Introduction to DNS and How It Works

DNS (Domain Name System) is the internet's phone book. It translates human-readable domain names (like example.com) into IP addresses (like 192.168.1.1) that computers use to communicate. How DNS Works You type www.example.com in your browser Your computer asks a DNS server: "What is the IP for example.com?" The DNS server responds: "192.168.1.1" Your browser connects to 192.168.1.1 The website loads DNS Hierarchy DNS is a hierarchical system: Level Example Purpose Root . (dot) Top of DNS hierarchy TLD .com, .net, .org Top-level domains Domain example.com Your registered domain Subdomain www.example.com Prefix to your domain Key DNS Terms Nameserver: Server that stores DNS records for domains DNS Record: An entry that maps a name to a value (IP, hostname, etc.) TTL (Time to Live): How long DNS info is cached Propagation: Time for DNS changes to spread globally Zone: A portion of the DNS namespace managed together Common DNS Record Types Record Purpose Example A Maps domain to IPv4 address example.com > 192.168.1.1 AAAA Maps domain to IPv6 address example.com > 2001:db8::1 CNAME Alias to another domain www > example.com MX Mail server for domain mail.example.com TXT Text information (SPF, verification) v=spf1 include:... NS Nameservers for domain ns1.sameservers.com Why DNS Matters Without DNS, you would need to remember IP addresses DNS controls where your website and email go Misconfigured DNS = website and email not working DNS is critical for security (SPF, DKIM, DMARC) Ahosting Nameservers To use Ahosting DNS, point your domain to: ns1.sameservers.com ns2.sameservers.comns3.sameservers.com Change nameservers at your domain registrar.

How to Access and Use the Zone Editor in cPanel

The Zone Editor in cPanel allows you to view and modify DNS records for your domains. This is where you configure A records, CNAME records, MX records, and more. Accessing Zone Editor Log into cPanel Go to Domains section Click Zone Editor Find your domain and click Manage Zone Editor Interface The Zone Editor displays all DNS records for your domain: Name: The hostname or subdomain TTL: Time to live in seconds Type: Record type (A, CNAME, MX, etc.) Record: The value (IP address, hostname, etc.) Actions: Edit or delete the record Adding a New Record Click + Add Record dropdown Select the record type (A, CNAME, MX, TXT, etc.) Fill in the required fields Click Add Record Quick Add Options Zone Editor provides quick add buttons for common records: + A Record: Add an A record + CNAME Record: Add a CNAME record + MX Record: Add a mail exchanger record + Add Record: Dropdown for all record types Editing an Existing Record Find the record in the list Click Edit next to the record Modify the values Click Save Record Deleting a Record Find the record Click Delete Confirm deletion Warning: Deleting critical records (A, MX, NS) can break your website or email. Resetting to Default If you have made mistakes and want to start fresh: Click Actions dropdown for the domain Select Reset Zone Confirm the reset Warning: This removes all custom records. Viewing Raw Zone File For advanced users, you can view the raw zone file: In Zone Editor, scroll down Click Manage for your domain All records are displayed in a table Best Practices Document changes before making them Use low TTL (300) during changes, higher (14400) for stable records Test changes using online DNS tools Wait for propagation before troubleshooting Common Tasks Point domain to new server: Edit A record Set up subdomain: Add A or CNAME record Configure email: Add/edit MX records Verify domain ownership: Add TXT record Enable email security: Add SPF/DKIM/DMARC TXT records

