IP Address Reputation Basics

When the time comes to sell, buy, or lease an IPv4 address, multiple factors will come into play. One important element is IP address reputation. Neglect this factor and a business can wind up with a block of addresses that hamstrings their online efforts before they even begin.

Just as a car’s vehicle history influences its value, an IP address’ reputation can significantly impact its utility and worth in the digital marketplace. A tarnished reputation can hinder email deliverability and even prevent businesses from operating online.

But what does IP address reputation mean? What factors impact reputation? And how does one check to ensure a coveted IP address block is reputable?

What is IP Address Reputation?

At its essence, IP address reputation boils down to one question: how trustworthy is this IP address source?

Address reputation scoring is a measurement of the address’s historical behavior and associated activities. It functions similarly to a credit score—a measurement of trustworthiness for an IP address. 

While this reputation might be invisible to the casual user, the automated systems on the back end of websites will see it. Networked systems import reputation lists and use them in combination with the operator’s policy to decide how to treat communication from IP addresses. For instance, email will be rejected when reputation list managers see a lot of spam sent from an IP address. IBM uses several classifications for types of behavior that will lead to a negative reputation:

  • Anonymous proxies
  • Botnet Command and Control Server
  • Dynamic IPs
  • Malware
  • Scanning IPs
  • Spam

Much like a bouncer at a bar checking IDs at the entrance, IP address reputation is used to decide whether to accept email or let consumers buy products. Access is denied when an address is on an RBL (Realtime Block List). But addresses with a clean reputation are welcome. Many organizations configure the IP addresses of their business partners and other important networks to an allow list to avoid service interruptions.

Impacts of Address Reputation

When it comes to IP reputation management, three primary factors are impacted by address reputation:

  • Email deliverability – The stronger the reputation, the higher the likelihood that emails will reach an intended recipient’s inbox. Conversely, a poor reputation often results in the connection being closed before the message has even been sent.
  • Online credibility – Much like in the real world, a good reputation online can open doors which will influence search engine rankings for SEO, enable smoother interactions with web services, and contribute to a positive user experience.

Organizations use IP address reputation in combination with their own policy when deciding whether to accept or reject mail and other data traffic.

Factors that Influence IP Address Reputation

Several elements are factored into the reputation equation, including:

  • Address history – Prior usage of an IP address will have a major impact on its reputation. If it was previously associated with spamming, phishing, or other malicious activities, the new user of the address will need to correct the reputation. Ensuring that the RIR public records are updated is an important part of this. Most RBLs will automatically remove IP addresses shortly after they stop acting maliciously. All reputable RBLs provide a way to request a manual review and will not charge a fee for doing so.
  • Blocklisting – IP addresses can end up on RBLs if they have been previously identified as a source of spam, malware, or other harmful content.
  • Spam complaints – The total number of spam complaints received against an IP address will impact its reputation—the more complaints, the worse the reputational score.
  • Malware distribution or phishing attacks – If an IP address has been involved in distributing malware, hosting malicious content, or performing phishing attacks, it will have a diminished reputation.

Remote Block Lists: Gathering IP Address Reputation Information

Similar to how credit reporting companies track financial history, RBLs are the watchdogs of the digital world, automatically monitoring and cataloging activities of an IP address.

These databases maintain an active list of addresses that have been associated with unscrupulous behavior. If an address is granted this ignominious honor, it signals to all other sites and bots that the address may not be a trustworthy source.

Prominent RBL providers, such as Spamhaus, SpamCop, and SURBL, use different methodologies to evaluate IP address reputation. Some focus on the volume of spam, others on the nature of the spam, and yet others might look at additional factors such as user reports.

If an IP address block lands on an RBL, that status isn’t permanent. Addresses may cycle from malicious to benign and back several times over.

As WebRoot notes: “When looking at the top 50k IP addresses that recurred on our “malicious” list in 2020, 97.3% were caught displaying at least four distinct risk factors, such as spam sources. Almost half (45%) of the top 50K recurred during at least 2 different months, while 25.8% were seen doing something malicious every single month.” 

Limitations of IP Address Reputation

It’s worth noting that IP address reputation isn’t a perfect system. It’s not infallible and can be prone to false positives and false negatives. Innocent IPs may be flagged as malicious, whereas bad spammers go undetected.

An IP address’ reputation should be a guiding touchpoint rather than a final judgment on its trustworthiness.

Additionally, IP reputation isn’t static. It can be improved over time.

How to Improve IP Address Reputation 

There are actionable steps an IP address owner can take to improve its reputation, including:

  • Separate transactional and marketing emails – By segregating email domains, a business ensures that an issue with one doesn’t affect the deliverability of the other, especially since marketing emails are more likely to be perceived as unwanted or spam.
  • Follow email sending best practices – To prevent emails from being marked as spam, organizations should follow some basic best practices, such as:
    • Maintaining a healthy subscriber list
    • Ensuring that emails are relevant and provide valueAvoid sending unsolicited emails
    • Personalizing email content
    • Providing an easy opt-out for recipients
  • Regularly monitor IP address reputation – Maintain reputational standing by frequently checking RBLs and other IP reputation tools. Services like Cisco’s Talos will let you monitor the reputation of both your IP addresses and domain names.
  • Practice proactive reputation management – If an issue is flagged, don’t let the problem fester. Instead, nip them in the bud by responding with alacrity to any report.

IPv4.Global—A Trusted IPv4 Broker

An IP addresses reputation functions similarly to a credit score. A good one will enhance online credibility, improve email deliverability, secure a network, and even boost SEO rankings, but a bad one can result in emails bouncing to the spam folder, compromise network security, risk being blacklisted, and hamper overall digital presence.

But remember, an IP address’s reputation isn’t set in stone. If an IP address has a less-than-savory reputation—just as with a credit score—it can be gradually improved with time.

So, whether you’re looking to buy an IPv4 address block with an assuredly clean reputation, or looking to repair a block’s reputation before a sale, IPv4.Gobal is the trusted market leader. Our experts will guide you through the transfer process, which is a foundational step in improving a negative IP address reputation. We can also connect you with specialists who can help you contact blocklist operators if you need extra help.    

To discover more, reach out to our team today.