Frequently asked questions about DNS propagation, record types, nameservers, email authentication, and ReviewMyDNS tools.
ReviewMyDNS is a free DNS propagation checker that queries 50+ global DNS servers to verify your DNS records. Check A, AAAA, MX, CNAME, TXT, NS, and SOA records instantly.
This page collects the most common questions about DNS propagation, DNS record types, email authentication, troubleshooting errors, and using ReviewMyDNS tools. Each question links to a detailed guide with step-by-step explanations and examples.
DNS propagation is the most common source of confusion when making DNS changes. When you update a record, resolvers worldwide cache the old value until the TTL (Time to Live) expires. A TTL of 3600 means resolvers can serve the old record for up to one hour. A TTL of 86400 means up to 24 hours. Before any planned DNS change, lower your TTL to 300 seconds and wait 48 hours for the lower TTL to propagate. See Why Is DNS Not Updating After 24 Hours? for a complete troubleshooting walkthrough.
To track propagation progress, use the DNS propagation checker to query 50+ servers worldwide and see exactly which regions have picked up your new records. The How to Check DNS Propagation guide explains how to interpret results.
Understanding which record type to use for a given task prevents common misconfigurations. A records point a hostname to an IPv4 address. AAAA records handle IPv6. CNAME records create aliases from one hostname to another and are restricted to subdomains. MX records route email to the correct mail server. TXT records store SPF, DKIM, DMARC, and domain verification data. NS records delegate a zone to specific nameservers.
The most frequent source of confusion is whether to use an A record or a CNAME. See Difference Between A, CNAME, MX, and TXT Records for a detailed comparison with real-world use cases.
SPF, DKIM, and DMARC are DNS-based email authentication standards that reduce spam and spoofing. SPF lists the IP addresses authorised to send on behalf of your domain. DKIM adds a cryptographic signature to each outbound message. DMARC tells receiving servers what to do when SPF or DKIM fails. All three are stored as TXT records and can be verified with the TXT record checker.
Common error scenarios include NXDOMAIN (domain doesn't exist or missing record), SERVFAIL (resolver couldn't get an answer), and timeout (nameserver unresponsive). Each error page includes causes, diagnostic commands, and step-by-step fixes.