Understanding A Records and AAAA Records

A and AAAA records are the most fundamental DNS records. They point domain names to IP addresses where your website is hosted. What is an A Record? An A (Address) record maps a domain name to an IPv4 address. example.com. IN A 192.168.1.1 www.example.com. IN A 192.168.1.1 What is an AAAA Record? An AAAA (Quad-A) record maps a domain name to an IPv6 address. example.com. IN AAAA 2001:0db8:85a3:0000:0000:8a2e:0370:7334 AAAA records are becoming more important as IPv6 adoption grows. Adding an A Record in cPanel Go to Zone Editor Click Manage for your domain Click + A Record Enter: Name: Subdomain (e.g., "blog") or leave empty for root domain Address: The IPv4 address (e.g., 192.168.1.1) TTL: Time to live (default 14400 is fine) Click Add Record Common A Record Configurations Name Points To Purpose @ (or blank) Server IP Root domain (example.com) www Server IP www.example.com blog Server IP blog.example.com shop Different IP shop.example.com mail Mail server IP mail.example.com Multiple A Records You can have multiple A records for the same name (round-robin DNS): example.com. A 192.168.1.1 example.com. A 192.168.1.2 Traffic is distributed between the IPs. Used for basic load balancing. Finding Your Server IP Log into cPanel Look at the right sidebar Find Shared IP Address Or check your welcome email When to Use A vs CNAME Use A Record Use CNAME Root domain (@) Subdomains pointing to another hostname When you have a specific IP When pointing to a service (CDN, cloud) Mail servers (with MX) Aliases to main domain Troubleshooting A Records Website not loading after change Wait for DNS propagation (up to 48 hours) Check IP address is correct Verify domain is added to server Clear browser cache and try again Check current A record Use online tools or command line: nslookup example.com dig example.com A

Understanding MX Records for Email

MX (Mail Exchanger) records specify which mail servers handle email for your domain. Without correct MX records, you cannot receive email. How MX Records Work Someone sends email to you@example.com Sender's mail server looks up MX records for example.com MX record says: "Send mail to mail.example.com with priority 10" Sender delivers email to that mail server MX Record Structure example.com. MX 10 mail.example.com. example.com: The domain MX: Record type 10: Priority (lower = higher priority) mail.example.com: Mail server hostname MX Priority Multiple MX records with different priorities provide backup: example.com. MX 10 mail.example.com. example.com. MX 20 backup.example.com. Priority 10 is tried first (primary) If unavailable, priority 20 is used (backup) Lower number = higher priority Adding MX Records in cPanel Go to Zone Editor Click Manage for your domain Click + MX Record Enter: Priority: Number (e.g., 10) Destination: Mail server hostname TTL: Time to live Click Add Record Ahosting Default MX Record For email hosted with Ahosting: Priority: 0 Destination: mail.yourdomain.com Common Third-Party MX Records Google Workspace 1 ASPMX.L.GOOGLE.COM 5 ALT1.ASPMX.L.GOOGLE.COM 5 ALT2.ASPMX.L.GOOGLE.COM 10 ALT3.ASPMX.L.GOOGLE.COM 10 ALT4.ASPMX.L.GOOGLE.COM Microsoft 365 0 yourdomain-com.mail.protection.outlook.com Zoho Mail 10 mx.zoho.com 20 mx2.zoho.com 50 mx3.zoho.com Email Routing in cPanel When using external email (Google, Microsoft): Go to Email > Email Routing Select your domain Choose Remote Mail Exchanger Click Change This tells cPanel not to handle email locally. MX Record Requirements MX target must be a hostname, not an IP address The hostname must have an A record Cannot use CNAME as MX target MX records are always for the root domain (not subdomains) Troubleshooting MX Records Not receiving email Check MX records are correct Verify mail server hostname has A record Check email routing in cPanel Wait for DNS propagation Check MX records nslookup -type=MX example.com dig example.com MX Online tools MXToolbox MX Lookup DNS Checker MX Lookup

