7 Best IP Reputation Checkers for Email in 2024

Not getting the delivery rates you want from your email marketing campaigns? Too many messages landing in spam? It’s time to check your IP reputation.

IP reputation is how the receiving email server judges how trustworthy a sender you are. A poor IP reputation means spam filters will block more of your messages and send them to the spam folder.

But how do you avoid this? Your first call is to understand what spam filters see when you send a message. That’s what an IP reputation checker does.

IP reputation checkers can make a big difference to your email deliverability rates. In this article, I’ll walk you through what they do and how they help. And I’ll also review and compare some of the best IP reputation checkers.

7 Best IP Reputation Checker Tools Overview

If all this talk about having a bad IP reputation sounds technical and scary, don’t worry. IP reputation checkers make it simple. They look at the same data spam filters use to accept or reject emails. And then tell you how you’re shaping up.

Brands use IP reputation checker tools to get to the bottom of poor deliverability and improve IP reputation. You also want to spot issues before you send a campaign, monitoring to get the best chance of success. 

Different IP reputation checkers work in different ways. Which one is right for the job? Here’s an overview of the 7 best IP reputation checker tools and what they do.

Best ForStarting Price
Sender ScoreAt-a-glance overview of sender reputationFree
TalosSeeing the impact of shared servers on deliverabilityFree
MxToolboxIn-depth reputation analysis and blocklist checks$129/mo
Google PostmasterAll-round email performance analyticsFree
BarracudaCentralReal-time verified reputation rating Free
MailTesterSender reputation monitoring and list hygiene for email marketing$27/mo
SendForensicsIntegrating deliverability tools with your email marketing platform$39/mo

What is IP Reputation and Why Check It?

Everything connected to the internet uses Internet Protocol, or IP, to communicate. And everything that uses IP has an IP address. That’s every website, every mail server, every laptop or mobile device, every router or modem. Every IP address is a unique number. IP addresses are essential for identifying and finding assets online. Nothing can work online without one.

Every email you send carries the IP address of a particular email server. This address lets the receiver’s email client determine where the email is coming from. But it also does more than that. The receiving client can also see sending data from that server. If emails from that server have a high bounce rate or often get sent to the spam folder, email providers get suspicious. The data that makes them suspicious adds up to a poor IP reputation. It’s like waving a red flag to the spam filters.

None of this might be your fault. If you use any public email provider, you will be sharing an email server with other users. You might follow all the rules of spam-free email. But if others don’t, it will affect the server’s IP reputation. Your emails get penalised as coming from an untrustworthy source all the same. Most email service providers for small businesses also use shared IPs.

That’s why it’s worth checking IP reputation regularly. If you’re sending emails with a poor reputation, you want to know about it, fast. Otherwise, your campaigns are doomed to underperform before they even start.

7 Best IP Reputation Checkers for Email in 2024

IP reputation checkers mean you never have to send an email campaign blind. If there’s a risk of your messages being snared by spam filters an issue, you get an advance warning. That way, you can take steps to put it right and improve your deliverability.

Here’s the detail on how our top 7 IP reputation checkers work and what they tell you.

1. Sender Score

sender score domain and ip reputation service

Sender Score is incredibly easy to get started with. All you do is paste the IP address of your ESP into the home page. You’re then asked to confirm your email address and account details. Including your country and approximate sending volume. 

Sender Score gives you a score out of 100 for your IP reputation. Anything above 70 is classed as good. Anything below 70 and spam filters will be blocking a lot of your messages. 

sender score ip reputation scores

You get a breakdown of where that score has come from. The analysis is based on activity over the last 30 days. The ‘Reputation Measures’ cover things like spam complaints or your emails being blocklisted. Plus how many emails have been picked out by spam filters. And how many spam traps you’ve sent to.

Sender Score includes other tools that let you dig into the details. You can look up the reasons why your emails are bouncing. And check your lists for fake or unused accounts and spam traps. 

Sender Score is free to use.

Sender Score Pros

  • Free to use
  • Very simple and user-friendly
  • Gives you details on where you can improve your sender reputation
  • Additional tools like domain reputation and list quality checks

Sender Score Cons

  • Limited tools for improving your sender reputation

2. Talos

Talos ip & domain reputation center

Talos is a cybersecurity firm owned by software giant Cisco. It specializes in digital threat intelligence. One of its tools is an IP & domain reputation checker. The main purpose is to let you look up emails you receive to see if they are legitimate. But you can also use it to measure the sender reputation of your email IP address.

