DNS is the internet’s phone book: it looks up a domain name, such as yourcompany.com, and tells browsers which computer holds that website. Without it, visitors would have to type a string of numbers instead of your name.
What is DNS?
DNS stands for Domain Name System. It also tells the world where email for your domain should be delivered, which makes a wrong setting more costly than it looks.
Think of DNS as a phone book that every browser consults. When someone types your domain nameA domain name is the address people type to reach your website, such as yourcompany.com. It points visitors to wherever your site is hosted., their device asks a DNS server for the address behind it. The answer comes from the DNS records you or your provider have set up for the domain, and the device then connects to that address.
Records come in types. An A record points a name to an IPv4 address and an AAAA record does the same for IPv6. A CNAME record makes one name an alias of another. An MX record tells mail servers where to deliver email, and a TXT record holds text such as verification codes and email authentication settings. Every record has a TTL, the time other systems may keep the answer before asking again.
What DNS means for a PHP or WordPress site
DNS decides which server receives the visitors. That makes it the switch you flip during a migration: you build the new site on the new server, test it, and then change the A record to the new address. Until the old answers have expired everywhere, some visitors still reach the old server.
Because of that delay, a careful move lowers the TTL a day or so beforehand, so the change spreads quickly, and keeps the old server running for a while after the switch. It also means that your web hostingWeb hosting is the service that keeps your website's files on a computer that is always online, so visitors can open your site at any time. provider and your DNS provider can be two different companies. Moving the site does not require moving the DNS, and moving the DNS does not require moving the site.
Email is the part people forget. Overwriting the whole zone with the new host’s defaults can delete the MX and TXT records, and email stops. Copy the existing records first.
If you use a CDNA CDN is a network of servers around the world that keeps copies of your website close to your visitors, so pages load fast wherever they are. in front of the site, the DNS settings often point to the CDN rather than directly to your server.
How to check a DNS record
Tools such as dig or nslookup in a terminal, and many free websites, show the current records for a name. Look at the A or CNAME record for the site, the MX records for email and the TTL. Compare what you see with what your hosting provider tells you the address should be.
When to act
Check DNS whenever the site shows the wrong server, a certificate warning appears after a move, or email stops arriving. Plan it before any switch of host or rebuild. Our PHP migration service includes the DNS step, and when you move from WordPress to a static site, the same care applies when the name is pointed at the new static hosting.
Frequently asked questions
What is a DNS record?
A DNS record is one entry in the settings of your domain. Each has a type, a name and a value. For example an A record points a name to a server address, and an MX record says where email for the domain goes.
How long does a DNS change take?
It depends on the TTL (time to live) of the old record, which sets how long others may keep the previous answer. The change can be visible within minutes for some visitors and take longer for others, so plan around that.
Why does my site show the old server after a move?
Some networks and devices still hold the old DNS answer until its TTL runs out. Wait for the TTL period, clear your own device's cacheA cache is a store of ready-made copies, such as finished pages, so a website or browser can show something instantly instead of building it again. and check the result from another network before you assume something is broken.