SSL, DNS & Domains

Why SSL, DNS & Domains Matter

Users type a domain name and expect your application to load instantly over a secure connection. Between that keystroke and the rendered page sit DNS resolution, SSL handshakes, CDN edge caching, and routing decisions. When any of these break, your application is unreachable - even if the servers are running perfectly.

SSL certificate expiration is the most common self-inflicted outage. A certificate expires at 3 AM, and suddenly every user sees a browser warning that your site is dangerous. Let’s Encrypt made certificates free, but someone still needs to ensure automatic renewal works. Managed certificates from cloud providers help, but they have their own edge cases - domain validation failures, propagation delays, and wildcard certificate limitations.

DNS misconfiguration is the second most common. A typo in a CNAME record. Missing A records after a migration. TTL values that cause changes to take hours instead of minutes. DNS is the one piece of infrastructure where a mistake at 2 PM is still causing problems at 8 PM because resolvers cached the wrong answer.

What We Build

SSL/TLS Configuration:

• Automatic certificate provisioning with Let’s Encrypt or cloud-native certificate managers
• Certificate renewal monitoring with alerts before expiration
• Wildcard certificates for applications with dynamic subdomains
• SSL termination at the load balancer or CDN edge
• HSTS configuration with proper preload settings
• Certificate pinning for mobile applications when required

DNS Management:

• DNS configuration as code - version-controlled, reviewable, reproducible
• Proper record types: A, AAAA, CNAME, MX, TXT, SRV
• SPF, DKIM, and DMARC records for email deliverability
• Low TTL values during migrations, higher values for stability
• Health-check based DNS failover
• Split-horizon DNS for internal vs external resolution

CDN Configuration:

• Cloudflare, CloudFront, or Fastly based on requirements
• Cache rules that balance performance with content freshness
• Edge functions for request transformation and routing
• DDoS protection and rate limiting at the edge
• Geographic routing for multi-region deployments
• Custom cache keys for personalized content

Domain Management:

• Domain registration and renewal tracking
• Subdomain strategy for applications, APIs, and documentation
• Domain migration with zero-downtime cutover plans
• WHOIS privacy and domain locking
• Multi-domain certificate management

Our Experience Level

We’ve managed DNS and SSL for applications serving millions of requests from custom domains to multi-region deployments with geographic routing. We’ve migrated domains between registrars, switched DNS providers without downtime, and debugged certificate chain issues that only affected specific browsers.

We’ve configured Cloudflare for DDoS protection and edge caching, CloudFront for AWS-native applications, and Fastly for teams that needed edge compute capabilities. We’ve set up custom domain support for SaaS platforms where each customer gets their own subdomain or brings their own domain.

We’ve handled the incidents too. Expired certificates at midnight. DNS propagation that took longer than expected. CDN cache that served stale content after a critical update. Email that went to spam because SPF records were missing. Each incident improved our checklists and monitoring.

When to Use It (And When Not To)

Every production application needs SSL and DNS configuration. Platforms like Vercel and Netlify handle this automatically for simple deployments. If your platform manages certificates and DNS for you, let it.

When you need custom domains, multiple subdomains, or specific DNS configurations, you need intentional DNS management. This includes API subdomains, staging environments on separate subdomains, email configuration, and domain verification for third-party services.

When you serve static assets, have global users, or need DDoS protection, add a CDN. The performance improvement from edge caching is dramatic - response times drop from hundreds of milliseconds to single digits for cached content. The cost is minimal compared to the performance gain.

For SaaS applications where customers bring custom domains, SSL and DNS become a product feature. You need automated certificate provisioning, domain verification workflows, and monitoring for certificate renewal failures.

Common Challenges and How We Solve Them

Certificate expiration causing outages. The most preventable outage there is. We set up automated renewal with monitoring. Alerts fire 30, 14, and 7 days before expiration. If automated renewal fails, we know immediately - not when users report the site is down.

DNS changes that take hours to propagate. TTL values are set too high, so DNS changes are cached for hours. Before making changes, we lower TTL values. After changes propagate, we raise TTL for stability. During migrations, we plan for propagation windows.

Email going to spam. Missing or incorrect SPF, DKIM, and DMARC records. We configure all three properly, test with mail validation tools, and monitor deliverability. Transactional emails (password resets, receipts) going to spam is a product-breaking issue.

CDN serving stale content after deploys. Users see the old version because the CDN cached it. We implement proper cache invalidation as part of the deployment pipeline. Cache-busted asset filenames for static content. API responses with appropriate cache headers.

Mixed content warnings after enabling HTTPS. The application loads over HTTPS but references HTTP resources. We audit all resource URLs, update hardcoded HTTP references, and configure content security policies. The goal is a clean HTTPS deployment with no mixed content.