.1.3 could perform zone transfers across the Internet.

Miscellaneous DNS Topics

Following are other DNS subjects to consider:

• $ Directives
DNS configuration has two special keyword directives that begin with a dollar sign ($). Both of these are optional, but you can use them to make your administrative life easier.

• $ORIGIN domain.name.
  The $ORIGIN directive resets the current origin, which is set to the value of the @ at the beginning of the SOA record by default. Recall the current origin is appended to any domain name on any resource record not ending in a dot.
• You sometimes use $ORIGIN when defining many records that refer to systems in another domain and when using $ORIGIN would save keystrokes.
  $ORIGIN can be used as many times in a file as desired.
  
• The $INCLUDE directive is used to include the text of the file specified by path-to-file at the current point in the configuration file.
  Included text occurs as if you had typed it in the file yourself at exactly the same place as the $ORIGIN with the exception that any origin set in the original file with a $ORIGIN directive does not carry over to the records from the included file.
  You can use $ INCLUDE as many times in a file as you desire.
• h2n. h2n is a Perl script that largely automates the initial setup and subsequent maintenance of DNS zones. h2n takes command-line options, reads the /etc/inet/hosts-like file and several other configuration files, and generates all of the required DNS configuration files. Updating a domain consists of editing the original /etc/inet/hosts-like file and rerunning h2n. Serial numbers are also automatically updated to keep secondary servers updating correctly. You can find h2n on the Internet by using your favorite search engine. The script that you download assumes that you have Perl loaded and running on your DNS server.
   

• DIG. DIG is a DNS debugging tool created by the developer of DNS that allows more in-depth control over debugging than the nslookup utility that comes with BIND.

DNS Resources

The following is a list of resources you can use when configuring DNS:

• info.bind newsgroup This newsgroup contains discussions about DNS and BIND and announcements of various kinds from the BIND developers and the ICANN. It is a good newsgroup to browse from time to time.
• www.internic.net. The web site of the INTERNIC contains information about how to register a domain, the official list of root servers, and various DNS procedures and policies. It is the originating repository for all RFCs.
  
• RFCs. There are many of RFCs on or related to DNS. The following list identifies a few of the more significant ones:
  • RFC 1032 - Domain Administrators Guide
  • RFC 1033 - Domain Administrators Operations Guide
  • RFC 1034 - Domain Names - Concepts and Facilities
  • RFC 1536 - Common DNS Implementation Errors and Suggested Fixes
  • RFC 1713 - Tools for DNS Debugging
  • RFC 1886 - DNS Extensions to Support IP Version 6
  • RFC 1912 - Common DNS Operational and Configuration Errors
  • RFC 2136 - Dynamic Updates in the Domain Name System (DNS UPDATE)

Cuddletech's BIND Cheat Sheet

Source can be found at: http://www.isc.org/products/BIND/

Files of interest:
	-/etc/named.conf	BINDs central configuration file
	-/var/named		Directory containing maps
	 -db.cache		Root Server Referance
	 -db.<domain>		Host Listings, Aliases, etc.
	 -db.XX.XX.XX		Reverse Maps
	 -db.127.0.0		Local Domain Reverse Map


*********************************************************************************
DB Files:
---------

 You'll have several DB files.  The first is the name-to-address
mapping.  Typically this file is named "db.<domain>".  The second
DB file you'll have is the address-to-name mapping, typically
contained in a file named "db.xx.xx.xx" (eg: db.10.1.0).  These
maps are also commonly called "reverse maps".  While there is 
generally only one name-to-address map, there should be one
reverse map per network.  The last map will be the loopback
map, named "db.127.0.0", which obviously is also a reverse map.

 Note that the headers are: zone, class, type, nameserver, admin mail.
This is important.  The address here "ns.cuddletech.com." is 
the name of the primary master for "this data".  The second is
the email address for the DNS admin, with a "." in place of an "@".
The mail address is not used by the daemon and is only for human
consumption.

