Primary DNS failover

Cricket Liu cricket at acmebw.com
Tue Apr 11 20:43:19 UTC 2000


> On Thu, Mar 02, 2000 at 05:18:34PM -0800, Michael Voight wrote:
> > Microsoft uses multimaster. (I think that's the name)
> > Obviously, not being standards based, you can't mix it with a UNIX
> > primary for the same domain. 
> 
> Over the last month, this has been mentioned numerous times by two
> people, with no explanation of what it is.  Michael, what is this
> "multimaster" capability?  What does it provide over and above the BIND
> capability of multiple equivalent name servers that are "failed over"
> to automatically when any are down?  If it distributes the database of
> a SINGLE domain over multiple servers, how does it avoid requiring
> searching ALL servers before declaring that a given name does or does
> not exist, and all the other problems that have been mentioned before?

The Microsoft DNS Server in Windows 2000 supports a feature called
"Active Directory integrated zones."  With AD-integrated zones, zone
data is actually stored in Active Directory and is replicated between
authoritative name servers using AD's replication mechanism, not
traditional zone transfers.  Therefore, with AD-integrated zones, all
the authoritative name servers for the zones run as primary masters,
and all can accept dynamic updates to the zones.

For example, say you've got two authoritative name servers for
zone foo.com, a.foo.com and b.foo.com.  If a.foo.com gets a
dynamic update to foo.com, it processes it and AD replication
syncs b.foo.com's copy of foo.com.  If b.foo.com gets a
dynamic update to foo.com, it processes it and AD replication
syncs a.foo.com's copy of foo.com.

The advantage to this, according to Microsoft, is that one of
your authoritative name servers can fail, and you can continue
to process dynamic updates.

cricket

Acme Byte & Wire
cricket at acmebw.com
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