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Checking Whether W2's WAF Is Blocking Crawlers

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Checking Whether W2's WAF Is Blocking Crawlers

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Guides
Read Time
6 min read
Topic
Japan EC platform guides for search and AI search

On a self-operated platform like W2, the WAF, bot protection, or rate limiting can block search engine and AI crawlers by accident. This article lays out the steps for checking whether crawlers are blocked using Search Console and server logs, how to tell legitimate crawlers apart, and how to decide whether to allow or refuse AI crawlers.

Source
searchos.io/en/blog
Copyright
© 2026 Search OS

On a site run on W2, the indexed count suddenly dropped one week. Nothing changed on the site side, but around that time the WAF settings were changed as part of a security hardening. Shops operating on their own platform raise this.

The first suspect is the WAF or bot protection. A crawler is a program that reads through pages. The WAF may be judging search engine and AI crawlers as hostile bots. A crawler judged that way is blocked outright. Crawlers send many requests in a short time, so they're prone to tripping rate limits and behavior detection. When blocked, Googlebot receives errors (403, 429, 5xx). The indexed count falls and rankings drop. The site's HTML hasn't changed at all, so the cause stays hard to notice.

This article lays out the steps for confirming a block and how to tell legitimate crawlers apart. It also covers the policy for allowing or refusing AI crawlers and the operating rules for changing settings.

Conclusion: Check Search Console crawl stats and server log response codes, and put legitimate crawlers on the allow list

Check

Where to look

Signs of blocking

Crawl responses

Search Console Settings → Crawl stats

Share of 403, 429, and 5xx rising

Fetch success

Search Console URL Inspection → Live test

"Could not be fetched"

Server logs

WAF and web server logs

403 and 429 against User-Agents such as Googlebot and GPTBot

WAF block logs

WAF admin console

Legitimate crawler IPs appear among blocked targets

Check whether the WAF blocks crawlers

Metadata

  • Search OS
  • Guide 01

Check whether the WAF blocks crawlers

Suspect it when 403, 429 and 5xx rise

StepDescription
Crawl statsSearch Console settings response code breakdown
Live URL inspection"Could not fetch" means it is blocked
Server logs403 and 429 sent to Googlebot and GPTBot
WAF block logAre real crawler IPs among those blocked?
Update allowlistVerify with published IP ranges robots.txt denial is separate
POINT
A WAF change is a site change log the date and compare with indexing

© 2026 Search OS

Key idea: A WAF settings change is a site change. Even if you didn't touch the HTML, the site as search engines see it has changed. Record the date of each settings change so you can compare it against changes in indexing. Start by writing down the most recent date the WAF was changed.

Step 1: Check in Search Console

  1. Open Settings → Crawl stats

  2. Check whether "Host status" shows a problem

  3. In the "By response" breakdown, identify when 403, 429, and 5xx rose

  4. Run a live test on core pages in URL Inspection and confirm they can be fetched

If the live test can't fetch, Googlebot is blocked at that point. Run your core pages through the live test.

Step 2: Check server logs

Filter the WAF or web server access log on the following conditions.

  • User-Agent contains Googlebot, bingbot, GPTBot, ClaudeBot, PerplexityBot, or similar

  • Response code is 403, 429, or 5xx

If there are hits, use the WAF log to pin down which rule blocked them. First, check the response codes sent to Googlebot in the log.

Step 3: Tell legitimate crawlers apart

User-Agent can be spoofed. Combine the allow list with IP verification.

Crawler

Verification method

Googlebot

Match against Google's published IP address ranges (JSON), or confirm googlebot.com by reverse DNS

bingbot

Match against Bing's published IP ranges

GPTBot and OAI-SearchBot

Match against OpenAI's published IP ranges

ClaudeBot

Match against the information Anthropic publishes

PerplexityBot

Match against Perplexity's published IP ranges

Each company's published IPs get updated. Review the allow list regularly too. Compare Googlebot's published IP ranges against your allow list.

Allow or refuse AI crawlers

This is a matter of policy, not technology.

Policy

Meaning

Setting

Allow both search engines and AI

Aim for citations in AI search

All legitimate crawlers on the allow list

Allow search engines, refuse AI training, allow AI search

Want citations but not use for training

Refuse GPTBot (training), allow OAI-SearchBot (search), and so on

Allow search engines only

Don't need to appear in AI search

Refuse AI crawlers in robots.txt

Allow or block AI crawlers

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  • Search OS
  • Guide 02

Allow or block AI crawlers

A policy question, not a technical one

numbertitledescription
1Allow search engines and AIAim for AI search citations → allowlist all verified crawlers
2Block training, allow searchWant citations, not training → block GPTBot, allow OAI-SearchBot
3Allow search engines onlyFine without AI search → block AI crawlers in robots.txt

© 2026 Search OS

If you refuse, the basic rule is to do it in robots.txt, not the WAF. Block with the WAF and the crawler records it as an error. That can affect how the site's health is assessed. A refusal in robots.txt is treated as intentional. Confirm that the bots you want to refuse are listed in robots.txt.

Operating rules for settings changes

  • Record the date and content of every change to WAF, bot protection, and rate limiting settings

  • For a week after a change, check response codes in Search Console crawl stats

  • Before updating the allow list, fetch each company's latest IP ranges

  • Set the rate limit threshold no lower than Googlebot's normal crawl frequency (check it in crawl stats)

Operation after the check

The security team changes WAF settings and the SEO owner doesn't know. It's a common situation. Even if one check finds no problem, the next settings change causes it again. New AI crawlers keep appearing too, so the assumptions behind the allow list keep shifting.

Search OS is a layer that supports self-operated platforms such as W2. From bot logs, it continuously monitors response codes for search engine and AI crawlers. It finds blocks as they occur, new crawlers as they appear, and gaps between the allow list and reality, and organizes them into items to fix. It isn't the layer that configures the WAF. It's a layer that keeps watching what happens to crawlers as a result of the configuration. Start by making it a rule that whoever changes the WAF tells the SEO owner.

Frequently asked questions

Does even a temporary block affect indexing?

A block of a few days recovers once lifted. If it lasts weeks, pages start dropping out of the index. Recovery then takes time.

Is there bot protection on the CDN side too?

CDNs have bot protection as well. Sometimes it's blocking in tandem with the WAF. Look at the CDN logs too.

Isn't tripping the rate limit a sign that Googlebot crawls too much?

Search Console used to have a setting to lower Googlebot's crawl rate. Now there's only automatic adjustment. If the site is slow or returns many errors, crawling decreases on its own. Stabilizing the site's responses is more reliable than refusing through rate limits.

Related reading

References

The site becomes easier to read

The content becomes clearer

The brand gets discovered in more customer questions

See how Search OS works, starting with the product deck.