Talos ranks sender reputation as good, neutral and poor. It also provides a spam-level rating for the amount of spam coming from an IP address or domain. This is given as a low, medium and high rating. Other useful information includes any blacklists your IP address is included on.

Talos IP reputation check data

One of Talos’s best IP reputation features is a list of all the other IP addresses sharing your server. It provides a reputation rating for them all. If you see lots of poor ratings, you know what’s the cause.

Overall, Talos is geared more towards checking threats from other email addresses. If you see anything suspicious, you can issue a ticket. You need a Cisco account for this. But you’ll get support to protect your digital assets. And Cisco publishes details of spam and malware threats in real-time. Including an interactive map showing where they come from.

Talos’ IP reputation checker tool is free to use and you don’t need an account.

Talos Pros

  • Free browser tool
  • Simple ‘traffic light’ rating
  • Tells you if your IP address is on any blocklists
  • Shows sender reputation for other IP addresses using the same server

Talos Cons

  • Limited detail on what is causing a poor reputation. More of a tool for checking threats from emails you receive

3. MxToolbox

MxToolbox ip reputation check supertool

MxToolbox is an advanced reputation management platform. It offers diagnostic features for checking email health. And an advanced range of tools for improving deliverability on paid plans.

The software’s ‘SuperTool’ offers 37 different lookup features. This includes checking your IP address against 100 different blocklists. You can also test response times from an email server. Slow server performance can cause deliverability issues. A Domain Health check runs dozens of performance checks to see how everything is running.

One very handy tool is the MX Lookup feature. MX, or mail exchange records, route messages to mail servers. These records let you look up IP addresses from a domain name. Great if you don’t know your email server’s IP address.

Some of the tools let you monitor if your domain has been spoofed or hacked. Having your email domain, IP address or server used by fraudsters can be devastating for IP reputation. These tools include SPF and DKIM security checks.

MxToolbox delivery center

All of the above is free to use for a single domain. You also get weekly blacklist checks. Paid plans give you access to the Delivery Centre, starting at $129 a month for 5 domains. And you get inbox placement analysis, delivery performance reports, complaint reporting, active blacklist and domain impersonation protection.

MxToolbox Pros

  • Weekly checks against 100+ blocklists
  • 37 reputation check tools, free for a single domain
  • SPF and DKIM lookup to check your domain hasn’t been spoofed
  • IP address look up from domain name

MxToolbox Cons

  • Delivery Centre features are impressive but expensive

4. Google Postmaster Tools

Google Postmaster tools ip reputation service

Google Postmaster Tools is an email performance analytics service. It includes IP and domain reputation analysis. But it also covers things like spam rate, authentication, and delivery errors.

Postmaster Tools is for anyone sending high email volumes using Gmail. You need a Google account to use it. But it’s free to anyone who does. 

There’s a fairly lengthy registration process. You have to verify your domain to get started. This has to be your authentication domain, or SPF or DKIM. You then have to add users via their Google Account email address. You can register more than one domain.

Once registered, Postmaster Tools works as an analytics dashboard. It reports on IP and domain reputation in 4 tiers: high, medium, low and bad. If your reputation comes out as bad, you know you have a real problem with deliverability.

The spam rate and more detailed Spam Feedback Loop (SPL) data flag when spam becomes an issue. This may be a problem with a single campaign, suggesting you need to revisit your content. Or it may persist over time, suggesting you need to look at your contact list.

Delivery error data provides details about why your emails aren’t landing. This could be because of poor reputation, missing authentication or being blocklisted. Whatever it is, you know where you need to take action.

Google Postmaster Pros

  • Free if you have a Google Account
  • Live dashboard of email performance analytics
  • At-a-glance summary of IP and domain reputation
  • Delivery error reports telling you where. 

Google Postmaster Cons

  • Not the easiest to set up

5. BarracudaCentral

BarracudaCentral network security data service

BarracudaCentral is a cybersecurity specialist that tracks threat data across the internet. This includes monitoring spam emails and threats like phishing and distribution of viruses.

It runs the Baracuda Reputation System, a database of IP addresses linked to sending spam. This database powers BarracudaCentral’s own Spam and Virus Firewall products. But anyone can look up IP addresses for free.

BarracudaCentral ip reputation lookup

All IP addresses marked as ‘poor’ are manually verified. This makes sure that you can have a high level of trust in the results. But, you don’t get a breakdown of the details. An IP’s reputation is simply reported as ‘poor’ and that’s it. If your IP address gets flagged for a poor reputation, there’s a URL to a help page explaining why. But this lists generic reasons, not specific findings for your IP address.

