What to do if Semonto could not monitor your website

Does Semonto return an HTTP 403 status code or the message “Blocked by robots.txt” when you are trying to monitor your website? This is what you can do about it.

Screenshot of blocked broken link check in Semonto

Semonto visits the pages of your website to check whether they are accessible and functioning as they should. To do this, our software frequently connects to your server and uses techniques like crawling to run tests and detect issues like broken links. But if your website refuses to let our software in, we cannot monitor your website. Let’s discuss the different possible causes so that you can find a way to fix your situation.

Possibility 1: Semonto is blocked by a firewall

If you have a firewall, it could be possible that your firewall is blocking traffic from Semonto to your website. Please ensure our Semonto IP addresses can connect to your server. You can test the connection from Semonto to your website by using our free reachabilty test.

Below is the list of IP addresses used by Semonto in multiple formats:

Possibility 2: Semonto is blocked by robots.txt

As a website owner, you can control which information on your website is indexed by search engines like Google. There can be certain pages that you do not want not appear in the search results. For example: pages with very little content or with sensitive information. One way to tell crawlers to ignore a part of your website is by using a robots.txt file. That is a simple text file that tells the web crawlerwhich parts of the site it is allowed to visit and which parts it should avoid. The problem is that not only search engines use crawlers. Website monitors use them too. So if you close the door for our crawlers, we cannot monitor your pages and Semonto will return “Blocked by robots.txt”.

Blocked crawler in Semonto

How does robots.txt work?
Our crawler will first read your robots.txt to see whether it is allowed to visit your website. The robots.txt rules contain two parts:

  • User-agent: which crawler you are defining a rule for
  • Disallow: which parts of the website the crawler is not allowed to visit

For example, if you do not want Googlebot to crawl your private folder, you could put this in your robots.txt:

  • User-agent: Googlebot
  • Disallow: /private/

Read more about robots.txt syntax here.

Why does Semonto get blocked by robots.txt?
If Semonto is being blocked, chances are that you have blocked all crawlers. That would look something like this in your robots.txt file:

  • User-agent: *

This * means that you are blocking every robot.

Also, make sure to check what is being mentioned in the Disallow-field, because those pages or folders will possibly be skipped by Semonto and could affect your results.

Where can I see my robots.txt file?
Open your browser and type your URL, followed by /robots.txt. If you have a robots.txt file, it will appear. For example, the robots.txt file for Semonto is https://semonto.com/robots.txt

Blocked crawler in Semonto

How to fix it
Changing the robots.txt file is usually done by your web developer. Ask them for assistance, or feel free to reach out to us for help.

There are 2 fixes you can try:

  • 1. Delete the existing rule altogether, if you want to allow all crawlers from now on.
  • 2. Add another rule and place it before the existing rule. The rule should specify Semonto as an allowed user-agent and leave the Disallow-field empty:
User-agent: Semonto

With this rule you are saying that Semonto is allowed to visit all pages of your website.

Possibility 3: status code HTTP 403

If Semonto did not get blocked by the robots.txt file, it will go on to check the status of your website. It does so by requesting the first page and then checking the returned status code. A status code is a message that your server sends to your browser to explain if your request was successful. You are probably familiar with the most common status codes:

  • HTTP 200 means that everything is OK.
  • HTTP 404 means that the requested resource could not be found.

HTTP 403 means “Access forbidden”. This code indicates that we do not have permission to visit the resource. Semonto can return this message for an entire website or for a specific page. The message is the same in both cases: “We were not allowed to go there.”

Read more about the most common status codes here.

What are the probable causes?

  • Log-in required: On some websites, you need a login and password in order to visit certain pages. Since Semonto cannot log in for you, it is normal that you get an HTTP 403 for those pages. If you do not want to be notified of those pages in the future, you can simply hit the “ignore” button in the broken links results.
  • IP limitations: As explained in the first possibility, you can restrict access to some parts of your website to the entire website, based on the IP address or even user-agent of the requester.
The ignore option in Semonto

Possibility 4: blocked by Cloudflare

Sometimes an HTTP 403 is caused by strict page rules settings in Cloudflare, a Content Delivery Network. We have addressed this issue in a separate article about Cloudflare.

Possibility 5: blocked by robots metatags

In the same way a robots.txt file can tell crawlers that they are not allowed (see earlier in this article), robots metatags can also be used. While a robot.txt file is placed in the root directory of a website, robots meta tags are HTML elements that are placed within the

section of individual web pages. They provide instructions specific to the page on which they are placed, overriding any conflicting rules in the robots.txt file.They are used for more detailed instructions, allowing you to specify how a single page should be treated by web crawlers.

Signs that Semonto is being blocked by robots metatags

  • If you are using Semonto to scan your website for broken links and the results are incomplete, that could mean that we have skipped certain pages because we were not allowed to scan them. In that case: check the robot metatags for that page and edit them if needed. For example: your website has 200 pages and Semonto only scanned 198 pages.
  • If Semonto does not report a known broken link, chances are that you have blocked Semonto from that page. If we are not allowed to scan a page, we cannot notify you of any broken links on that page. Solution: check the robots metatags for that page and edit them if needed.

Why does Semonto get blocked by robots metatags?
If Semonto is being blocked, chances are that you have blocked all crawlers. That would look something like this in your robots.txt metatags:

<meta name="robots" content="noindex, nofollow">

How can I fix it?
Delete the robots metatags or change them to “index, follow”.

Let us know if you need any help

Have you found what you were looking for in this article? If not, feel free to reach out. We love to help you with any issue you are running into.