totally recommend Invaluement... they block things that get through other filters... Great job - keep it up

Mitchell P.  June, 2018 source (A LinkedIn login may be required to view this review.)

The only RBLs I trust as strict accept & reject decision making are Spamhaus and Invaluement.

popowich, administrator  March 21, 2015 source

“You also may want to look at the Invaluement IP/URI lists. ...Detection rate is very good ...FP level is extraordinary.” [which means: mistakes are rare]

Axb  March 27, 2015 source

“ivmURI and ivmSIP are good solid and professionally operated lists... high effectiveness... extremely low false positives

The CBL dnsbl  source

block more spam

THE PROBLEM: So you’re blocking almost all spam (ALMOST!), but your users are STILL frustrated with the spams that slip past your spam filter, which can STILL sometimes add up to a sizable number of spams making it to the inbox, in spite of your overall high percentage of blocked spam. Often, certain series of elusive spams will target certain users, and they really don’t care that these egregious spams they keep seeing in their inbox are a tiny percentage of all blocked spam. They want results, not excuses!

FROM BAD TO WORSE: While some of those spams merely annoy your users and waste everyone’s valuable time, even much worse, OTHER such spams can trick users into clicking links that install malicious malware (sometimes ransomware!) or lure them into a phishing scam (possibly compromising your organization’s bank account information!). Often, you’re the one who has to fix that mess, and you may even get blamed for it! Large extra expenses and tedious hours of work are often part of the damages caused by just one such data breach or infection!

As a result, these remaining unblocked spams are causing BIG problems and relentless complaints! And there isn’t an easy fix because...


  1. They are often the hardest to block, so they get past many spam filters and DNSBLs!
  2. Most of the (overly-aggressive!) methods that do block them ALSO block far too many legitimate emails!
  3. Other solutions that might block these very elusive spams typically require a time-consuming and extremely expensive complete overhaul of your spam filtering system.

THE SOLUTION: Invaluement is the PERFECT solution because (1) our service easily integrates into your existing spam filter and (2) blocks a large portion of these remaining and most elusive spams that even the best spam filters miss. Unlike most other solutions, (3) invaluement does this while keeping false positives at industry-leading extremely low levels.

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  1. No other DNSBL blocks as much spam that Spamhaus misses as does Invaluement, unless that other DNSBL blocks significantly more legitimate messages than invaluement!
  2. In contrast to an entire massive spam filter renovation, setting up invaluement is fast, easy, and inexpensive.
  3. Invaluement easily integrates into almost all spam filters.
    (For example, our direct query option can be configured in seconds and does not require any hardware or software installation.)

HOW DOES THIS WORK? Really, you don’t even need to know all the technical details because typically, to implement this, you just copy a particular host name (that we will assign to you), paste that into a form field in your spam filter, hit “save”, and start enjoying better spam filtering. This only takes a few minutes. For most, it is that fast and easy! But if you want more technical details, view our how DNSBLs work page. Or, if you are ready to experience less spam, with only a minimal effort and cost, and without any noticable increase in false positives, get a FREE 7‑DAY EVALUATION today!

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THE DETAILS: Up to this point on this page, you have read a general overall summary of what invaluement can accomplish for you. And you were invited to learn more about the technical details about how DNSBLs work. Below are more specific details about each of the three individual DNS anti-spam lists offered by invaluement: ivmSIP, ivmSIP/24, and ivmURI. If you are extremely geeky (like we are!), you’re gonna love this! But you do NOT need to understand all of these technical details to implement invaluement and start improving your spam filtering system today!

invaluementURI is an anti-spam URI dnsbl, similar to and Therefore, unlike an “RBL”, and sometimes called a domain dnsbl, it actually lists both domain names and a few IPs, which are all found within the clickable links in the body of spams. These domains are generally not seen in legitimate e-mails, except for rare instances when a normally-innocent domain has been hijacked by criminal spammers. However, most ivmURI-listed domains are actually owned by spammers. ivmURI lists many such domains before other domain/URI anti-spam lists, yet with an industry leading low-FP rate. Also, much spam is sent from the MTAs of very large ISPs/hosters and, therefore, cannot be blocked with a senders-IP list without causing massive FPs. But many of those spams can be safely blocked with ivmURI. Start your Free Trial today.

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“When I ran shared hosting, it was amazing the number of times I’d see a site on the Invaluement blocklist and think ‘hangon, there’s nothing wrong with that domain, we host it!’ then check the site and find it hacked.”

Dom T.  June, 2018 source (A LinkedIn login may be required to view this review.)

“I want to say, the Invaluement RBL is awesome. It is very cheap and almost as good as spamhaus based on my reports so I recommend everyone purchase it... I am not affiliated with the IVM product, just a happy customer.”

Dave J.  September 30, 2014 source

free trials are available


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invaluementSIP is an anti-spam list consisting of IP addresses which either only send spam or which emit an extremely high percentage of spam. Most ivmSIP-listed IPs are from botnets, very elusive snowshoe spammers, or irresponsible ESPs. Rarer listings include short-term listings of low-volume and normally legit senders who currently have a compromised system that is facilitating the sending of massive amounts of spam. ivmSIP is not trying to be a list-every-botnet dnsbl. Therefore, it cannot replace Spamhaus. Instead, it focuses on spammy IPs either overlooked or not yet listed by Spamhaus, and has an industry-leading low FP rate which is comparable to that of Spamhaus’ Zen list. Start your Free Trial today.

“The Invalument RBL service... is extremely good and very fast at responding and updating their list on the fly.”

Mark G.  December, 2015 source

“...been using them for 3-4 years. A lot of blocking that doesn’t overlap with Spamhaus, very few false positives... Well worth it.”

Dave P.  July 29, 2014 source

“Invaluement... the only ones we have found that are stopping the snowshoe effectively with little if any false positives

Steve  November 22, 2014 source

get access today by clicking


invaluementSIP/24 is an anti-spam list which preemptively lists spammers’ ip ranges or subnets where patterns of spam-sending from those blocks have been detected. Unlike other /24 lists, ivmSIP/24 does a great job of NOT listing those nearby IP ranges which are owned by innocent bystanders. This results in far fewer FPs than other /24 lists. ivmSIP/24 made history by being possibly the first anti-spam list to primarily target snowshoe spammers, even before Spamhaus came out with their CSS list. Actually, ivmSIP was already targeting snowshoe spam before ivmSIP/24. Later, ivmSIP/24 was created to provide an even greater emphasis on listing this very elusive type of spam. Start your Free Trial today.

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“The invaluement RBL is not expensive and it is awesome... it’s almost as good as Spamhaus Zen.”

D. Jones  March 27, 2015 source

“We’re running on several servers now, and have been downright amazed.”

SFPete  January 21, 2014 source

get rsync or direct query access


invaluement globe logo

They make a great “team”. When combined, they are an industry leader in listing spams that are not listed by Spamhaus’ Zen list, yet with an extremely low FP-rate comparable to that of Zen. Don’t be surprised if, in YOUR free evaluation, you find that all other sender’s IP DNSBLs in the industry either don’t list as many of the spams missed by Zen and/or have distinctly more FPs. Previously, only ivmSIP could even approach such a claim. Then, over time, ivmSIP/24 got better and better at having fewer and fewer FPs (which was NOT an easy task for a subnet-oriented list!). Now, working together, they are amazing. Skeptical? See for yourself! Start your free trial today!