BarracudaCentral’s other main product is a block list. This makes its IP and domain reputation data available as an additional spam filter for email clients. Again, it’s free to use. You can request the removal of your IP address if you have reason to feel it’s included incorrectly.

BarracudaCentral Pros

  • Free anti-spam tools
  • Threat analysis
  • Manually verified IP reputation check
  • High accuracy in identifying spam

BarracudaCentral Cons

  • Limited information for email senders if your IP reputation is listed as poor

6. MailTester

MailTester mail verification and deliverability suite

MailTester is made to increase deliverability rates for email marketing campaigns. Its core features are email list verification and deliverability analysis. Both of these include IP reputation tools as part of the platform.

Mail Verification flags whether any emails in your list are on blocklists. Sending to undeliverable emails doesn’t just result in a higher bounce rate. It harms your sender reputation. Mail Verification also checks for spam traps, disposable emails, invalid or inactive domains and MX records. Suspect emails are removed from your list automatically. You can verify whole lists in bulk. Or check them one at a time.

The Inbox Tester checks if your email will pass the spam filters of all major email clients. This includes checking if your IP is on any blacklists. But it also covers DKIM, SPF and DMARC authentication. It gives you a full report into whether your emails will be flagged as spam, and why. 

MailTester pricing starts at $27 a month for 5,000 email verifications, 10 inbox reports, and 5 blocklist checks. You can also buy credits to use on a pay-as-you-go basis. This starts at $19 for 5k credits. There’s a 14-day free trial with 100 free credits.

MailTester Pros

  • List verification and deliverability testing in one place
  • In-depth analysis of your sending activity, including IP reputation
  • Automatic removal

MailTester Cons

  • It’s on the expensive side

7. SendForensics

SendForensic reputation dashboard

SendForensics promises to help keep your emails out of spam folders. It offers AI-powered deliverability analysis for individual emails and in-depth sender reputation monitoring.

Information about your sender reputation is provided via a dedicated Reputation Dashboard. This allows you to track your reputation over time. It includes IP and domain reputation analysis. But also details of any blocklists your IP appears on. Plus bounce, complaint and unsubscribe rates.

SendForensics provides DMARC records to counter email spoofing. You get alerts in real time as and when issues are identified.

And it uses Machine Learning to analyse email content for ‘spammy’ language. Or anything else that might look suspicious to spam filters. This gives you the chance to make changes before you hit send.

SendForensics integrations

There are 29 direct integrations, including email marketing platforms like Brevo, ActiveCampaign, AWeber, GetResponse, Benchmark, and Mailchimp. With SendForensics plugged in, you can improve IP reputation. And track whether transactional emails are being flagged as spam.

Pricing starts at $39 per month for 2 domains and 2 users. There are no limits on spam tests. There is a 14-day free trial.

SendForensics Pros

  • In-depth reputation analysis
  • Dashboard to track sender reputation over time
  • AI deliverability tools
  • Integrations with major email marketing platforms

SendForensics Cons

  • Would be even better if it instantly gave you a single reputation summary score

Is it enough to have IP reputation checkers?

Many of the services we’ve picked out offer IP reputation checks alongside other tools, like email verification tools. There’s a good reason for that. 

An IP reputation check can tell you clearly that your emails are at risk of being flagged as spam. But getting high deliverability rates depends on understanding why your emails are ‘spammy’.

If you want to maximize deliverability, you have to pay attention to all of the following:

  • IP and domain reputation
  • List hygiene
  • IP warm-up
  • Offering clear unsubscribe options
  • Using separate servers for marketing and transactional emails
  • Email authentication protocols

IP Reputation vs. Domain Reputation

Many reputation tools check both IP address and domain reputation. What’s the difference?

Web and email domains are the words people use to identify a site, page or account. So emailvendorselection.com, for example. IP addresses are the numerical codes computers use to identify a site, page or email account/server. Or any other type of asset that connects to the internet.

Unless you pay for a dedicated private server, your email servers will be shared by other users. All emails sent from a single server will have the same IP address. Spammy activity from one user will harm everyone’s IP reputation. It’s up to the provider to control and manage the servers.

ESPs typically send from more than one mail server. So emails from your domain are being sent from more than one server. A domain reputation check looks at activity across all servers, rather than for a particular IP address. 

Your email also has more than one type of domain. There’s the ‘from’ address that we all call our email address. But there’s also a return-path domain, which dictates where bounced emails are sent. And the DomainKeys Identification Mail (DKIM), which is a type of authentication domain. More on that under Email Protocols.

