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<TITLE>DNS record types</TITLE>
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<i>This document has been placed in the public domain by Sam
Trenholme</i>
<H1>DNS record types</H1>
This is a list of some DNS record types which MaraDNS supports.
<DL>
<DT>A
<DD>A, or address, records describe the IP that a given DNS node has.
<p> MaraDNS
uses the A character to signify an A record. This has one
data-dependent field: The ip
for the node in question, in dotted decimal (e.g. 192.168.42.55) format.
<DT>MX
<DD>MX, or mail exchange, records describe the machines to contact in
order to send mail to a given DNS node.
<p>
MaraDNS uses the @ character to signify an MX record. This has two
data-dependent fields:
The
preference for the mail exchanger (lower preferences get higher priority),
and the name of the DNS node to deliver mail to.
<DT>NS
<DD>NS, or name server, records are used to tell other DNS servers which
DNS servers to contact in order to find out information for a given DNS
node. For example, a NS record for example.com tells other DNS servers
which DNS servers to contact in order to obtain information for the
example.com domain. Because of the way MaraDNS is set up, all of the NS
records for a given DNS zone need to be placed immediately after the SOA
record.
<p>
MaraDNS uses the N character to signify an NS record. This has one
data-dependent field:
The name of the DNS node which this NS record points to.
<DT>SOA
<DD>SOA, or "start of authority", records are used by other DNS servers,
and, unfortunatly, are therefore required by MaraDNS. Each zone file
<i>must</i> start with an SOA record.
<p>
MaraDNS uses the S character to signify an SOA record. A SOA record
has seven data-dependent fields, as follows:
<UL>
<LI>The first field needs to be the name of the DNS zone in question
<LI>The second field should ideally be an email address. Just use
nobody@example.com
<LI>The third field, which is numeric, is called the "serial" for the
zone in question. In the case of MaraDNS being a "primary zone server"
for another DNS server, this number needs to be incremented every time the
zone file is changed. Otherwise, just give this a value of 1.
<LI>The fourth field, also numeric, is the "refresh" of a zone. Just
make this 7200 (two hours).
<LI>The fifth field is the "retry" of a zone. Just make this 3600 (one
hour).
<LI>The sixth field is the "expire" for a zone. Just make this some
really bug number, like 4838400 (eight weeks).
<LI>The seventh field is the "minimum" for a given zone.
Some
caching DNS servers use this number to determine how long to remeber that
a given DNS node does not exist, and "secondary zone servers" also use
this number. It is safe to give this the same value as the TTL for the
SOA record (For example, 86400 seconds: one day).
</UL>
In most cases, MaraDNS zone files can start with this particular SOA
record:
<PRE>
S%|86400|%|nobody@example.com.|19770616|7200|3600|4838400|1800
</PRE>
<DT>TXT
<DD>TXT, or text, records are arbitrary text strings (up to 255 characters
long) which can be attached to given DNS nodes. Useful for using DNS to
make public notes available, such as "My goodness, someone is actually
reading a DNS TXT record".
<p>
MaraDNS uses the T character to signify a TXT record. This has one
data-dependent record: The text string in question.
</DL>
Note that this document does not describe every single record type that
MaraDNS support. Please refer to the <A href=man.csv1.html>CSV1 manual
page</A> for a more complete reference.
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