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How to check IP reputation? IP blacklists

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    Sender reputation is complex and dynamic, changing with every IP address and every newsletter sent. It is calculated based on several parameters: sending history, open rate, number of spam complaints, availability of authentication protocols (SPF, DKIM, DMARC), and other criteria.

    If you start to notice that your mailings are getting into spam more and more often, then something is wrong with the reputation of your IP.

    There are several reasons why this is happening. The first thing to look out for is the content of your newsletters. What exactly do you write in emails. Perhaps the content of your emails does not pass spam filters.

    What is IP reputation?

    IP reputation refers to the reputation of an Internet Protocol (IP) address based on its history of sending and receiving emails or engaging in other online activities. An IP address is a unique identifier assigned to a device connected to the internet, and its reputation is determined by various factors such as spam reports, email bounce rates, and blacklists.

    IP reputation is important because many email service providers and other online platforms use reputation scores to determine whether to deliver messages to a recipient’s inbox or classify them as spam. An IP address with a poor reputation may be blocked by email filters or other security measures, preventing legitimate emails from reaching their intended recipients.

    To maintain a good IP reputation, it’s important to follow best practices for email marketing and online behavior. This includes sending emails only to people who have given explicit permission to receive them, avoiding the use of spammy language and tactics, and promptly responding to any complaints or issues that arise.

    If you do not know what is happening, we advise you to use one of the reputation assessment services. Now there are many options for such services, choose whichever you like.

    Their principle of operation is approximately the same. Registration is usually required for verification. It’s very easy to use. Enter the IP address and get a reputation score.

    Notable services: SenderScore, Cisco Talos Intelligence Group, BarracudaCentral and others.

    There is a situation when the service shows that the reputation of your IP is good, but the letters still end up in spam. This is because each email provider has its own algorithms and metrics by which they evaluate your reputation.

    In this case, you need to independently contact the technical support of your mail provider and find out for what reasons your letters end up in spam, and what needs to be done in order to correct this situation.

    What is IP blacklist?

    A blacklist is a list of IP addresses or domains that have been identified as sources of spam, malware, or other malicious activity. Blacklists are used by email service providers, internet service providers, and other organizations to block emails or traffic from these sources, in order to protect their users from potential harm.

    Blacklists are typically maintained by third-party organizations that monitor internet traffic and identify sources of malicious activity. When an IP address or domain is added to a blacklist, emails or traffic originating from that source may be blocked or redirected to spam or junk folders.

    It’s important to note that blacklists are not always accurate or up-to-date, and legitimate sources of traffic or emails may sometimes be blocked by mistake. If you suspect that your IP address or domain has been blacklisted in error, you can contact the blacklist provider or your email or internet service provider to request a removal or delisting.

    The most famous IP blacklists

    ✅ Spamhaus

    Spamhaus maintains a number of blacklists that are widely used to block spam and other unwanted emails. Their lists include the Spamhaus Block List (SBL), the Exploits Block List (XBL), and the Policy Block List (PBL).

    Read also – Spamhaus Zen Blacklist: How To Remove your IP from it


    The SURBL (Spam URI Realtime Blocklist) is a list of domain names that are frequently used in spam emails and other online scams.


    Barracuda Networks maintains a blacklist of IP addresses that have been identified as sources of spam, phishing, and other malicious activity.

    Read also – Barracuda blacklist: How To Remove your IP from it

    ✅ Invaluement

    Invaluement is a community-based blacklist that relies on user submissions and feedback to identify and block spam and other unwanted emails.

    ✅ SpamCop

    SpamCop is a blacklist that provides real-time information about sources of spam and other unwanted emails, and is used by many email service providers to filter incoming messages.

    Read also – SpamCop Blacklist: How To Remove your IP from it

    It’s worth noting that different organizations may use different blacklists or combinations of blacklists to protect their networks and users. If you are experiencing issues with email delivery or internet access, it may be worth checking to see if your IP address or domain is listed on any of these blacklists.

    How to check IP reputation?

    To check the IP reputation, you can use third-party tools and or check your IP in each of the blacklists, this is quite a long time.

    There are several tools available online that allow you to check the reputation of an IP address. Here are a few methods you can use:

    Blacklist Check: you can use a website like MXToolbox or DNSBL to check if your IP address is on any of the major blacklists. These sites will scan multiple blacklists at once and provide a report of any blacklists that list your IP address.

    Sender Score: return Path offers a free tool called Sender Score that provides a reputation score for your IP address based on various factors, including spam complaints, mailing volume, and email engagement.

    Google Postmaster Tools: if you use Google Workspace or Gmail for your email, you can use Google Postmaster Tools to check your IP reputation. This tool provides detailed information about your email delivery performance and reputation, including any issues that may be affecting your email delivery.

    Microsoft SNDS: if you use Microsoft Outlook.com or Exchange Online for your email, you can use the Sender Network Data Service (SNDS) to check your IP reputation. SNDS provides detailed information about your email delivery performance and reputation, and allows you to submit delisting requests if your IP address has been listed on a Microsoft blacklist.

    The second and easier way is to take advantage of our email deliverability service – Warmy. With one simple connection, you can quickly get the inside scoop on your mailbox’s performance – monitoring reputation and whether it is blacklisted. Don’t spend time manually checking each blacklist: let us help save the day!

    In addition, you can see the presence of other technical problems with your email.

    email spam test

    How to remove your IP from IP blacklists?

    If you have identified that your IP address has been added to an IP blacklist, you will need to take steps to have it removed. Here are the general steps you can take to remove your IP from IP blacklists:

    Identify the blacklist

    The first step is to identify which IP blacklists have listed your IP address. You can use a website like MXToolbox or DNSBL to check which blacklists list your IP address.

    Diagnose the issue

    Once you know which blacklists have listed your IP address, you will need to diagnose the issue that caused the listing. This may involve reviewing your email practices, website security, or other factors that could be contributing to the listing.

    Take corrective action

    Once you have identified the issue, take corrective action to address it. This may involve fixing website vulnerabilities, updating email practices, or other measures to improve your IP reputation.

    Request delisting

    After taking corrective action, you can request delisting from each blacklist that has listed your IP address. Most blacklists have a delisting request process that involves filling out a form or sending an email. Be sure to follow the instructions carefully and provide all the required information.

    Monitor your IP reputation

    After requesting delisting, monitor your IP reputation to ensure that your IP address has been removed from the blacklists. You can use the same tools mentioned in the previous question to check your IP reputation regularly.

    It’s important to note that delisting from blacklists may take some time, as each blacklist has its own process and timeframe for delisting requests. Be patient and persistent in your efforts to remove your IP from blacklists, and continue to monitor your IP reputation to ensure that your emails are being delivered successfully.

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