DB File Record Types:
	SOA	Indicates authority for this zone data
	NS 	List a name server for this zone
	MX	Mail Exchanger
	A	Name-to-Address mapping
	PTR	Address-to-Name mapping
	CNAME	Canonical name (aliases)
	IN	INternet Class (optional)
	RP	Responsable Person
	TXT	Text Field

Example of name-to-address map	   	    (File: db.cuddletech)
-----------------------------------------------------------------
cuddletech.com. IN SOA ns.cuddletech.com. root.ns.cuddletech.com. (
                                4        ; Serial
                                10800    ; Refresh
                                3600     ; Retry
                                604800   ; Expire
                                86400 )   ; Minimum TTL

; Name Servers

cuddletech.com.                 IN NS   ns.cuddletech.com.

; Host Addresses

localhost.cuddletech.com.       IN A    127.0.0.1
ns.cuddletech.com.              IN A    10.0.0.1
pris.cuddletech.com.            IN A    10.0.0.2
deckard.cuddletech.com.         IN A    10.0.0.3

; Aliases....

nexus.cuddletech.com.           IN CNAME ns.cuddletech.com.
nexus6.cuddletech.com.          IN CNAME ns.cuddletech.com.
intraweb.cuddletech.com.        IN CNAME deckard.cuddletech.com.
-----------------------------------------------------------------


Example of address-to-name (reverse) map        (File: db.10.0.0)
-----------------------------------------------------------------
0.0.10.in-addr.arpa. IN SOA ns.cuddletech.com. root.ns.cuddletech.com. (
                                4        ; Serial
                                10800    ; Refresh
                                3600     ; Retry
                                604800   ; Expire
                                86400 )   ; Minimum TTL

; Name Servers

0.0.10.in-addr.arpa.    IN NS   ns.cuddletech.com.

; Canonical Names

1.0.0.10.in-addr.arpa.  IN PTR  ns.cuddletch.com.
2.0.0.10.in-addr.arpa.  IN PTR  pris.cuddletech.com.
3.0.0.10.in-addr.arpa.  IN PTR  deckard.cuddletech.com.
-----------------------------------------------------------------


Example of loopback map			       (File: db.127.0.0)	
-----------------------------------------------------------------
0.0.127.in-addr.arpa. IN SOA ns.cuddletch.com. root.ns.cuddletech.com. (
                                4        ; Serial
                                10800    ; Refresh
                                3600     ; Retry
                                604800   ; Expire
                                86400 )   ; Minimum TTL

0.0.127.in-addr.arpa.           IN NS   ns.cuddletech.com.

1.0.0.127.in-addr.arpa.         IN PTR  localhost.
-----------------------------------------------------------------

NOTE: Here are some tricks...
 - You can add a "@" before your SOA entry and shorten things a bit,
   excluding the zone name, and modifing entries like this:
   The record: ns.cuddletech.com.              IN A    10.0.0.1
   Becomes:    ns		 	       IN A    10.0.0.1
   Or this: 0.0.10.in-addr.arpa.    IN NS   ns.cuddletech.com.
   Becomes: 			    IN NS   ns.cuddletech.com.
   Or this: 2.0.0.10.in-addr.arpa.  IN PTR  pris.cuddletch.com.
   Becomes: 2			    IN PRT  pris.cuddletch.com.
   And this: intraweb.cuddletech.com.        IN CNAME deckard.cuddletech.com.
   Becomes:  intraweb			     IN CNAME deckard 
  