Understanding TXT Records

TXT (Text) records store text information in DNS. They are commonly used for domain verification, email authentication (SPF, DKIM, DMARC), and other purposes. Common TXT Record Uses Purpose Example SPF (email authentication) v=spf1 include:_spf.google.com ~all DKIM (email signing) v=DKIM1; k=rsa; p=MIGfMA0... DMARC (email policy) v=DMARC1; p=quarantine; rua=mailto:... Domain verification google-site-verification=abc123... SSL verification _acme-challenge.example.com Adding a TXT Record in cPanel Go to Zone Editor Click Manage for your domain Click + Add Record dropdown Select Add TXT Record Enter: Name: Subdomain or @ for root (depends on purpose) Record: The TXT value TTL: Time to live Click Add Record SPF Record SPF specifies which servers can send email for your domain: v=spf1 +a +mx +ip4:192.168.1.1 include:_spf.google.com ~all v=spf1: SPF version +a: Allow domain A record IP +mx: Allow MX server IPs include: Include another domain SPF ~all: Soft fail all others DKIM Record DKIM adds a digital signature to emails. The record name includes a selector: Name: default._domainkey Value: v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4... DKIM is usually set up automatically in cPanel. DMARC Record DMARC tells receivers what to do when SPF/DKIM fails: Name: _dmarc Value: v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com Domain Verification Records Google Search Console Name: @ Value: google-site-verification=xxxxxxxxxxxxxxxx Microsoft 365 Name: @ Value: MS=msxxxxxxxx Facebook Domain Verification Name: @ Value: facebook-domain-verification=xxxxxxxx Multiple TXT Records You can have multiple TXT records for the same name: @ TXT "v=spf1 include:_spf.google.com ~all" @ TXT "google-site-verification=abc123" @ TXT "facebook-domain-verification=xyz789" TXT Record Length Limits Single string: Maximum 255 characters For longer records: Split into multiple strings cPanel usually handles this automatically Checking TXT Records nslookup -type=TXT example.com dig example.com TXT Troubleshooting Verification failing: Check exact value matches, wait for propagation SPF failing: Verify syntax, check all sending servers included Record not showing: DNS propagation can take up to 48 hours

How to Change Nameservers for Your Domain

Nameservers control which DNS servers manage your domain's records. To use Ahosting DNS, you need to point your domain to Ahosting nameservers. Ahosting Nameservers ns1.sameservers.com ns2.sameservers.com ns3.sameservers.com Where to Change Nameservers Nameservers are changed at your domain registrar - where you registered/purchased the domain. Common registrars: GoDaddy Namecheap Google Domains Cloudflare Name.com Hover Note: This is different from your hosting provider. You may have registered your domain elsewhere. General Steps to Change Nameservers Log into your domain registrar account Find the domain in your account Look for "Nameservers", "DNS", or "Domain Settings" Select "Custom nameservers" or "Change nameservers" Enter Ahosting nameservers: Nameserver 1: ns1.sameservers.com Nameserver 2: ns2.sameservers.com Save changes Registrar-Specific Instructions GoDaddy Log into GoDaddy Go to My Products > Domains Click domain name Scroll to Nameservers Click Change Select Enter my own nameservers Enter Ahosting nameservers Click Save Namecheap Log into Namecheap Go to Domain List Click Manage next to domain Find Nameservers section Select Custom DNS Enter Ahosting nameservers Click checkmark to save Google Domains Log into Google Domains Select the domain Click DNS in left menu Select Custom name servers Enter Ahosting nameservers Click Save After Changing Nameservers DNS propagation takes time: Can take up to 24-48 hours worldwide Usually starts working within a few hours Some locations may resolve faster than others Do not make additional changes during propagation Checking Nameserver Status Verify your nameservers have updated: nslookup -type=NS example.com dig example.com NS Or use online tools: WhatsMyDNS DNS Checker Nameservers vs DNS Records Nameservers DNS Records Set at registrar Set at nameserver provider Points to DNS provider Defines domain behavior Changed rarely Changed as needed Common Issues Site not working after change: Wait for propagation, clear browser cache Email stopped working: MX records need to exist at new nameserver Registrar locked domain: Unlock domain before changing nameservers

