hu-berlin.de

SOA · The nameservers serve different versions of the zone: 2019101598 on dns-3.dfn.de (193.174.75.58), dns-3.dfn.de (2001:638:d:b103::1); 2019101601 on ns.tu-berlin.de (130.149.7.7), ns.tu-berlin.de (2001:638:809:7::7); 2019101612 on buffy.cms.hu-berlin.de (141.20.2.3), hpcom.rz.hu-berlin.de (141.20.1.3), suncom.rz.hu-berlin.de (141.20.1.31). This is normal for a few minutes after a change; if it lasts, zone transfers to the secondaries are failing.

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.

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: ir1.cms.hu-berlin.de, ir2.cms.hu-berlin.de

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.