yammer.com

Nameservers · These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: a1-115.akam.net: "41824.10"; a1-115.akam.net: "41824.11"; a16-66.akam.net: "48878.31"; a16-66.akam.net: "48878.27"; a18-67.akam.net: "48878.27"; a18-67.akam.net: "48878.29"; a28-64.akam.net: "48878.33"; a28-64.akam.net: "48878.29"; a5-65.akam.net: "41824.5"; a5-65.akam.net: "41824.8"; a9-66.akam.net: "41824.4"; a9-66.akam.net: "41824.5"; ns4-01.azure-dns.info: "Knot DNS 3.1.2.1770717641.d6b376aff". Hide or replace the version string.

SOA · The nameservers serve different versions of the zone: 2019123704 on a1-115.akam.net (193.108.91.115), a1-115.akam.net (2600:1401:2::73), a16-66.akam.net (23.211.132.66), a16-66.akam.net (2600:1406:1b::42), a18-67.akam.net (95.101.36.67), a18-67.akam.net (2600:1480:4800::43), a28-64.akam.net (95.100.173.64), a28-64.akam.net (2600:1480:d800::40), a5-65.akam.net (95.100.168.65), a5-65.akam.net (2600:1480:b000::41), a9-66.akam.net (184.85.248.66), a9-66.akam.net (2a02:26f0:117::42); 626 on ns1-01.azure-dns.com (13.107.236.1), ns1-01.azure-dns.com (2603:1061:0:700::1), ns2-01.azure-dns.net (150.171.21.1), ns2-01.azure-dns.net (2620:1ec:8ec:700::1), ns3-01.azure-dns.org (204.14.183.1), ns3-01.azure-dns.org (2a01:111:4000:700::1), ns4-01.azure-dns.info (208.84.5.1), ns4-01.azure-dns.info (2620:1ec:bda:700::1). This is normal for a few minutes after a change; if it lasts, zone transfers to the secondaries are failing.

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.

DNSSEC · DNSSEC is not enabled for this domain. Consider enabling DNSSEC to protect against DNS spoofing attacks.

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: selector1 (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.