Understanding DNS Propagation

DNS propagation is the time it takes for DNS changes to spread across the internet. During this period, different users may see different results. What is DNS Propagation? When you change a DNS record: You update the record at your DNS provider DNS servers worldwide need to get the new information Old cached records expire based on TTL Eventually all servers have the new record How Long Does Propagation Take? Change Type Typical Time Maximum Time A record change 1-4 hours 48 hours Nameserver change 12-24 hours 48-72 hours New subdomain Minutes to hours 24 hours TXT record 1-4 hours 48 hours What Affects Propagation Time? TTL (Time to Live) TTL tells DNS servers how long to cache a record: Low TTL (300 seconds): Faster propagation, more DNS queries High TTL (86400 seconds): Slower propagation, fewer queries Lower your TTL before making changes, then raise it after. ISP DNS Caching Some ISPs cache DNS longer than specified TTL. You cannot control this. Browser and OS Caching Your computer and browser also cache DNS. Clear these caches to see changes faster. Checking Propagation Status Use these tools to check propagation worldwide: WhatsMyDNS.net DNS Checker NSLookup.io These show DNS results from servers in different locations. Speeding Up Propagation Before Making Changes Lower TTL to 300 seconds (5 minutes) Wait for old TTL to expire (e.g., if TTL was 14400, wait 4 hours) Make your DNS changes After propagation, raise TTL back to 14400 or higher Clear Local DNS Cache Windows: ipconfig /flushdns Mac: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder Chrome: chrome://net-internals/#dns > Clear host cache During Propagation Some users see old site, some see new Email may go to old or new server Avoid making additional changes Keep old server running until fully propagated Common Propagation Issues Site shows old content Clear browser cache Try incognito/private mode Try different network (mobile data) Wait for propagation to complete Works for some, not others This is normal during propagation. Different locations update at different times. Still not working after 48 hours Verify DNS records are correct Check nameservers are correct Ensure domain is not expired Contact support for assistance

How to Set Up a Subdomain with DNS

Subdomains are prefixes to your main domain (like blog.example.com). They can point to the same server, different servers, or third-party services. Creating a Subdomain There are two steps: Add DNS record for the subdomain Configure hosting to serve content (if hosting locally) Method 1: Subdomain on Same Server If hosting the subdomain on Ahosting: Go to cPanel > Domains Click Create A New Domain Enter full subdomain: blog.example.com Click Submit cPanel automatically creates the DNS record and folder. Method 2: Subdomain to Different IP If pointing to a different server: Go to Zone Editor Click + A Record Name: blog (the subdomain prefix) Address: The destination IP address Click Add Record Method 3: Subdomain to External Service If pointing to a third-party service (Shopify, Tumblr, etc.): Go to Zone Editor Click + CNAME Record Name: shop (the subdomain prefix) Record: shops.myshopify.com (service hostname) Click Add Record Common Subdomain Configurations Subdomain Record Type Points To www A or CNAME Same server or example.com blog A Same server IP shop CNAME shops.myshopify.com mail A Mail server IP staging A Development server IP app A Application server IP Wildcard Subdomain A wildcard record handles all undefined subdomains: *.example.com A 192.168.1.1 Any subdomain not specifically defined will use this record. SSL for Subdomains Each subdomain needs its own SSL certificate or a wildcard certificate. AutoSSL: Automatically covers subdomains added in cPanel Wildcard SSL: Covers *.example.com with one certificate External services: Usually provide their own SSL Subdomain Email You can create email addresses for subdomains: support@help.example.com info@blog.example.com MX records can be added for subdomains if needed. Testing Subdomain Setup Wait for DNS propagation (few minutes to hours) Use nslookup or dig to verify record: nslookup blog.example.com Try accessing in browser Troubleshooting Subdomain not resolving Check DNS record exists in Zone Editor Wait for propagation Verify no typos in subdomain name Subdomain shows wrong content Verify document root is correct in cPanel Check A record points to correct IP Clear browser cache SSL not working on subdomain Run AutoSSL from cPanel Wait for certificate issuance Check subdomain is added in cPanel Domains

