Google is the world's leading search engine and wants to provide its users with a safe online experience. One way to help achieve this goal is to identify potentially harmful websites and blacklist them.
A blacklist is generally used to collect different things that violate certain rules. For website operators, the blacklist kept by Google is of particular interest in the context of search engine optimization (SEO). Google keeps a blacklist for websites and IP addresses that violate search engine guidelines, engage in intensive spamming or violate copyright law or other relevant legal provisions.
Check if your website is blacklisted
How does a website get on Google's blacklist?
Google blacklists websites that may cause security problems or that are in violation of legal requirements such as copyright or search engine policy.
If this is the case, the affected page is removed from the search engine index and can no longer be found in Search Engine Result Pages (SERPs). In most cases, the website operator will be informed about the exclusion. This can either happen via Google Search Console or via email. Browsers that use Google's Blacklist API often generate a red image when accessing a blacklisted domain to warn visitors about potential security problems.
In addition, internet users can report a website to Google that appears suspicious to them. Google then checks the reported domain, removes it from its index if the suspicion is confirmed and adds it to its blacklist.
How can I determine whether a page has been blacklisted?
A simple way to do an initial check is to query the site on Google. If a site query (e.g. site:example.com) does not list any pages, although this was the case a short time ago, this is an indication that the pages have been removed from the index.
In addition, with Search Console, Google offers webmasters numerous analysis tools for their websites. If security problems occur, administrators receive a direct message via Google Search Console. Webmasters can also find a tool to check whether one or more websites have been removed from the index for copyright infringement at www.google.com/transparencyreport/removals/copyright. In addition, there are several free tools available on the internet to find out if your domain is blacklisted.
If your domain has been blacklisted and you want Google to add it to its index again, you have to submit a reconsideration request. Prerequisite is that you removed all critical content and fixed all security problems on your website. You should justify your request with as many details as possible in order to facilitate the work of the employees at Google and thus speed up the whole process. Depending on the amount of work involved, it may take between one and five days for a website to reappear in Google’s index.
Other types of blacklists
Several organizations specialize in managing and publishing blacklists of IP addresses and URLs of systems and networks suspected of spreading malware and causing security problems. Many of these lists are publicly accessible and free to use, but some have usage restrictions.
Google also warns its users about websites that are affected by malware. If malware is found on a website, search engine users are shown a warning such as "This site may harm your computer".
Content Management Systems (CMS) allow users to create their own content-blacklists to prevent certain unwanted content from being displayed, for example in comments published by users. The simplest form of a content blacklist is a word filter.
Another type of blacklist that is particularly relevant for email marketing is email-blacklists. These are usually publicly accessible and contain domains and/or IP addresses that distribute spam emails or are suspected of doing so. The domains or IP addresses in question are blocked by the email provider and e-mails sent from these sources are intercepted. Since different email providers (Gmail, GMX, etc.) use different blacklists, a domain that is on one of those lists is not necessarily blocked by all providers.