hamburger-kunsthalle.de

Delegation · The addresses at the parent (glue) differ from the addresses in the zone: ns1.uvensys.de (glue 37.208.104.2, zone 37.208.104.2, 2a00:d0c0:d3:1::100); ns2.uvensys.de (glue 37.208.110.2, zone 37.208.110.2, 2a00:d0c0:d4:1::100). Update the glue at your registrar.

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns1.uvensys.de: "PowerDNS Authoritative Server 4.7.3"; ns2.uvensys.de: "PowerDNS Authoritative Server 4.7.3". Hide or replace the version string.

SOA · expire 1d is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 1d must be longer than refresh + retry. Current values: refresh 1d, retry 1h, expire 1d, negative TTL 1h.

DNSSEC · The zone is not signed with DNSSEC, so answers can be spoofed. Enable DNSSEC at your DNS provider and publish the DS record at your registrar.

Records · These records have a TTL below 5m, causing extra queries and slower lookups: A (1m), AAAA (1m). Low TTLs are useful just before a planned change. The NS TTL at the parent is 1d and in the zone 1h; resolvers may use either.

DMARC · DMARC policy is set to 'quarantine'. Consider upgrading to 'reject' for stronger protection once you've verified legitimate emails are passing authentication.

DKIM · The _domainkey name exists but no DKIM key was found under the common selectors. Selectors are provider-specific; check yours with -selector.

DNSSEC · DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.

MX · The following MX hosts could not be resolved to IPv6 addresses: mx1.ondataport.de, mx2.ondataport.de

DMARC · DMARC record has no rua tag, so you receive no aggregate reports about who sends mail as your domain. Add rua=mailto:...

TLS · MTA-STS is not configured, so other mail servers fall back to unencrypted delivery when TLS fails or is stripped by an attacker. Publish a _mta-sts TXT record and a policy at https://mta-sts.<domain>/.well-known/mta-sts.txt.