HELP! [long]

Re: HELP! [long]

From:

Date:

Time:

>Chris Buxton wrote:
>>
>> >I would like some information on this QuickDNS Pro. After installing and
>> >opening the program. Just what are you suppose to do anyway?
>>
>> That depends on what you're trying to do, and what your DNS background is.
>>
>> If all you want is DNS resolution, just start it up and set MacTCP or
>> TCP/IP to use it for name resolution.
>>
>> If you're trying to set up a domain zone file, and are used to BIND on a
>> Un*x platform, then, for the most part, it will work very similarly. Create
>> your zone file in QuickDNS Admin, with one record per line. The exception
>> is the SOA record - it gets split up into parts in one of the menu items
>> (Get Info, or Domain Info, or something). The named.boot file doesn't
>> exist; instead, all primary zone files should go into the Primary Domains
>> folder, and all secondary domains should be listed in the Secondary Domains
>> file. (I may have some names wrong.)
>>
>> If you're new to DNS, and need to set up a domain name, see
>> <http://www.pism.com> for some good information.
>>
>My DNS Background is zip. What do you mean go into TCP/IP and set it for
>QUICK DNS. Well, I guess tomorrow I open TCP/IP and see what is there.
>As far as reading <http://www.pism.com> I think I have read it about 10
>times now and find it to be as clear as mud.

[snip]

As I recall from when I first learned DNS, it's hard to grok (get the hang
of), but easy once you've got it.

I learned it by reading the entire book "DNS and BIND", from O'Reilley and
Associates, a Unix handbook. It took me a day to go from novice to
competency. However, I learn best by reading manuals - YMMV.

What follows is my attempt to describe the whole thing using as little
technical jargon as possible, and defining what technical jargon is needed.
I hope it helps.

------------------------------------------------------------------------

There are 4 basic questions an Internet app might need answered: What
address does a name correspond to, what name does an address correspond to,
what server handles mail for a given name, and what server is responsible
for answering the above questions.

All these questions are answered by name servers. However, they require
some research, and most non-Unix computers don't know how to do this
research. Therefore, they are told to pose all questions to a researcher,
called a name resolver. The name resolver starts asking around until it
finds the answers.

QuickDNS Pro, like most DNS servers, does both jobs - it acts as name
server for your domains, and acts as name resolver for any computer that
has been instructed to ask it. [QuickDNS Lite is different: It offers name
resolution only.]

To use QuickDNS Pro for a name resolver for a Mac workstation, open up the
TCP/IP control panel and enter the numeric address of the server in the box
marked "Name server addr:". On older Macs with older versions of the OS,
this setting goes in MacTCP.

For setting up name service, you need to understand how DNS records and
zone files work. There are two types of zone files: domain zones and
reverse zones. A domain zone file contains all information about a given
domain name, with the possible exception of any delegated subdomains.

Example: "com" is a domain name, and "apple.com" is a delegated subdomain
of "com". It's delegated because Internic, which is responsible for the
"com" domain, lets Apple manage the "apple.com" subdomain, meaning it's
handled by a different server from the "com" domain. Similarly,
"info.apple.com" is a delegated subdomain of "apple.com", and is handled by
a different server from "apple.com". Subdomains can be handled by the same
server as the parent domain, making them undelegated subdomains.

The other type of zone is the reverse zone. This works very similarly to
domain zones, but its purpose is to provide a way to match names to
addresses, instead of the other way around. If a program needs to know the
name that goes with "206.79.218.54", the name resolver it asks won't query
every domain zone until it happens across it; instead, it will ask the root
servers for the name of the server responsible for that reverse zone. The
strange thing is the actual question it asks: It asks for the name
associated with "54.218.79.206.in-addr.arpa". Notice the numbers have been
turned around. That's just how reverse zones work.

Each zone file is organized into lines, or records. Each record fits on a
line, with one exception, and only one record can occupy a given line. The
exception to the one line per record rule is the Start of Authority, or
SOA, record. QuickDNS Pro Admin puts the SOA record in a special menu item,
Get Info (in the Domain menu). This is the only record that has so many
parts, so it gets handled separately.

For all other records, there are basically 3 parts: The name for which the
record provides information, the type of information provided (the record
type), and the information itself. So, for instance, to assign an address
to a particular name, the record looks like:

www.apple.com a 17.0.0.1

The first part is the name to which this address is being applied, the
second part is an abbreviation of the record type (Address), and the third
is the actual address.

Here's a description of the 5 most important record types:

A Address Assigns an IP address to the given name.

PTR Pointer Assigns a name to the given IP address.

SOA Start of Authority Declares that this server is responsible for
this zone file. Defines such durations as how
long info on this domain should be cached
before
a fresh copy is needed from the authoritative
server.

NS Name Server Assigns a name server to be responsible for the
given zone.

MX Mail Exchange Assigns a mail server to be responsible for
mail
for the given domain zone. It has one extra
piece of information, a priority number. The
lowest priority server listed is considered
the final destination of mail for the domain.
Any other servers listed are considered
accpetable alternatives to the outside
world, in
the event that the lowest numbered server is
unavailable.

Each record in a zone file (other than the SOA record) must start with a
name that belongs to the domain specified at the start of the SOA record.
Therefore, you can never put A records and PTR records in the same zone
file, since PTR records start with a reversed IP address, in the form of
xxx.xxx.xxx.xxx.in-addr.arpa, whereas A records always start with names
that belong to a domain that ends in "com", "org", "edu", "mil", "gov",
"net", or a country code.

Every zone file has an SOA record. For reasons I won't go into, every zone
file needs at least two NS records for itself, and one NS record must point
to the server that hosts the zone file. (All other servers pointed to by an
NS record must also have a copy of this zone file.)

So, a domain zone file must have an SOA record and at least 2 NS records,
and usually will have at least one A record and at least one MX record.

A reverse zone file must have an SOA record and at least 2 NS records, and
usually will have at least one PTR record.

There are other record types. Some are obsolete, some are only there for
the edification of anyone reading the zone file.

-------------------------------
Chris Buxton
Independent Consultant
Specializing in Web Development

Sales:
888/4-DPOINT

Support:
858/452-3696