DNS (Domain Name System)

DNS (Domain Name System) is the internet's addressing infrastructure that translates human-readable domain names — like fliplink.me — into the numeric IP addresses computers use to locate servers. When you type a URL into your browser, a chain of DNS servers resolves the domain name to an IP address before the page begins loading. Beyond simple address resolution, DNS stores multiple record types: A records (IPv4 addresses), AAAA records (IPv6), CNAME records (domain aliases), MX records (mail routing), TXT records (verification strings for SPF, DKIM, and DMARC), and NS records (nameserver delegation). Together, these records form the control layer for how your domain behaves across the web, email, and third-party services.

Every time someone opens your digital publication, their browser performs a DNS lookup to resolve your domain. If DNS is misconfigured, readers may see browser errors or be sent to the wrong server entirely. Slow DNS resolution adds latency before any page content begins loading. DNS is also the foundation for [custom domains](/glossary/custom-domain), email authentication, and [SSL](/glossary/ssl) certificate validation, making it a critical piece of your publishing infrastructure. For publishers who serve content on branded URLs, understanding DNS means the difference between a professional experience and a broken link.

DNS is central to FlipLink's [custom domains](/features/custom-domains) feature. To serve your flipbooks from a branded URL like docs.yourcompany.com, you create a CNAME record in your DNS provider pointing that subdomain to FlipLink's servers. FlipLink detects the incoming request, matches it to your account, and handles SSL certificate provisioning automatically — no manual certificate management required. DNS is also involved when configuring email authentication (SPF, DKIM, DMARC) for emails sent through FlipLink's [email templates](/features/email-templates) and sharing features. Proper DNS configuration ensures your publications load quickly, your branded URLs work reliably, and your emails pass authentication checks instead of landing in spam folders.

A DNS lookup follows a specific resolution chain. The browser first checks its local cache, then queries a recursive resolver (typically operated by your ISP or a public service like Cloudflare's 1.1.1.1 or Google's 8.8.8.8). If the resolver does not have the answer cached, it queries the root nameservers, then the TLD (top-level domain) nameservers for `.com`, `.me`, etc., and finally the authoritative nameserver for your specific domain. The authoritative server returns the IP address, and the recursive resolver caches the result according to the record's TTL (Time To Live) value. TTL controls how long other servers remember the answer — a short TTL (300 seconds) means changes propagate quickly but generate more lookups, while a long TTL (86400 seconds) reduces lookup volume but delays propagation of updates. Common DNS record types publishers encounter: - **A / AAAA** — Maps a domain directly to an IP address (IPv4 or IPv6) - **CNAME** — Creates an alias pointing one domain to another (used for custom domains) - **MX** — Directs email to the correct mail server - **TXT** — Stores text strings for domain verification, SPF, DKIM, and DMARC policies

**"DNS changes happen instantly."** DNS updates propagate based on TTL values. If your previous record had a 24-hour TTL, some resolvers will continue serving the old address until that cache expires. Lowering the TTL before making a change can speed up propagation, but there is always some delay. **"DNS is only about websites."** DNS affects email delivery, domain verification for third-party services, security policies (DMARC, DANE), and CDN routing. A single misconfigured TXT record can cause your emails to be rejected as spam. **"CNAME and A records are interchangeable."** They serve different purposes. A records point to a specific IP address, while CNAME records point to another domain name. CNAME records cannot coexist with other record types on the same hostname (the "CNAME at apex" restriction), which is why root domains often use A records while subdomains use CNAME.

1. Identify the subdomain you want to use for your FlipLink publications (e.g., `docs`, `catalog`, `flipbooks`). 2. Log in to your domain registrar or DNS hosting provider. 3. Create a CNAME record for your chosen subdomain pointing to the value provided in your FlipLink dashboard. 4. Set the TTL to a low value (300–600 seconds) during initial setup so you can verify quickly. 5. Wait for DNS propagation (typically a few minutes, occasionally up to a few hours). 6. Return to FlipLink and activate the custom domain — SSL will be provisioned automatically. 7. Test the domain by visiting it in a browser and confirming your flipbook loads correctly. 8. Once everything works, you can increase the TTL to a longer value (3600–86400 seconds) to reduce lookup overhead.