Configuration of bind8

Barry Margolin barmar at
Fri Mar 10 22:09:47 UTC 2000

In article <F2413A849CC9D211AC3500805FFE3E970992BF at>,
Evans, Lorne R ISTA:EX <Lorne.Evans at> wrote:
>	After successfully running W2K DDNS as master - I setup BIND
> to be the master instead for the W2K zones.  I blindly specified
>the W2K defaults for the SOA  as per the attached - but get the following
>BIND messages.  Given the default TTL for the dynamic W2K SRV records
>appears to be 10 minutes - are there any rules of thumb for determining
>optimal BIND SOA values for the expire, retry, and refresh values?  I found
>Jim's recommedation for expire - but - came up empty for retry and refresh?
>	Thanks - and - attached....
>master zone "" (IN) loaded (serial 2000030615)
> WARNING SOA expire value is less than 7 days (86400)
> WARNING SOA refresh value is less than 2 * retry (900 < 600
> 2)

It depends on how quickly you need DNS changes to propagate.  If you reduce
the refresh time, slave servers will check for changes on the master more
often.  But this also means more load on the masters and slaves, since they
perform these checks more often, and that takes time away from serving
ordinary queries.  Unless you're hosting thousands of domains this probably
isn't significant, though.

If all your slave servers support the NOTIFY protocol (BIND 8 and Microsoft
DNS support it) then refresh time isn't too important.  When the domain is
changed, the master will notify the slaves, and they'll perform a zone
transfer within a few minutes.

Barry Margolin, barmar at
GTE Internetworking, Powered by BBN, Burlington, MA
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

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