Published on 2025-08-07T06:18:08Z

ia_archiver

iaarchiver is the primary web crawler for the Internet Archive, the non-profit digital library best known for its Wayback Machine. Its mission is to capture and preserve public web pages for historical purposes. Unlike search engine crawlers, which index current content, iaarchiver creates a historical record, offering a free, de facto backup service that can preserve a website's content even if it later goes offline.

What is ia_archiver?

ia_archiver is the official web crawler for the Internet Archive, the non-profit organization that runs the Wayback Machine. This crawler's function is to systematically visit websites and capture snapshots of their pages for preservation. It identifies itself in server logs with the user-agent string ia_archiver. Its primary concern is creating a historical record, so it attempts to capture a complete page rendering, including text and layout. However, its ability to process dynamic elements like JavaScript is limited, so archived pages may not always perfectly reflect the original's functionality.

Why is ia_archiver crawling my site?

The ia_archiver bot is visiting your website to create a historical snapshot for the Internet Archive's Wayback Machine. It prioritizes publicly accessible pages, especially those with perceived historical or cultural significance. The crawl frequency varies based on a site's visibility and update schedule; high-traffic sites may be visited weekly, while others might be crawled quarterly. This activity is part of the Internet Archive's mission to create a comprehensive digital library and is considered a legitimate archival activity.

What is the purpose of ia_archiver?

The purpose of ia_archiver is to support the Internet Archive's mission of building a digital library of internet sites and cultural artifacts. The content it collects serves several important functions, including the historical preservation of web content, providing researchers and the public with access to past versions of websites, and serving as evidence in legal contexts. For website owners, this provides a free backup service that preserves your content even if your site experiences data loss or goes offline, making your work accessible to future generations through the Wayback Machine.

How do I block ia_archiver?

While the work of the Internet Archive is considered a public good, you can opt out of having your site archived. To prevent ia_archiver from crawling your site, you can add a rule to your robots.txt file.

To block this crawler, add the following lines to your robots.txt file:

User-agent: ia_archiver
Disallow: /

How to verify the authenticity of the user-agent operated by Internet Archive?

Reverse IP lookup technique

To verify user-agent authenticity, you can use host linux command two times with the IP address of the requester.

```
> host IPAddressOfRequest
```
This command returns the reverse lookup hostname (e.g., 4.4.8.8.in-addr.arpa.).

> host ReverseDNSFromTheOutputOfFirstRequest

If the output matches the original IP address and the domain is associated with a trusted operator (e.g., Internet Archive), the user-agent can be considered legitimate.

IP list lookup technique

Some operators provide a public list of IP addresses used by their crawlers. This list can be cross-referenced to verify a user-agent's authenticity. However, both operators and website owners may find it challenging to maintain an up-to-date list, so use this method with caution and in conjunction with other verification techniques.