hans-bredow-institut.de

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: a2511.mx.srv.dfn.de, b2511.mx.srv.dfn.de, c2511.mx.srv.dfn.de

DMARC · DMARC policy only applies to 10% of failing mail (pct=10). Raise pct to 100 once you are confident in your setup.

DMARC · DMARC subdomain policy is sp=none, so spoofed mail from subdomains is not blocked. Consider sp=quarantine or sp=reject.

DMARC · These report addresses are in another domain that has not agreed to receive your reports, so receivers will not send them: mailto:dmarc_rua@hbiteam.de (needs hans-bredow-institut.de._report._dmarc.hbiteam.de); mailto:dmarc_ruf@hbiteam.de (needs hans-bredow-institut.de._report._dmarc.hbiteam.de). Ask the report provider to publish the record, or check the address.

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.

TLS · MTA-STS or DANE is used without TLS-RPT, so you get no reports when senders fail to deliver because of TLS problems. Publish _smtp._tls TXT "v=TLSRPTv1; rua=mailto:...".