DNS Troubleshooting Guide

This guide covers common DNS problems and how to diagnose and fix them. Diagnostic Tools Command Line Tools # Look up A record nslookup example.com # Look up specific record type nslookup -type=MX example.com # Detailed DNS query dig example.com # Query specific DNS server dig @8.8.8.8 example.com # Trace DNS resolution dig +trace example.com Online Tools WhatsMyDNS - Global propagation check MXToolbox - Comprehensive DNS tools DNS Checker - Multiple record types IntoDNS - DNS health check Issue: Domain Not Resolving Symptoms Website shows "Server not found" or "DNS_PROBE_FINISHED_NXDOMAIN" nslookup returns "Non-existent domain" Causes and Solutions Domain expired: Renew at registrar Nameservers not set: Configure nameservers at registrar No A record: Add A record in Zone Editor DNS propagation: Wait up to 48 hours Domain suspended: Contact registrar Issue: Wrong IP Address Returned Symptoms Website shows different/wrong content nslookup shows incorrect IP Causes and Solutions Outdated cached DNS: Clear local DNS cache, wait for propagation Wrong A record: Update A record in Zone Editor Multiple A records: Remove incorrect records Using wrong nameservers: Verify nameservers at registrar Issue: Email Not Working Symptoms Not receiving emails Sending emails bounce back Causes and Solutions Wrong MX records: Verify MX records point to correct mail server Missing MX records: Add MX records Email routing: Check cPanel Email Routing settings SPF/DKIM issues: Verify TXT records for email authentication Issue: SSL Certificate Errors Symptoms Browser shows "Not Secure" warning Certificate name mismatch DNS-Related Causes CNAME pointing to wrong host: Update CNAME record Domain not in certificate: Ensure DNS points to server with valid SSL CAA record blocking: Check CAA records allow your CA Issue: Subdomain Not Working Causes and Solutions No DNS record: Add A or CNAME record for subdomain Wrong record type: Use A for IP, CNAME for hostname Not added in cPanel: Add subdomain in cPanel Domains Propagation: Wait for DNS to update Issue: Slow DNS Resolution Causes and Solutions DNS server issues: Try different DNS resolver (8.8.8.8) Long CNAME chains: Reduce CNAME hops Slow authoritative servers: Contact hosting provider Common DNS Errors Error Meaning Solution NXDOMAIN Domain does not exist Check domain registration and nameservers SERVFAIL DNS server failed Try different DNS server, check records REFUSED Server refused query Verify nameservers are correct TIMEOUT No response from server Check internet, try different DNS When to Contact Support Server-side DNS issues Nameserver not responding Complex DNS configurations Issues persisting after 48 hours Provide support with: Domain name, expected result, actual result, dig/nslookup output, when problem started.

Understanding CNAME Records

DNS Management Updated May 2026

A CNAME (Canonical Name) record creates an alias from one domain name to another. Instead of pointing to an IP address, it points to another hostname.

How CNAME Works

www.example.com.    CNAME    example.com.

When someone visits www.example.com:

DNS looks up www.example.com
Finds CNAME pointing to example.com
Looks up A record for example.com
Returns the IP address

Common CNAME Uses

Subdomain	Points To	Purpose
www	example.com	www alias to root
blog	mysite.wordpress.com	External blog platform
shop	shops.myshopify.com	E-commerce platform
mail	ghs.google.com	Google Workspace
cdn	d1234.cloudfront.net	CDN distribution

Adding a CNAME Record in cPanel

Go to Zone Editor
Click Manage for your domain
Click + CNAME Record
Enter:
- Name: The subdomain (e.g., www, blog, shop)
- Record: The target hostname (e.g., example.com)
- TTL: Time to live (default 14400)
Click Add Record

CNAME Rules and Restrictions

Cannot use CNAME for root domain: example.com cannot be a CNAME (use A record instead)
Cannot coexist with other records: If blog.example.com has a CNAME, it cannot have A, MX, or TXT records
Target must be a hostname: Not an IP address
Include trailing dot: example.com. (in raw zone files)

CNAME vs A Record

CNAME	A Record
Points to hostname	Points to IP address
Requires extra DNS lookup	Direct resolution
Easier maintenance	Slightly faster
Cannot be used for root	Can be used anywhere

CNAME Flattening (ALIAS/ANAME)

Some DNS providers offer ALIAS or ANAME records that work like CNAME but for root domains. cPanel does not support this - use A record for root domain instead.

Examples with Third-Party Services

Shopify Custom Domain

www    CNAME    shops.myshopify.com

GitHub Pages

www    CNAME    username.github.io

Cloudflare

cdn    CNAME    example.com.cdn.cloudflare.net

Troubleshooting CNAME

Site not loading: Verify target hostname is correct
SSL errors: Target must support SSL for your domain
Propagation: Wait up to 48 hours for changes

Check CNAME record

nslookup -type=CNAME www.example.com
dig www.example.com CNAME

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