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Delegation · all IPv4 addresses are in 77.95.250.0/24; all IPv6 addresses are in 2a00:1478:40::/48. A single network failure takes all nameservers down; RFC 2182 recommends topologically separate networks (anycast setups are an exception).

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: auth70.dns.internl.net: "PowerDNS Authoritative Server 4.1.13 (built Aug 8 2019 07:52:12 by root@0375968a661f)"; auth80.dns.internl.net: "PowerDNS Authoritative Server 4.1.13 (built Aug 8 2019 07:52:12 by root@0375968a661f)". 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.

MX · Only one MX record found. For better email reliability, consider adding at least one backup MX server.

DKIM · 1024-bit RSA keys are the minimum and are considered weak today: selector2 (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:...".