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PowerDNS / pdns

PowerDNS Authoritative, PowerDNS Recursor, dnsdist
https://www.powerdns.com/
GNU General Public License v2.0
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inbound IXFR to bindbackend quietly fails #7255

Open paddg opened 5 years ago

paddg commented 5 years ago

Short description

I tried to slave a zone in Bind backend via IXFR. The documentation suggests it works: https://doc.powerdns.com/authoritative/domainmetadata.html#ixfr https://doc.powerdns.com/authoritative/modes-of-operation.html#ixfr-incremental-zone-transfers

But it does not work. pdnsserver claims Done with IXFR of ..._, but it does not write the slave zone file and it does not serve the new zone version.

This could be a software bug or a documentation error. I don't know.

ahupowerdns commented 5 years ago

So after a little bit of study, it turns out our IXFR code uses methods that are implemented by the generic backends, but not by the BIND backend. In addition, even though the BIND backend returns false on those calls, we do not turn that into a useful error message that tells you what is going on. We also should not attempt IXFR if the backend can't do it.

The fix is to teach the BIND backend what to do (since IXFR is useful there) and to make sure we do not attempt IXFR for backends that can't do it, or at the very least generate a useful error message and good fallback behaviour.

zeha commented 5 years ago

Teaching BIND backend about this might also make it (API) edit capable?