expert.nl

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: keira.ns.cloudflare.com: "2026.10.2"; will.ns.cloudflare.com: "2026.10.2". Hide or replace the version string.

Records · These records have a TTL below 5m, causing extra queries and slower lookups: MX (1m). Low TTLs are useful just before a planned change. The NS TTL at the parent is 1h and in the zone 1d; resolvers may use either.

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: default (1024 bits), 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:...".