On Monday, October 18, 2004, 19:11:38, Len Conrad wrote: >>> 12 hours. >> >>plus Refresh interval if the slaves don't support NOTIFY. > > slaves don't respect TTL (used for caching only), because they are > authoritative for the zone, so don't cache the records.
Precisely so when they return a record its the full 12 hour TTL. >>Assume a 4 hour Refresh interval >>- slave makes a SOA query and finds it has the latest serial number >>- you change your master >>- 3.99+ hours later someone queries the slave and receives and caches >> the old IP with a 12 hour TTL >>- 11.99+ hours later that IP is still in the cache > > Theoretically correct, but BIND and W2K DNs both send notify to all NS > records by default, so in practice, you're splitting frog hairs worrying > about slave latency. I'm a pessimistic paranoid :-) -- [EMAIL PROTECTED] "The avalanche has already started, it is too Rod Dorman late for the pebbles to vote." � Ambassador Kosh To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
