IP Addresses and Networking
An IP address identifies a network destination. Website DNS commonly points a hostname to an IPv4 address with an A record or an IPv6 address with an AAAA record. Read DNS, Nameservers and Caching for the relationship between domains and addresses.
Not every visible address is the web server
Shared hosting can serve several websites from one IP address. A content delivery network or reverse proxy can also place its own addresses in front of the hosting server, so a public DNS lookup may not reveal the origin server’s address. Use the destination supplied by your host or service provider rather than copying an address from an unrelated lookup.
When an IP address is used
- Pointing a domain to hosting with an A or AAAA record.
- Allowing a trusted connection through a hosting firewall.
- Restricting administrative services such as SFTP, SSH or remote database access.
- Checking whether traffic is reaching a CDN, proxy or origin server.
Before allowing or blocking an address
Confirm whether the address is fixed or may change. Home and mobile connections often use dynamic addresses, while several people can appear under one shared address. Review logs and the time of the activity before applying a block. For unwanted website traffic, see Blocking Visitors.
Common questions
Frequently Asked Questions
What is the difference between IPv4 and IPv6?
They are different address formats. IPv4 addresses look like 192.0.2.10, while IPv6 uses a longer hexadecimal format. A website can publish either or both when its hosting supports them.
Can several websites use the same IP address?
Yes. Shared hosting and proxy services commonly serve many domains from the same address.
Why does my domain show a Cloudflare address instead of my hosting address?
A proxied Cloudflare record returns Cloudflare network addresses publicly while Cloudflare sends valid website traffic to the origin server.
Why did an allowlisted address stop working?
The connecting device may have received a new public IP address, or the traffic may now pass through a different network or proxy. Check the current address and the relevant access logs.