DNS
What is A Record (Address Record)?
A DNS record that maps a hostname to an IPv4 address.
An A record points a domain or subdomain to an IPv4 address, with the AAAA record serving as its IPv6 equivalent. It is the forward half of the lookup that reverse DNS confirms, so a mail server's hostname should have an A record resolving to the same IP its PTR record names. A records also back the tracking-link domains and hostnames referenced in mail headers.
Why it matters for cold email
Forward-confirmed reverse DNS requires the sending host's A record to match its PTR, so a missing or mismatched A record breaks that check and erodes trust. Tracking and custom-domain links in cold email also depend on correct A or CNAME records resolving cleanly, or clicks and opens fail.
Related terms
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