This article explains what DNS is, how the lookup process works, what the most common DNS record types do, and how DNS propagation affects your website. Whether you are setting up a new domain or troubleshooting an issue, this knowledge gives you the foundation you need.

DNS stands for Domain Name System. Think of it as the internet's phone book. When you type example.com into your browser, your computer does not know where that website lives. It needs a numeric IP address (like 93.184.216.34) to connect to the right server.

DNS is the system that performs this translation. It takes the domain name you type and returns the correct IP address so your browser can load the website. This lookup happens in milliseconds, behind the scenes, every time you visit a website.

When you enter a domain name in your browser, the following happens in order:

1. Browser cache — your browser checks if it has recently looked up this domain. If so, it uses the cached result.
2. Operating system cache — if the browser does not have it, the OS checks its own DNS cache.
3. Recursive resolver — if neither cache has the answer, the request goes to a DNS resolver (typically provided by your ISP or a service like Google DNS 8.8.8.8).
4. Root nameserver — the resolver asks a root nameserver, which directs it to the TLD nameserver (e.g. the .com nameserver).
5. TLD nameserver — the TLD nameserver points to the domain's authoritative nameserver (e.g. ns1.hostdog.gr).
6. Authoritative nameserver — this server holds the actual DNS records for the domain and returns the IP address.
7. Connection established — your browser connects to the IP address and loads the website.

This entire process typically takes less than 100 milliseconds. Results are cached at multiple levels to speed up future lookups.

DNS records are instructions stored on the authoritative nameserver that tell the internet how to handle requests for your domain. Here are the most common types:

To manage these records for domains hosted at HOSTDOG, see How to manage DNS records (A, CNAME, MX, TXT).

Nameservers are the servers that hold your domain's DNS records and respond to DNS queries. When you register a domain and point it to HOSTDOG, you set the nameservers to:

• ns1.hostdog.gr
• ns2.hostdog.gr

This tells the internet that HOSTDOG's nameservers are authoritative for your domain — meaning they hold the master copy of your DNS records (A, MX, CNAME, TXT, etc.).

For more details, see What are HOSTDOG's nameservers? and How to change your domain's nameservers.

When you change a DNS record (or switch nameservers), the update does not take effect instantly worldwide. DNS caches at every level — from your browser to ISP resolvers — need time to expire and fetch the new information. This process is called DNS propagation.

Propagation times depend on the record's TTL (Time to Live) value, which tells resolvers how long to cache the record. Typical propagation times:

• Minor record changes (e.g. updating an A record value) — usually 1–4 hours
• Nameserver changes — up to 24–48 hours in the worst case, though often faster

DNS affects nearly everything about how your online presence functions:

• Website accessibility — incorrect A records or nameservers mean your site cannot be found
• Email delivery — MX records determine where emails are routed. Misconfigured MX records cause undelivered email.
• Email authentication — TXT records hold SPF, DKIM, and DMARC policies that prevent your emails from being marked as spam
• Domain verification — services like Google Search Console and analytics platforms use TXT records to verify domain ownership
• Security — DNSSEC and CAA records add layers of protection against spoofing and unauthorized certificate issuance

• How to manage DNS records (A, CNAME, MX, TXT)
• How to change your domain's nameservers
• What are HOSTDOG's nameservers (DNS)?
• How to point your domain to HOSTDOG