Dave Warren skrev den 2018-02-06 20:39:
How low are the TTLs? I'm seeing 300 seconds on 127.0.0.2 which is
more than sufficient time for a single message to finish processing,
such that multiple queries from one message would absolutely be cached
(or more likely, the first would still be pending and the second would
get the same answer as the first).
first query would be valid for 300 secs, but that is imho still not
free, problem is that keeping low ttls does not change how dns works,
any auth dns servers will upate on soa serial anyway, the crime comes in
when sa using remote dns servers that ignore soa serial updates
in that case ttls would keep spammers listed for 300 secs only
and thats why i say 300 secs helps spammers
;; ANSWER SECTION:
2.0.0.127.bb.barracudacentral.org. 300 IN A 127.0.0.2
Maybe the TTLs are different for other records?
300 is imho to low to anything thats called free
i would like to accept free if it was 3600
I am also noticing very intermittent response times, sometimes taking
over a second to get a response, other times taking under 50ms.
rndc querylog is my friend
i just like to start a debate on why 300 is accepted as free, it does
matter for non datafeeds users, but for datafeeds it does not matter at
all
