DNS (Domain Name System) is a system that translates human-friendly domain names (e.g., example.com) into computer-readable IP addresses. Without proper DNS configuration, your website, email, or other services will simply not function.
The Role of DNS: DNS links your domain to servers hosting your data. For example, when a user enters a website address, DNS directs the browser where to find it.
Consequences of Errors: Incorrect settings can cause website downtime (e.g., if an A-record points to the wrong IP) or email loss (if MX records are misconfigured).
Primary Use Cases:
- Linking a domain to web hosting for site accessibility
- Configuring corporate email (e.g., via Gmail or Yandex.Mail)
- Connecting CDNs (e.g., Cloudflare) for acceleration and security
- Creating subdomains (e.g., blog.example.com)
Registrar vs. DNS Hosting: Registrar is the company where you purchase domains (e.g., Reg.ru). DNS hosting is a service managing your DNS records. Registrars often provide basic DNS hosting, but third-party services (e.g., Cloudflare) can be used.
NS Servers and DNS Zone: NS servers (Name Servers) store your domain's DNS records. DNS zone is the complete set of records for a domain.
TTL (Time to Live): Duration (in seconds) DNS records are cached. Low TTL (300-600 sec) speeds up updates; high TTL (86400 sec) reduces server load.
Preparation
Gathering Required Information
Before configuration, collect:
- Server IPs: Web server IP (for A-records) and mail server IPs (for MX records)
- Email Data:
- MX records (pointing to mail servers)
- SPF, DKIM, DMARC (for spam/spoofing protection)
- CNAME: Required for CDNs or external services (e.g., analytics)
- Current Record Check: Use
nslookup example.comordig A example.comto verify existing settings
Strategy Selection
- Registrar vs. Third-Party DNS: Registrar DNS is user-friendly, but third-party services (Cloudflare, Yandex) offer DDoS protection and analytics
- When to Change NS Servers: Switch to external DNS hosting for advanced features (e.g., geo-routing or dynamic IP updates via API)
Step-by-Step Record Configuration via Registrar
Accessing Control Panel
- Interfaces: Each registrar has its own panel (Reg.ru, Nic.ru, GoDaddy, Namecheap). Look for "DNS Management" or "Zone Editor"
- Where to Find: Search for "DNS Records" or "Zone Editor" tab
Key Record Types (with Examples)
| Record Type | Purpose | Example Value |
|---|---|---|
| A | IPv4 address | 192.0.2.1 |
| AAAA | IPv6 address | 2001:db8::1 |
| CNAME | Alias | shop.example.com. |
| MX | Mail server | 10 mail.example.com. |
| TXT | Verification, SPF | "v=spf1 include:_spf.google.com ~all" |
| NS | Delegation | ns1.cloudflare.com. |
| SRV | Service records | 10 5 5060 sip.example.com. |
Practical Cases
1. Linking Domain to Hosting:
- Add A-records for
@(root domain) andwwwwith your server's IP - Example:
@ A 192.0.2.1andwww A 192.0.2.1
2. Gmail/Yandex.Mail Setup:
MX @ 10 aspmx.l.google.com.
TXT @ "v=spf1 include:_spf.google.com ~all"
TXT _dmarc "v=DMARC1; p=quarantine; rua=mailto:report@example.com"3. Connecting Cloudflare:
- Replace NS servers with Cloudflare's (e.g.,
ns1.cloudflare.com) - Cloudflare auto-imports existing records
Special Settings
- Wildcard Records:
*.example.comhandles all subdomains without explicit records. Individual subdomain records (e.g.,blog.example.com) take priority - Redirects: Some registrars support URL redirects in their panels
- Subdomains:
mail.example.com- for emailcdn.example.com- for static files
Working with DNS Hosting (Cloudflare, Yandex)
Transferring DNS Management
- Changing NS Servers: Update NS servers in registrar's panel
- Propagation Time: Changes typically take hours but may require up to 48 hours globally
Benefits of External DNS Hosting
- DDoS protection (Cloudflare filters malicious traffic)
- DDNS (API support for dynamic IP updates)
- Geo-routing (traffic directs to nearest server)
- Analytics (DNS query statistics)
- Encryption (DoH/DoT support)
Advanced Configuration
- DNSSEC (prevents record tampering)
- Rewrite rules (configure redirects at DNS level)
- TTL management (lower before changes for faster updates)
Verification and Testing
Validation Tools
- Online Services: DNSCHECKER, MXToolbox
- Commands:
nslookup example.com
dig A example.com +short
dig MX example.com
Common Errors
- Missing trailing dot (use
example.com.) - CNAME conflict (can't coexist with other records)
- MX priority (lower number = higher priority)
- Caching (old records persist due to TTL)
Validation Checklist
- A-records point to correct IPs
- MX records match email provider
- TXT records (SPF/DKIM/DMARC) are valid
- HTTPS works without errors (verify domain in certificate)
Security and Optimization
DNS Protection
- 2FA (enable two-factor authentication)
- Access restrictions (allow logins only from trusted IPs)
- Audits (regularly review for outdated records)
Performance Optimization
- TTL (low: 300-600 sec for dynamics; high: 86400 sec for static)
- Anycast DNS (accelerates responses via distributed servers)
- Caching (use resolvers to reduce load)
Common Issues & Solutions
1. Website Unavailable:
- Verify NS servers
- Wait for propagation (4-12 hours typically; up to 48 hours)
2. Email Delivery Failure:
- Check SPF/DKIM/DMARC
- Ensure IP isn't blacklisted (Spamhaus)
3. SSL/TLS Errors:
- Confirm domain name matches certificate
- Renew certificates (e.g., Let's Encrypt)
Key Recommendations:
- Back up zone before changes
- Use external DNS hosting for critical projects
- Update records for dynamic servers via API regularly
Additional Resources:
- SPF/DKIM/DMARC generators (mxtoolbox.com)
- DNS monitoring (UptimeRobot)
- Migration tools (Cloudflare Transfer)
Proper DNS configuration is like a building's found
