IP Reputation: Why It Matters and How To Improve It

IP reputation measures the trustworthiness or credibility of an IP address based on its historical behavior and activities. This trustworthiness is often quantified as an IP score, with higher scores indicating a positive reputation and lower scores signaling potential risk. If an IP address sends authentic, spam-free emails, it gets a positive IP reputation score. On the other hand, if associated with bulk spam, malware distribution, connecting to dangerous domains, or originating from suspicious locations, an IP address will have a poor IP reputation.

Consider an attacker sending phishing emails as an example. Recipients flag these emails as malicious to their mailbox providers. The attacker’s IP address is subsequently associated with malicious online behavior, hurting their IP reputation and lowering their IP score. This leads to the attacker's emails being marked as spam or even blocked from delivery.

But IP reputation also affects legitimate business owners. Mass marketing email campaigns seem like a great way to communicate, but they can lead to a low IP reputation if not executed properly. IP reputation will track email characteristics like:

• Spam complaints

• High email volume

• Unknown recipients

• High bounce rate

• Email frequency

• Domain reputation

• IP history (if malicious behavior has been detected from the same server, for example)

Analyzing these characteristics and other factors helps IP reputation trackers gauge the level of risk associated with a specific IP address.

The end goal of any email marketing campaign is to have recipients open and engage with their emails. But this can never happen if the emails aren't delivered in the first place. A negative IP reputation can lead to email providers marking your legitimate emails as spam.

Organizations must build a positive IP reputation to ensure email delivery. Part of this formula requires fewer spam complaints and a low bounce rate from viewers. One strategy to ensure a positive IP reputation is to only send emails to people who have signed up for your messages. In the EU, organizations may violate GDPR laws if a marketing email is sent to someone who never signed up for it.

Besides ensuring emails come from authentic IP addresses, IP reputation is also important in the fight against cyberattacks. By ensuring the legitimacy and quality of an IP address, IP reputation helps spot malicious intentions, send suspicious emails to the spam folder, or block them entirely.

While IP reputation focuses on the trustworthiness of an IP address, domain reputation assesses the credibility of a domain name used in email communications. Both play crucial roles in determining email deliverability and ensuring that your messages reach your intended audience.

Here are more specific differences between the two:

Both IP reputation and domain reputation play a crucial role in email deliverability. Email service providers and spam filters evaluate both when determining whether to deliver, reject, or route an email to the spam folder.

A weak score in either area can hurt your chances of reaching the inbox. For instance, even with a solid IP reputation, emails may still be flagged if the sending domain has a history linked to spam or phishing.

Building a Strong Reputation

To maximize email deliverability, organizations should focus on building and maintaining both a positive IP reputation and a strong domain reputation. This includes:

• Consistent Sending Practices: Avoid sudden spikes in email volume and maintain regular sending patterns.

• Engagement with Recipients: Send emails to engaged users who are likely to open and interact with your messages.

• Proper Authentication: Implement SPF, DKIM, and DMARC to authenticate your domain and prevent email spoofing.

• Monitoring Both Reputations: Regularly check both your IP and domain reputation using reputable tools to identify and address any issues promptly.

By understanding and managing both IP and domain reputation, you can enhance your email deliverability and protect your organization's communication channels.

An IP reputation attack occurs when an attacker hijacks a website or server and negatively impacts its IP reputation. This can happen in a variety of cyberattacks. Some ways an attacker can affect a company's IP reputation include:

• Hacking the company website

• Hijacking servers to send malicious emails

• Using a system for Distributed Denial-of-Service (DDoS) attacks

IP reputation can dictate the success or failure of an email marketing campaign. If you're unsure where your organization's IP reputation stands, now is the time to verify you are in good standing.

First, gather the IP addresses associated with your organization. Check your Sender Policy Framework (SPF) record to find IP addresses of email servers authorized to send emails on behalf of your domain. This should include IP addresses from:

• Your email provider (like Gmail or Outlook)

• Any subdomains

• Third-party mail servers like Mailchimp

Next, choose an IP reputation tool. Use a tool with real-time data since static lists are quickly outdated. Some of the available options include:

• Sender Score: Sender Score is calculated on a rolling 30-day average, ensuring you receive timely data on how ISPs and customers view your emails.

• BrightCloud: BrightCloud provides a summary of IP address data, including information on threat status and threat analysis.

• Google Postmaster Tools: For organizations using Google Workspace, Postmaster provides data on delivery errors, spam reports, and performance issues.

• Microsoft SNDS: For organizations using Outlook, SNDS sends reports containing detailed data about individual IPs and when users mark your messages as junk.

While some tools only provide reports, Sender Score offers an actual score to rank an IP reputation from 0-100, which falls into three categories: Needs repair (0-70), Room for improvement (70-80), and Great reputation (80-100).

A negative IP reputation means your organization has work to do to verify its legitimacy to ISPs and email filters. This may take some time to rectify, but it's important to establish your reputation as a trusted source.

Here are some email-related steps you can take to start improving your IP reputation:

1. Reassess your email strategy: If recipients mark your emails as spam, they may have a reason. Focus on quality over quantity so your emails aren’t regularly seen as spammy.

2. Start slow: If you have a new SMTP server, domain, or IP address, you need to warm up the IP to build a reputation. High email volume from a new sender may raise red flags from ISPs and spam filters.

3. Stay consistent: After ramping up sending, maintain consistent email volumes. Large spikes in sending volume may look suspicious.

4. Use separate email servers: Marketing email needs are different from other day-to-day business emails. By using different email servers for each business need, you can protect and improve your IP reputation.

5. Respect the unsubscribe: If you don’t give users an option to unsubscribe, they’re more likely to mark your emails as spam. And if they want to unsubscribe, they’re not your ideal target audience in the first place.

6. Trim your email list: Don’t send emails to inactive or disengaged users. Work on smaller, more personalized mailing lists with active recipients. Engagement is more important than the size of a mailing list.

Improving IP reputation goes beyond the content of your email:

• Adhere to standard email protocols like SPF, DKIM, and DMARC to authenticate your emails and prevent spoofing.

• Monitor servers, systems, and devices for any potential command-and-control (C2) connections or malware infections that could compromise your IP reputation.

• Regularly check your IP and domain reputation scores using reputable tools to identify issues early and take corrective actions.

By proactively managing your IP reputation, you can enhance email deliverability, protect your brand, and ensure effective communication with your audience.

To learn more about how Abnormal Security can improve your email security, request a demo today.