80216bdbea2363da2a2d11665d2352630509c68bcb4e67331d8c7293.eu.rspf.letsdmarc.com IXFR zone transfer

Changes since SOA version

IXFR is a zone transfer request that returns changes since a specific SOA version. Enter the SOA version to request changes since then.

Zone transfer refused The zone transfer was refused by the DNS server.
That's a security best practice.