// Check domain length if (strlen($domain) > 253) throw new Exception("Domain name too long");
function validate_email_domain($email) if (!filter_var($email, FILTER_VALIDATE_EMAIL)) return false; // Extract domain from email $domain = substr(strrchr($email, "@"), 1); // Check for MX records if (checkdnsrr($domain, "MX")) return true; return false; Use code with caution. Validation - Manual - PHP
Example #1 Validating email addresses with filter_var() $email_a = 'joe@example.com'; $email_b = 'bogus'; if (filter_var($email_a, validate email domain php
return ["valid" => true, "reason" => "Email domain is valid"];
// Use the mail exchanger with highest priority $mx_host = $mx_records[0]; // Check domain length if (strlen($domain) > 253)
function is_domain_valid($domain) // Check for MX records first if (checkdnsrr($domain, "MX")) return true; // Fallback to A record if no MX is found return checkdnsrr($domain, "A"); if (is_domain_valid($domain)) echo "Domain is valid and can receive email."; else echo "Domain does not exist or cannot receive email."; Use code with caution. Copied to clipboard Complete Validation Function Here is a reusable function combining all steps:
public function validate($email) $domain = substr(strrchr($email, "@"), 1); DNS lookups are not instant
Validating an email domain in PHP is a balancing act between accuracy, speed, and complexity.
DNS lookups are not instant. A standard DNS check in PHP is a blocking operation. If the user enters a typo, the DNS resolver might take several seconds to time out before returning false . In a web request context, this freezes the user experience.