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How HTTP status codes, and network and DNS errors affect Google Search

This page describes how different HTTP status codes, network errors, and DNS errors affect Google Search. We cover the top 20 status codes that Googlebot encountered on the web, and the most prominent network and DNS errors. More exotic status codes, such as 418 (I'm a teapot), aren't covered. All issues mentioned on this page generate a corresponding error or warning in Search Console's Index Coverage report.

HTTP status codes

HTTP status codes are generated by the server that's hosting the site when it responds to a request made by a client, for example a browser or a crawler. Every HTTP status code has a different meaning, but often the outcome of the request is the same. For example, there are multiple status codes that signal redirection, but their outcome is the same.

Search Console generates error messages for status codes in the 4xx–5xx range, and for failed redirections (3xx). If the server responded with a 2xx status code, the content received in the response may be considered for indexing.

HTTP status codes

2xx (success)

Google considers the content for indexing. If the content suggests an error, for example an empty page or an error message, Search Console will show a soft 404 error.

200 (success)

Google passes on the content to the indexing pipeline. The indexing systems may index the content, but that's not guaranteed.

201 (created)
202 (accepted)

Googlebot waits for the content for a limited time, then passes on whatever it received to the indexing pipeline. The timeout is user agent dependent, for example Googlebot Smartphone may have a different timeout than Googlebot Image.

204 (no content)

Googlebot signals the indexing pipeline that it received no content. Search Console may show a soft 404 error in the site's Index Coverage report.

3xx (redirection)

Googlebot follows up to 10 redirect hops. If the crawler doesn't receive content within 10 hops, Search Console will show a redirect error in the site's Index Coverage report. The number of hops Googlebot follows is user agent dependent; for example, Googlebot Smartphone may have a different value than Googlebot Image.

In case of robots.txt, Googlebot follows at least five redirect hops as defined by RFC 1945 and then stops and treats it as a 404 for the robots.txt file.

Any content Googlebot received from the redirecting URL is ignored, and the final target URL's content is considered for indexing.

301 (moved permanently)

Googlebot follows the redirect, and the indexing pipeline uses the redirect as a strong signal that the redirect target should be canonical.

302 (found)

Googlebot follows the redirect, and the indexing pipeline uses the redirect as a weak signal that the redirect target should be canonical.

303 (see other)
304 (not modified)

Googlebot signals the indexing pipeline that the content is the same as last time it was crawled. The indexing pipeline may recalculate signals for the URL, but otherwise the status code has no effect on indexing.

307 (temporary redirect) Equivalent to 302.
308 (moved permanently) Equivalent to 301.

4xx (client errors)

Google's indexing pipeline doesn't consider URLs that return a 4xx status code for indexing, and URLs that are already indexed and return a 4xx status code are removed from the index.

Any content Googlebot received from URLs that return a 4xx status code is ignored.

400 (bad request)

All 4xx errors, except 429, are treated the same: Googlebot signals the indexing pipeline that the content doesn't exist.

The indexing pipeline removes the URL from the index if it was previously indexed. Newly encountered 404 pages aren't processed. The crawling frequency gradually decreases.

401 (unauthorized)
403 (forbidden)
404 (not found)
410 (gone)
411 (length required)
429 (too many requests)

Googlebot treats the 429 status code as a signal that the server is overloaded, and it's considered a server error.

5xx (server errors)

5xx and 429 server errors prompt Google's crawlers to temporarily slow down with crawling. Already indexed URLs are preserved in the index, but eventually dropped.

If the robots.txt file returns a server error status code for more than 30 days, Google will use the last cached copy of the robots.txt. If unavailable, Google assumes that there are no crawl restrictions.

Any content Googlebot received from URLs that return a 5xx status code is ignored.

500 (internal server error)

Googlebot decreases the crawl rate for the site. The decrease in crawl rate is proportionate to the number of individual URLs that are returning a server error. Google's indexing pipeline removes from the index URLs that persistently return a server error.

502 (bad gateway)
503 (service unavailable)

soft 404 errors

A soft 404 error is when a URL that returns a page telling the user that the page does not exist and also a 200 (success) status code. In some cases, it might be a page with no main content or empty page.

Such pages may be generated for various reasons by your website's web server or content management system, or the user's browser. For example:

  • A missing server-side include file.
  • A broken connection to the database.
  • An empty internal search result page.
  • An unloaded or otherwise missing JavaScript file.

It's a bad user experience to return a 200 (success) status code, but then display or suggest an error message or some kind of error on the page. Users may think the page is a live working page, but then are presented with some kind of error. Such pages are excluded from Search.

