DNS (Domain Name System) is the backbone of the internet, translating human-readable domain names (e.g., example.com) into IP addresses that computers use to identify each other. It consists of multiple record types that define how domain names resolve and function.
An A record maps a domain or subdomain to an IPv4 address (e.g., 192.168.1.1). It directly tells the DNS resolver where to find the server hosting the website or service.
A URL record (commonly referred to as a forwarding record) is used for redirecting traffic from one domain to another. This is typically handled at the DNS provider level and not by the DNS system itself. URL records rely on HTTP-based redirection rather than direct IP mapping.
Since an A record binds the domain to a specific IP address and a URL record attempts to forward traffic elsewhere, they conflict. If both are present, the DNS system does not know whether to resolve the domain to an IP (via A record) or forward it elsewhere (via URL record), causing unpredictable behavior.
Different Functions:
An A record defines where the domain resolves by pointing to an IP.
A URL record redirects traffic at the HTTP level, often requiring additional processing.
Resolution Confusion:
DNS resolvers prioritize A records for IP resolution. If an A record exists, the domain will resolve to an IP, bypassing any URL forwarding.
URL records are not standardized in DNS and depend on DNS provider-specific services, which may not work when an A record is already set.
Breaks Redirection Logic:
If a URL record is configured alongside an A record, the domain may still resolve to the IP set in the A record, preventing the redirection from working correctly.
SSL Requires an A Record or CNAME:
When SSL is enabled, an A record (or a CNAME in some cases) is required to point to the web server handling encrypted traffic.
If a URL record is used instead, the domain forwarding would bypass the SSL-enabled web server, causing certificate mismatches and security issues.
HTTPS Redirection Limitations:
URL forwarding often works through HTTP 301/302 redirects, which require the web server to handle the request.
If SSL is enabled, the request needs to be processed securely by an actual web server at the destination IP, which is impossible if a URL record is in place without an A record.
Conflicts with Certificate Validation:
SSL certificates are issued to specific domains and validated through A records (or CNAMEs). If a URL record is used instead, the domain does not correctly resolve to an SSL-enabled server, leading to SSL errors.
Use a web-based redirection service that supports HTTPS.
Ensure that an A record (or CNAME) is pointing to a hosting provider capable of handling secure redirections.
Avoid relying on URL forwarding if you need SSL; instead, configure redirects at the server level using web hosting settings.
By understanding these conflicts and limitations, you can properly configure DNS records without breaking domain resolution or SSL functionality.
