langchain.com

SOA · expire 3d is shorter than 7d; secondaries stop answering too soon when the primary is down. Current values: refresh 6h, retry 1h, expire 3d, negative TTL 5m.

DNSSEC · NSEC3 uses 1 iteration and a 8-byte salt. RFC 9276 recommends 0 iterations and no salt: extra iterations cost resolvers CPU and add no real protection, and some validators treat high counts as insecure.

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

DMARC · These report addresses are in another domain that has not agreed to receive your reports, so receivers will not send them: mailto:postmaster@langchain.dev (needs langchain.com._report._dmarc.langchain.dev). Ask the report provider to publish the record, or check the address.

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.