Email List Health

Good deliverability also depends on practising good list hygiene, including email scrubbing. Most businesses use sign-up forms to build contact lists for email marketing. If subscribers or customers mistype their email address, sending to it will result in a bounce. And bounces harm sender reputation.

Equally, over time people will stop using email addresses. Or their inbox becomes full. Sending to these also causes bounces. Worse, you could end up with spoofed or fake email addresses. Or worst of all, a spam trap email address. A fake address deliberately planted to prove you don’t check your lists enough. Sending to these harms your sender reputation.

The best way to keep your list clean? Use email list cleaning services, like Bouncer. An email verification or list cleaning tool removes inactive and invalid emails from an email list. They check MX records, SMTP protocols, if an email has the right syntax or if it’s on a blacklist. This may sound pretty techy but it’s super easy with email verification software. You’ll get easy-to-understand results, like this:

email verification results

Email Protocols

Some email protocols make sure servers and exchanges can communicate with each other. Examples include SMTP, IMAP and POP standards. An SMTP server is the application and hardware that sends your email messages. Find a list of the best free SMTP servers here to send your email campaigns.

Other protocols are used for authentication. Authentication protocols confirm that an address is authorised to use a particular domain. Spam filters will block and flag any emails that don’t have the correct records. This is great for combating hacked email accounts and spoofing. But it also affects deliverability if you don’t follow the protocols correctly.

The 3 most common authentication protocols are:

  • SPF: Allows domain owners to specify which servers and IP addresses can send emails on their behalf.
  • DKIM: Uses digital encryption keys to match emails to DNS (domain name) servers.
  • DMARC: Combines SPF and DKIM and lets domain owners state how emails that fail authentication are handled.

Concluding IP Reputation Checker Tools

So that’s our view on the best IP reputation checkers out there right now. If you want to increase your email deliverability, you have to take your sender reputation seriously. IP reputation services give you the insight you need. They let you see where you could be caught out by spam filters. So you can take action before you hit send.

But what’s the right IP reputation checker for you? Part of it depends on the size of your business. And how much information do you need. If you’re a small business, you probably prioritise value and ease of use. Free tools like Sender Score are enough to tell you you have a reputation issue. With enough detail for you to act on.

If you’re a big business sending emails at scale, you will want more. For a start, you might have multiple email domains to check. Sending more emails means more risk of being caught on blocklists. MxTester’s checks against 100+ blocklists are the best out there. And while on the pricey side, its deliverability tools will guarantee better performance.

FAQs about IP Reputation Checkers

What is an IP reputation checker?

An IP reputation checker is an online tool that assesses the sender reputation of an email server’s IP address or domain. Email servers get judged by spam filters on how much spam they send. As well as other risks. The higher the spam risk, the worse the sender reputation. Spam filters will block a lot of emails that come from high-risk servers. So a poor sender reputation seriously harms deliverability rates. 

IP reputation checkers rate your sender reputation before you get caught out by spam filters. This gives you the chance to protect or improve IP reputation. 

What is IP reputation score?

An IP reputation score is a spam rating for your IP address. Some IP reputation checkers, like Sender Score, give the rating as a numerical score. Sender Score rates your IP reputation from 1 to 100. Anything above 70 is ‘good’. Anything below, you should take steps to improve it.

How do I know if my IP is blacklisted?

To find out if your email IP address is blacklisted, you can use an online IP reputation checker. Blacklists and blocklists are databases of email servers that have been flagged for sending spam or malicious email. If your mail server IP is on one, most of your emails will get blocked by spam filters.

IP reputation checkers mainly rate your IP for spam. But many also let you run specific checks against blacklists. If you see your IP on a blacklist, you may be able to appeal to get it removed. There are lots of different blacklist databases. So you should look to see how many a reputation tools check against, MxToolbox checks against 100+ for free.

What is an IP address reputation database?

An IP address reputation database is a listing of email server IP addresses. It contains data about the sender reputation of each address. Most of this data relates to spam activity or the sending of malicious emails.

Some IP reputation checkers keep an IP reputation list to speed up checks. This means they don’t have to run brand-new tests every time. Some databases only store data on IP addresses with a negative reputation. These can be used as blocklists helping spam filters identify which emails to block.

About Paul Newham


Paul Newham is a content writer specialising in business blogging, report writing, software reviews, and online copywriting. He has 5+ years of email marketing, marketing automation and software review experience. He tested over 60 business software including email marketing tools, CRMs, outreach services, SMTP providers, email verification, and AI writing tools.

With a background in journalism and PR, he understands business content from both sides. And knows what makes for great, engaging copy, but also understands that for businesses, the written word is all about driving value.

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