What is a Reverse DNS (PTR) Record and Why Is It Mandatory?

Email & Business Solutions 24 views Markdown

Forward DNS vs Reverse DNS (PTR)

Standard A records resolve domain names to IP addresses. Reverse DNS (rDNS) performs the reciprocal lookup: querying an IP address to resolve its canonical hostname via a PTR (Pointer) record.

Why Major Providers Reject Missing PTR Records

Mail transfer agents (Google, Microsoft, Yahoo) verify inbound connections against PTR records. If an IP lacks valid rDNS matching its HELO banner:

Inbound mail is outright rejected with 550 5.7.1 error codes.
Surviving messages are routed straight to Junk folders.

Configuring PTR Records at BiHostNet

PTR records can only be configured by the entity controlling the subnet. Open a ticket via the BiHostNet Client Area specifying your IP and desired hostname (e.g., mail.yourdomain.com), and our network engineers will set it up promptly.

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