nerdculture.de

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns.windfluechter.net: "PowerDNS Authoritative Server 5.1.5 (built Oct 7 2026 06:13:02 by root@localhost)". Hide or replace the version string.

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

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: selector1 (1024 bits). Rotate to a 2048-bit key.

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:...".