When Google's algorithms detect that the page is actually an error page based on its content, Search Console will show a soft 404 error in the site's Index Coverage report.

Fix soft 404 errors

Depending on the state of the page and the desired outcome, you can solve soft 404 errors in multiple ways:

Try to determine which solution would be the best for your users.

The page and content are no longer available

If you removed the page and there's no replacement page on your site with similar content, return a 404 (not found) or 410 (gone) response (status) code for the page. These status codes indicate to search engines that the page doesn't exist and the content should not be indexed.

If you have access to your server's configuration files, you can make these error pages useful to users by customizing them. A good custom 404 page helps people find the information they're looking for, and also provides other helpful content that encourages people to explore your site further. Here are some tips for designing a useful custom 404 page:

  • Tell visitors clearly that the page they're looking for can't be found. Use language that is friendly and inviting.
  • Make sure your 404 page has the same look and feel (including navigation) as the rest of your site.
  • Consider adding links to your most popular articles or posts, as well as a link to your site's home page.
  • Think about providing a way for users to report a broken link.

Custom 404 pages are created solely for users. Since these pages are useless from a search engine's perspective, make sure the server returns a 404 HTTP status code to prevent having the pages indexed.

The page or content is now somewhere else

If your page has moved or has a clear replacement on your site, return a 301 (permanent redirect) to redirect the user. This will not interrupt their browsing experience and it's also a great way to tell search engines about the new location of the page. Use the URL Inspection tool to verify whether your URL is actually returning the correct code.

The page and content still exist

If an otherwise good page was flagged with a soft 404 error, it's likely it didn't load properly for Googlebot, it was missing critical resources, or it displayed a prominent error message during rendering. Use the URL Inspection tool to examine the rendered content and the returned HTTP code. If the rendered page is blank, nearly blank, or the content has an error message, it could be that your page references many resources that can't be loaded (images, scripts, and other non-textual elements), which can be interpreted as a soft 404. Reasons that resources can't be loaded include blocked resources (blocked by robots.txt), having too many resources on a page, various server errors, or slow loading or very large resources.

Network and DNS errors

Network and DNS errors have quick, negative effects on a URL's presence in Google Search. Googlebot treats network timeouts, connection reset, and DNS errors similarly to 5xx server errors. In case of network errors, crawling immediately starts slowing down, as a network error is a sign that the server may not be able to handle the serving load. Since Googlebot couldn't reach the server hosting the site, Google also hasn't received any content from the server. The lack of content means that Google can't index the crawled URLs, and already indexed URLs that are unreachable will be removed from Google's index within days. Search Console may generate errors for each respective error.

Debug network errors

These errors happen before Google starts crawling a URL or while Google is crawling the URL. Since the errors may occur before the server can respond and so there's no status code that can hint at issues, diagnosing these errors can be more challenging. To debug timeout and connection reset errors:

  • Look at your firewall settings and logs. There may be an overly-broad blocking rule set. Make sure that Googlebot IP addresses are not blocked by any firewall rule.
  • Look at the network traffic. Use tools like tcpdump and Wireshark to capture and analyze TCP packets, and look for anomalies that point to a specific network component or server module.
  • If you can't find anything suspicious, contact your hosting company.

The error may be in any server component that handles network traffic. For example, overloaded network interfaces may drop packets leading to timeouts (inability to establish a connection) and reset connections (RST packet sent because a port was mistakenly closed).

Debug DNS errors

DNS errors are most commonly caused by misconfiguration, but they may be also caused by a firewall rule that's blocking Googlebot DNS queries. To debug DNS errors, do the following:

  • Inspect your firewall rules. Make sure that none of Google's IPs are blocked by any firewall rule, and that both UDP and TCP requests are allowed.
  • Look at your DNS records. Double check that your A and CNAME records are pointing to the right IP addresses and hostname, respectively. For example:
    dig +nocmd example.com a +noall +answer
    dig +nocmd www.example.com cname +noall +answer
  • Check that all your name servers are pointing to the correct IP addresses of your site. For example:
    dig +nocmd example.com ns +noall +answer
    example.com.    86400  IN  NS  a.iana-servers.net.
    example.com.    86400  IN  NS  b.iana-servers.net.
    dig +nocmd @a.iana-servers.net example.com +noall +answer
    example.com.    86400  IN  A  93.184.216.34
    dig +nocmd @b.iana-servers.net example.com +noall +answer
    ...
  • If you've made changes to your DNS configuration within the last 72 hours, you may need to wait for your changes to propagate across the global DNS network. To speed up propagation, you can flush Google's Public DNS cache.
  • If you're running your own DNS server, make sure it's healthy and that it's not overloaded.