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MacDNS
Overview
Need to know more about DNS?
If you don't already understand the function of
Domain Name Service and basically how it works,
it's important to go through the
DNS
primer. It doesn't cover everything about DNS
(there are whole books written on the subject), but
it will give you enough information so that the
rest of this training module will make sense.
MacDNS Product Description
MacDNS is a Mac OS-based DNS
name server. It is ideal for serving a small- to
medium-sized site connected to the Internet. Once
youíve installed and set up the MacDNS
program, MacDNS can handle DNS queries about a
particular host (i.e., computer) at your site, find
information about that host, and send the
information back to the requester.
One clear advantage of
running MacDNS is that it reduces the amount of
outward-bound network traffic on your local-area
network (LAN). (This is especially advantageous if
you have a relatively slow connection to your ISP's
site.) Lookups for a given host name can be
serviced very quickly from MacDNSís cache.
Another advantage is that you have greater control
of your domains. For example, you can add or remove
hosts instantly, instead of waiting for a service
provider to accommodate your
request.
MacDNS offers the following
features:
- MacDNS acts as a primary
DNS server. It exports its zone information,
allowing another DNS server to provide secondary
name service. MacDNS currently does not act as a
secondary server, i.e., it does not import zone
information from another DNS server. However,
you can use MacDNS as a secondary server by
manually copying your zone file(s) from your
primary DNS server to a MacDNS
server.
- MacDNS has an easy-to-use
interface, making it straightforward to assign
domain names and IP addresses for a host. It is
also simple to create host "aliases" (multiple
names which map to the same IP address) and to
set up mail exchanger information (information
on which host(s) provide mail service).
- MacDNS automatically
maintains address-to-name mappings for all hosts
in a zone.
- MacDNS supports both
standard and reverse queries
(name-to-IP-address, IP-address-to-name). The
following resource record types are
supported:
- A
(address)
- PTR
(pointer)
- MX (mail
exchanger)
- NS (name
server)
- HINFO (machine
info)
- SOA (start of
authority)
- CNAME (canonical name,
or alias)
- MacDNS imports and
exports data files in standard zone format. This
means that existing host entries from UNIX-based
DNS servers can be imported into MacDNS (See the
"Technical Assistance" page for one
caveat on
importing data from Unix DNS
hosts).
- Multiple domains can be
served simultaneously.
- MacDNS can share the load
for a given named host between several machines.
It does this by grouping a number of hosts under
a single "load-shared" name. For each successive
query, MacDNS returns the address of a different
host in the load-shared group. This has the
effect of spreading successive connections
across all the hosts in a round-robin fashion.
It is also possible to temporarily disable one
or more hosts in the group while the others
continue to service client
requests.
- MacDNS will cache
information for hosts on the Internet. This
capability decreases network traffic on the
connection to the Internet (which is often
slower than the local-area network) and gives
faster responses to these queries.
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Distribution and Availability
MacDNS is available in three ways (not all of
which include telephone support):
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System Requirements
MacDNS 1.0.4 requires the
following minimum system
configuration:
- A Macintosh computer with
at least a 68020 processor, or a PowerPC
processor
- 1500K of free
memory
- A TCP/IP network
connection and static IP address
- System 7.0 or later
(System 7.5.3 recommended)
- MacTCP 2.0.6, or Open
Transport 1.1 or later
NOTES:
- If you are running a
system version prior to 7.5, you also need to
install the Thread Manager 2.0.1 extension
(available at Apple Software
Updates).
- Open Transport networking
software, version 1.1 or later, is recommended
for use with MacDNS. (System 7.5.3 includes Open
Transport version 1.1.)
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