ism.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.

SPF · SPF record needs 5 DNS lookups (limit is 10). Problems found: include:sxb1nlsmtp01.prod.sxb1.secureserver.net does not exist or has no records.

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

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: mx00.kundenserver.de, mx01.kundenserver.de

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

DKIM · 1024-bit RSA keys are the minimum and are considered weak today: default (1024 bits), mail (1024 bits). Rotate to a 2048-bit key.

SPF · 1 include/redirect target does not exist or has no records (limit is 2). This usually is a stale include; remove it.

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.