Differences between version 6 and previous revision of SOA.
Other diffs: Previous Major Revision, Previous Author, or view the Annotated Edit History
| Newer page: | version 6 | Last edited on Wednesday, November 24, 2004 4:20:57 pm | by MikeBeattie | Revert |
| Older page: | version 5 | Last edited on Wednesday, November 24, 2004 4:02:19 pm | by MikeBeattie | Revert |
@@ -16,28 +16,28 @@
</pre>
The format of a [SOA] [RR] is "<tt>name <ttl> class rr name-server email-address (serial refresh retry expire negttl)</tt>"
-The name is given as "<tt>@</tt>", since that is the shorthand for the value of <tt>$ORIGIN</tt>. [TTL] is missing from this example, as it takes the zone default defined above as <tt>$TTL</tt>. The class will usually always be IN, [RR] should be obvious :). The name-server field is bascally the [FQDN] of the primary NameServer
for the domain (don't forget the trailing '.'!). The email-address field is the address of the person responsible for the domain - the first dot should be read as an <tt>@</tt>, so above should be read as <tt>root@ethernal.tla</tt>.
+The name is given as "<tt>@</tt>", since that is the shorthand for the value of <tt>$ORIGIN</tt>. [TTL] is missing from this example, as it takes the zone default defined above as <tt>$TTL</tt>. The class will usually always be IN, [RR] should be obvious :). The name-server field is bascally the [FQDN] of the PrimaryNameServer
for the domain (don't forget the trailing '.'!). The email-address field is the address of the person responsible for the domain - the first dot should be read as an <tt>@</tt>, so above should be read as <tt>root@ethernal.tla</tt>.
The values in parenthesis are described below:
Serial number
Generally given in YYYYMMDDXX format, giving 100 possible revisions of any given zone in a day (Usually more than enough).
Refresh
- Defines the number of seconds before a slave [DNS] server
will refresh its copy of the zone.
+ Defines the number of seconds before a SecondaryNameServer
will refresh its copy of the zone by requesting a ZoneTransfer from the PrimaryNameServer
.
Retry
- Defines the number of seconds for a slave [DNS] server
to wait before retrying a zone refresh, after a failure.
+ Defines the number of seconds for a SecondaryNameServer
to wait before retrying a zone refresh, after a failure.
Expire
- Defines the number of seconds for a slave [DNS] server
to keep zone records, and answer authoritatively with them if it can't contact the master server
. (so, if the above Refresh
fails, and it's been Retrying
for this long).
+ Defines the number of seconds for a SecondaryNameServer
to keep zone records, and answer authoritatively with them if it can't contact the PrimaryNameServer
. (so, if the above refresh
fails, and it's been retrying
for this long).
Neg TTL
- Defines the number of seconds that a client should remember that a Negative
response was received from this server. So, if a remote server asks us what the address for <tt>foo.ethernal.tla</tt> is,
but it doesn't exist, it won't ask again
for this many seconds and use the response it got last time
, even if we add that name to the zone 5 minutes
later.
+ Defines the number of seconds that a client should remember that a negative
response was received from this server. So, if a remote server asks us what the address for <tt>foo.ethernal.tla</tt> is but it doesn't exist, it will cache the negative answer we gave it
for this many seconds, even if we add that name to the zone a couple of seconds
later.
----
Todo:
* Someone should explain TTLs a bit better, especially the use of <tt>$TTL</tt>
----
CategoryDns