 - You can omit the class in all records, the "IN". INternet Class is assumed.
 - Leaving the record name blank implies the last record name, repeated.  In
   our previous examples, @ was being interpreted as the zone name, and in
   our example we listed the NS entry as having no entry name.  That's because
   @ would be expanded to "0.0.10.in-addr.arpa.", and the first record is
   our NS entries, who's records would be named "0.0.10.in-addr.arpa."...
   a repeat.  This is why they can be omitted.  This same principle is avalible 
   throughout the db files.
 - The MX type, is for mail routing.  Use this to point to your MTA.  Syntax is:
	(domain)	     (priority)        (MTA)	
	cuddletech.com.	IN MX	1	mailhub.cuddletech.com.	
 - The RP and TXT types work together.  Their syntax is:
	(host) 		(email addr)		(record)
	ns	IN RP	root.cuddletech.com. system.cuddletech.com.
	system	IN TXT 	"This is an administrative system"
	
*********************************************************************************
The Root Cache DB File:

 The special map thats the same everywhere (almost) is the
root cache db (typically named: db.cache).  This file is
obtained from interNIC's ftp server, and contains the data
needed to access/reference the root servers.
 The map can be obtained at:
ftp://FTP.RS.INTERNIC.NET/domain/named.root


*********************************************************************************
The BIND Configuration File:

 The BIND configuration file is named /etc/named.conf.  If it's named
/etc/named.boot your on a system loaded with BIND 4.x.  Some systems
will an "in" between the zone and "{", this denotes class, INternet 
class.  The "in" (in all cases) is assumed and can be removed.  Note
that the MINIMUM number of zones anyone will have is FOUR.



Example of BIND's config file		  (file: /etc/named.conf)	
-----------------------------------------------------------------
options {
        directory "/var/named";
};

zone "." {
        type hint;
        file "db.cache";
};

zone "0.0.127.in-addr.arpa" {
        type master;
        file "db.127.0.0";
};

zone "0.0.10.in-addr.arpa" {
        type master;
        file "db.10.0.0";
};

zone "cuddletech.com" {
        type master;
        file "db.cuddletech";
};
-----------------------------------------------------------------


*********************************************************************************
Setting up a SLAVE Server:

 Slave servers are even easier.  If BIND is already installed
 on the server, here are the steps:

 1) Copy "named.conf" from the master server to the slave.

 2) Create a directory for the databases, according the
	the config files "directory" directive.
 
 3) Copy the local-reverse map (db.127.0.0) and the root cache (db.cache)
	files into the slaves database directory.

 4) Edit "named.conf", changing the map names from "type master;", to
	"type slave;", for all zones with the exceptions of the root
	cache and the local-reverse map. 

 5) Still editing "named.conf", add a "masters" directive to all the
	slave zones, in the form: "masters { XX.XX.XX.XX; };"

 6) Start the server like normal.


Example of a Slave BIND config file       (file: /etc/named.conf)
-----------------------------------------------------------------
options {
        directory "/var/named";
};

zone "." {
        type hint;
        file "db.cache";
};

zone "0.0.127.in-addr.arpa" {
        type master;
        file "db.127.0.0";
};

zone "0.0.10.in-addr.arpa" {
        type slave;
        file "db.10.0.0";
	masters { 10.0.0.1; };
};

zone "cuddletech.com" {
        type slave;
        file "db.cuddletech";
	masters { 10.0.0.1; };
};
-----------------------------------------------------------------

*********************************************************************************
BIND Signal Handling:						 (process: named)

	Signal		Action
	------		-------------------------------------------------------------
	HUP		Reload the name server.  Master reloads. Slaves pull new maps.
	INT		Dump the internal database to <directory>/named_dump.db
	ILL		Append name server stats to named.stats in name servers cwd
	USR1		Append debuging info to named.run in name servers cwd
	USR2		Turn off debugging.
	WINCH		Toggle logging all queries to syslog
	TERM		Exit and save dynamic zones to files.

