At 02:50 2004-08-03 -0700, Jeff Chan wrote:
I think that would be done by lowering the TTL. The time to live appears to indicated to DNS how quickly new information should be served up. Do any DNS gurus know if that's correct? In other words if we lower the TTLs on our zone files should we expect new entries to be visible sooner.
If you are using version 9 of Bind, the positive TTL is set by the $TTL directive for the zone, unless there is a specific TTL for the RR, in which case that is used.
Negative TTLs (for NXDOMAIN/"not found" replies) are set by the "minimum" SOA directive.
This "negative caching time" use of the miminum directive is specific to Bind 9 though. Earlier versions of Bind and most other name servers treat it as a default miminum TTL in general.
For rbldnsd, it might be possible to do something similar using the soa ttl value for negative and the $ttl directive for positive replies, but I am not sure.
Finally, has any progress been made speeding up the refresh times for multi.surbl.org?
It's certainly something that can be done rather easily but I'd like to get some feedback about the impact on our nameservers as a result. Do shorter TTLs mean more DNS traffic? Does it cause positive caches to expire sooner and therefore cause more querying of authoritative name servers?
At least in theory, with Bind 9, negative and positive caching can be set separately.
Try lowering the 8H 'minimum' value for multi.surbl.org while keeping the 8H RR TTL or zone $TTL value.
Patrik