Hi Tobias,
Now the zone is signed with two ZSKs. How can I get rid
of the old ZSK?
In simple DNSSEC terms, the idea of a rollover, regardless if it was
for ZSK, KSK or even an algorithm rollover, is that old settings appear
in the same zone that will have new settings. This is to help validating
resolvers to still use old (cached) RRSigs or DS records and respond to
them, as well as caching new ones, until old ones expire. If you remove
old RRSigs without giving time for resolvers to cache new details, then
resolvers will fail to accept new zone details, even if they are being
signed by the intended zone master signer. This is more properly
explained in RFC7583 <https://tools.ietf.org/html/rfc7583>.
Now, how long it takes for a 'rolled over' item to remain in your zone,
this is what you should be able to define in your policy settings. I
can't comment on how Knot does it because we don't use it do DNSSEC
management, but it's a slave to our master signer so all our zones
served by Knot are DNSSEC secured.
HTH,
Kareem.
--
Abdulkareem H. Ali
Network Operations Engineer
CentralNic Group PLC
London Stock Exchange Symbol: CNIC
+44 20 3388 0600
www.CentralNic.com
CentralNic Group PLC is a company registered in England and Wales with
company number 8576358. Registered Offices: 35-39 Moorgate, London, EC2R
6AR.