umm.de

Delegation · The addresses at the parent (glue) differ from the addresses in the zone: ns1.twl-kom.de (glue 217.151.144.10, zone 217.151.144.10, 2a00:e58:1:9:217:151:144:10). Update the glue at your registrar.

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: gate4.umm.de: "9.20.23". Hide or replace the version string.

SOA · retry 1h should be shorter than refresh 1h. Current values: refresh 1h, retry 1h, expire 21d, 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.

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: ip3.umm.de, ip2.umm.de, ip.umm.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.