# What are ISPs and ASNs

An ISP is the company that connects a visitor to the internet. An ASN identifies the network an IP address belongs to, like an ISP, a data center or a hosting provider. Both help tell real visitors from automated traffic.

Source: https://www.clickguard.com/help/glossary/what-are-isps-and-asns
Published: 2026-10-11
Updated: 2026-10-11
Author: Nikola Pejic

Every visitor reaches your website through a network. The ISP and the ASN tell you whose network it is, which helps tell real visitors from automated traffic.

## ISP

An ISP (Internet Service Provider) is the company that connects a visitor to the internet, like a home broadband or mobile carrier. Most real visitors browse from a residential or mobile ISP.

## ASN

An ASN (Autonomous System Number) is a number that identifies a network run by a single organization. That organization can be an ISP, but also a data center, a cloud or hosting provider, or a large company. Every [IP address](https://www.clickguard.com/help/glossary/what-are-ips-and-ip-ranges) belongs to an ASN.

## Why they matter for click fraud

Bots and click farms often run from data centers, hosting providers and VPN networks rather than from home or mobile connections. When many bad clicks share the same ISP or ASN, that network is likely a source of invalid traffic.

## Blocking an ISP or ASN

If you need to, you can create a custom rule in ClickGuard to block a specific ISP or ASN. Add other triggers to the rule to make it more precise, so you only block the traffic that matches all of them and not every visitor on that network.

Be careful with large residential or mobile ISPs: many of your real customers use them, so blocking one entirely can stop real people from seeing your ads.

## Related articles

- [What are IPs and IP ranges](https://www.clickguard.com/help/glossary/what-are-ips-and-ip-ranges.md)