3sat.de

Delegation · The nameservers at the parent and in the zone should be the same. Only in the zone: a10-64.akam.net. a1-107.akam.net, a10-64.akam.net, a11-65.akam.net, a14-66.akam.net, a22-67.akam.net, a9-66.akam.net, ns01.zdf.de, ns02.zdf.de report NS a1-107.akam.net a10-64.akam.net a11-65.akam.net a14-66.akam.net a22-67.akam.net a9-66.akam.net ns01.zdf.de ns02.zdf.de.

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: a1-107.akam.net: "41824.7"; a1-107.akam.net: "41824.10"; a10-64.akam.net: "48878.30"; a10-64.akam.net: "48878.33"; a11-65.akam.net: "41824.10"; a11-65.akam.net: "41824.6"; a14-66.akam.net: "48878.29"; a14-66.akam.net: "48878.33"; a22-67.akam.net: "48878.30"; a9-66.akam.net: "41824.6"; a9-66.akam.net: "41824.4". Hide or replace the version string.

SOA · refresh 15m is outside 20m–1d; negative caching TTL (minimum) 3m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 15m, retry 5m, expire 30d, negative TTL 3m.

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.

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: mail.zdf.de

MX · Only one MX record found. For better email reliability, consider adding at least one backup MX server.

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.