> What do you think recommended values are ? I know have for everything > in 193.in-addr.arpa: > > @ IN SOA ns.ripe.net. hostmaster.ripe.net. > ( > 1.20 ; Serial > 14400 ; Refresh 4 hours > 3600 ; Retry 1 hours > 604800 ; Expire 7 days > 518400 ; TTL 6 days > ) > > which in my view is reasonable, since these things (just delegations) > do not change too often. For the actual class C zones, we have for > 45.87.192.in-addr.arpa (RIPE NCC net): > > @ IN SOA ns.ripe.net. hostmaster.ripe.net. > ( > 1.4 ; Serial > 28800 ; Refresh 8 hours > 7200 ; Retry 2 hours > 604800 ; Expire 7 days > 86400 ; Minimum 1 day > ) > > Are these fine to be recommended ? > > -Marten > I think the following could be reasonable values and rules to recommended. Refresh and retry have a direct impact on how much ns.ripe.net will have to do when acting as secondary for delegated 256-Cblocks. Maybe Piet Berteema has something more to say on this subject. For the real name of the sender see the From: line... ;-) ( yymmddv ; Serial 28800 ; Refresh 8 hours 3600 ; Retry 1 hour 604800 ; Expire 7 days 172800 ; Default TTL 2 days ) where yyddmmv is the recommended way to hold the update serial number - Serial: I can't recommend a specific format for the Serial, since what people choose for it depends amongst other things on the means they use to maintain the zone file. As long as: - the Serial is incremented with each change, - the Serial doesn't become too large (after conversion to an integer when maintained in dotted decimal notation) so it becomes negative on queries and on secondaries, it's all fine with me. - Refresh: 8 hours is fine with me; for 193.in-addr.arpa itself 1 day would even be enough. - Retry: could be 2 hours, to be brought down in case of lousy connectivity, but I'd say not less than 30 mins. - Expire: 7 days is fine, but for 193.in-addr.arpa I'd suggest to raise it to 30 days. - Default TTL: depends on how frequent the expected changes are; anywhere between 1 day ("subdomain") and 7 days (193.in-addr) should be fine. Piet