Published: 12.06.2026
Every device on the internet has an address that lets others find it. For websites this address is the IP address of the server. Knowing how it works clears up many questions about DNS, e-mail delivery and certificates.
What an IP address is
An IP address is a number that identifies a device or a server on a network. Computers talk to each other with numbers, and domain names exist only to make addresses easy for people. When you open a site, DNS translates the domain into the IP address of the server.
IPv4 and IPv6
IPv4 addresses look like 203.0.113.10: four numbers from 0 to 255. There are only about four billion of them, and they have run out in many regions. IPv6 addresses are longer, such as 2001:db8::1, and there are practically unlimited numbers of them. Most modern networks use both, and a good website supports both with A and AAAA records.
Shared and dedicated IP
On shared hosting many websites often use the same server IP address. The server knows which site to show from the name requested by the browser. A dedicated IP is an address used only by your account or your server.
When a dedicated IP is useful
- E-mail reputation. If you send a lot of mail, your own address means other users cannot damage its reputation.
- Access by IP. Some services require a fixed address in an allow-list, for example for payment gateways or APIs.
- Older software. Some old clients or devices do not support certificates for many names on one address.
- Firewall rules. A fixed address makes it simpler to open access for your office to the admin panel.
- Dedicated servers and VPS. They normally have their own addresses by default.
When you do not need one
For a normal website, a shared IP is enough. Modern HTTPS supports many certificates on one address, and search engines do not rank a site higher because of a dedicated IP. It has no direct effect on SEO.
Reverse DNS
A PTR record maps an IP address back to a name. Mail servers check it, and a mismatch between the sending IP, the PTR name and the mail server name makes messages more likely to be marked as spam. On a VPS you can usually set it in the client area.
Check your own address
- Use a lookup tool for the domain to see the A and AAAA records.
- Check the address on blocklist services if mail is not delivered.
- Find the geographic location of the address to see which region your server appears to be in.
Changing the IP address of a site
When you move a site, you change the A record to the new address. Lower the TTL a day before the change so that the new address spreads quickly, and keep the old server running for a few days.
Security and the IP address
Hiding the real server IP behind a proxy or a CDN makes direct attacks harder. Once the address is public, restrict direct access with a firewall so that only the proxy can connect.
Frequently asked questions
Can an IP address change? Yes, if you change the server or if the provider assigns a different one. A fixed address is normally included in a VPS.
Does a dedicated IP make a site faster? No. Speed depends on resources, not on the address.
Do I need a dedicated IP for SSL? No. Modern browsers support certificates on shared addresses.
