Question 1

What is IP reputation?

Accepted Answer

IP reputation is a score or classification that describes how trustworthy or risky an IP address is, based on historical behaviour. IPs used for spam, malware distribution, brute force attacks, or other malicious activity earn poor reputation scores in threat intelligence databases.

Question 2

Why is my IP address blacklisted?

Accepted Answer

Common reasons include: sending spam or phishing emails, hosting malware, being part of a botnet, conducting port scans or brute force attacks, or being assigned by an ISP to a shared pool that was previously abused. Shared hosting, VPNs, and Tor exit nodes are frequently blacklisted.

Question 3

How do I delist my IP from a blacklist?

Accepted Answer

Each blacklist has its own delisting process. For major blacklists: Spamhaus (check.spamhaus.org/delisting), MXToolbox (mxtoolbox.com), and Barracuda (barracudacentral.org). Fix the root cause first (malware, compromised account) before requesting removal.

Question 4

What is AbuseIPDB?

Accepted Answer

AbuseIPDB is a collaborative blacklist database where network administrators and security professionals report IPs involved in malicious activity. It tracks attacks, spam, port scans, and other abuse. An IP with a high confidence score indicates widespread abuse reports.

Question 5

How do I get delisted from Spamhaus?

Accepted Answer

Start at check.spamhaus.org, look up your IP, and follow the removal link for the specific list you are on — SBL, XBL, and PBL each have a different process. Fix the underlying issue first (patch the compromised host, close the open relay, stop the spam source), because Spamhaus re-lists quickly if abuse continues. PBL entries cover dynamic or residential ranges by policy and are often resolved by your ISP rather than by you. Delisting is free — never pay a third party that promises expedited removal.

Question 6

Why does a brand-new VPS IP already have a bad reputation?

Accepted Answer

Cloud and VPS providers recycle IP addresses, so a fresh IP was almost certainly used by previous customers — and if one of them sent spam or ran malware, the blocklist entries and poor sender history stay attached to the address. Before building mail infrastructure on a new VPS, check the IP against the major DNSBLs and request a different address from your provider if it is dirty. This is one reason many teams route outbound mail through a dedicated email service instead of sending directly from raw cloud IPs.

Question 7

Should I send email from a dedicated or shared IP?

Accepted Answer

A shared IP pools your traffic with other senders: you benefit from established volume but inherit the worst behaviour of your neighbours. A dedicated IP gives you full control of your reputation, but it must be warmed up gradually — mailbox providers throttle or junk sudden volume from an address with no sending history. As a rule of thumb, consistent senders with meaningful volume benefit from a dedicated IP, while low-volume senders are usually better off on a well-managed shared pool.

Question 8

How often does IP reputation change?

Accepted Answer

Reputation is dynamic. DNSBLs add and expire entries continuously — often within hours of observed abuse — and mailbox providers recalculate sender scores over rolling windows of days to weeks. A clean check today does not guarantee a clean check next week, which is why teams that depend on email deliverability monitor their sending IPs on a recurring schedule rather than checking once.

IP Reputation Checker

Why IP Reputation Decides Whether Your Email Arrives

What the Results Mean

Frequently Asked Questions