Reading an IP reputation

1 Introduction

IP reputation is like a credit score for an IP address. Just as a bank checks your credit score before lending you money, security systems check an IP's reputation before allowing it to communicate with your network. An IP that has been involved in spam, attacks, or malware distribution gets a bad reputation -- and that reputation follows it across the internet.

100+

Reputation databases available

Real-time

Reputation updates continuously

0-100

Typical reputation scoring range

2 How It Works

Use the IP checker below to look up the reputation of any IP address. You will see geolocation data, the owning organization, and whether the IP appears on any blacklists or has been associated with malicious activity.

How reputation is calculated

1

Data collection

Honeypots, spam traps, firewalls, and security vendors worldwide report observed malicious activity from IPs

2

Scoring

Reports are aggregated and weighted. Recent activity matters more. Multiple independent reports increase confidence.

3

Classification

The IP is classified as clean, suspicious, or malicious, often with a category (spam, scanner, botnet, C2)

3 Detailed Analysis

Major reputation databases

AbuseIPDB

A community-driven database where users report abusive IPs. Provides a confidence score from 0% to 100% based on the number and recency of reports.

VirusTotal

Aggregates results from 70+ security vendors. Shows which vendors flag an IP as malicious and what types of threats have been associated with it.

Shodan / Censys

Internet-wide scanners that catalog what services are running on an IP. Useful to see if an IP runs suspicious services like open proxies or Tor relays.

Spamhaus / DNSBL

DNS-based blocklists focused on spam and botnet activity. Email servers commonly check these lists to filter incoming connections.

Understanding reputation scores

0-25

Clean

No or very few reports. The IP is likely legitimate and safe.

25-75

Suspicious

Some reports exist. Warrants further investigation before blocking or trusting.

75-100

Malicious

Widely reported as abusive. Should be blocked and investigated if found in your logs.

Reputation is not permanent

An IP's reputation changes over time. A compromised server can be cleaned up and regain a good reputation. Conversely, a clean IP can become malicious if the machine is compromised. Cloud provider IPs are particularly volatile -- they are frequently reassigned between customers, so yesterday's legitimate server might be today's attack platform.

4 Red Flags

IP flagged on multiple blacklists

An IP appearing on one blacklist could be a mistake. An IP on five or more independent blacklists is almost certainly involved in malicious activity.

Recent abuse reports

If an IP has received abuse reports in the last 24-48 hours, it is actively being used for attacks. Older reports are less concerning as the situation may have been resolved.

IP tagged as C2 (Command and Control)

If an IP is classified as a C2 server and a machine on your network is connecting to it, that machine is very likely infected with malware receiving instructions.

IP belongs to a bulletproof hosting provider

Some hosting providers knowingly shelter criminal activity and ignore abuse reports. IPs from these providers are inherently high risk.

Clean reputation but suspicious context

A clean IP does not guarantee safety. New attack infrastructure has no reputation yet. Always combine reputation data with other context like geolocation, ASN, and observed behavior.

Reading an IP reputation

1 Introduction

2 How It Works

How reputation is calculated

3 Detailed Analysis

Major reputation databases

Understanding reputation scores

Reputation is not permanent

Try it on mlab.sh

4 Red Flags

Related Modules

What is an IP address?

Understanding ASN and geolocation

What is an IOC?