*********************************************************************************
Building BIND from Source

 This is a simple process.  Grab the source from ftp.isc.org/isc/bind/src/cur/bind-8/
Then unpack, change into that directory and:
 1) make stdlinks
 2) make clean
 3) make depend
 4) make
 5) make install

*********************************************************************************
The complete, and thorough Resource Record (RR) syntax reference:

- A address
	(owner) (class) (ttl) A (address)
	Example: localhost.cuddletech.com. IN A 127.0.0.1
	Where: address is a 32bit address
- CNAME canonical name
 	(owner) (class) (ttl) CNAME (canonical-dname)
	Example: yummy IN CNAME icecream.cuddletech.com.
	Where: owner is the alias, and cname is the real name
- HINFO host information
	(owner) (class) (ttl) HINFO (cpu) (os)
	Example: system.cuddletech.com. IN HINFO Sun4500 Solaris
	Where: cpu is a string specifing the cpu and os is a string
		specifying the os.
- MB mailbox domain name - experimental
	(owner) (class) (ttl) MB (mbox-dname)
	Example: root.cuddletech.com. IN MB ns.cuddletech.com.
	Where: mbox is a domain-name which specifies a host with the
		specified mailbox.
- MD mail destination - obsolete
	Replaced with MX
- MF mail forwarder - obsolete
	Replaced with MX
- MG mail group member - experimental
	(owner) (class) (ttl) MG (mgroup-dname)
	Example: admin.cuddletech.com. IN MG root.cuddletech.com
					IN MG oracle.cuddletech.com
	Where: owner is the address, and mgroup is the "subscribers"	
- MX mail exchanger
	(owner) (class) (ttl) MX (preference) (exchange-dname)
	Example: cuddletech.com. IN MX 0 mts.cuddletech.com.
	Where: owner is the domain, preference is the order in	
		which mx records should be used, and exchange
		is the name of the mail server.
- NS name server
	(owner) (class) (ttl) NS (name-server-dname)
	Example: cuddletech.com. IN NS ns.cuddletech.com.
	Where: dname is the dns server, and owner is the domain
- PTR pointer
	(owner) (class) (ttl) PTR (dname)
	Example: 1.100.164.192.in-addr.arpa. IN PTR system.cuddletech.com.
	Where: dname is the dns name, and owner is the reversed address
- SOA start of authority
	(owner) (class) (ttl) SOA (source-dname) (mbox) "("
		serial refresh retry expire minimum ")"
	Example: cuddletech.com. IN SOA ns.cuddletech.com. root.ns.cuddletech.com (
			1; 10800; 3600; 604800; 86400 )
	Where: owner is the name of the zone, source-dname is the name 
		of the primary name server, and where mbox is the mailbox
		responsible for this domain
- TXT text
	(owner) (class) (ttl) TXT (text-string)
	Example: newsys.cuddletech.com. IN TXT "Location: Under the Desk"
	Where: owner is the owner is the system and txt-string
		is the description
- WKS well-known service
	(owner) (class) (ttl) WKS (address) (protocol) (service-list)
	Example: server.cuddletech.com. IN WKS 10.0.0.5 TCP ( telnet ssh ftp domain ) 
	Where: owner is the machine name, address is a 32bit address, protical
		is the protical name, and service list is the services to direct.


--------------------
Useful Links:
The DNS Resource Directory: http://www.dns.net/dnsrd/
DNS Boss Config App: http://www.dnsboss.com/
DNS Documentation: http://www.isc.org/products/BIND/bind8.html
Interesting Tools: http://www.domtools.com/

########################DAS ENDE####################################################
########Created for & by: [email protected]#######################################
###################################################################\(^_^)/##########

Etc

Society

Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers :   Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism  : The Iron Law of Oligarchy : Libertarian Philosophy

Quotes

War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda  : SE quotes : Language Design and Programming Quotes : Random IT-related quotes :  Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce :  Bernard Shaw : Mark Twain Quotes

Bulletin:

Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 :  Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method  : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law

History:

Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds  : Larry Wall  : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS :  Programming Languages History : PL/1 : Simula 67 : C : History of GCC development :  Scripting Languages : Perl history   : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history

Classic books:

The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month :  How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite

Most popular humor pages:

Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor

The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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Last modified: March, 12, 2019