Blacklisted IP Address: Why It Happens and How to Get Removed

It means that at least one list your traffic is checked against has a negative entry for your address, so services that use that list treat you with suspicion. "Blacklist", "blocklist" and "denylist" mean the same thing; Spamhaus and many other list operators now say "blocklist". There are four kinds, and they have very different effects:

The last kind is a plain IP block, covered in why is my IP address blocked. This guide is about the first three: the shared lists and scores that follow an address from site to site.

An address is listed because traffic from it, or from its range, matched a list's rules. The common causes, from most to least under your control:

Carrier-grade NAT puts many customers behind one public IP, from a range set aside for it in RFC 6598 (100.64.0.0/10 on the inside), which is why a phone on mobile data can inherit a listing it did nothing to earn.

Most email blocklists work over DNS. A mail server that receives a connection from 192.0.2.99 reverses the address and asks the list's DNS zone for 99.2.0.192.list.example. If there is an answer, the address is listed; the answer "conventionally" is 127.0.0.2, and a TXT record often gives the reason (RFC 5782, 2010). Spamhaus ZEN combines its SBL, CSS, XBL and PBL lists into one zone you query once (Spamhaus: ZEN).

You can run the same lookup yourself:

# Is 192.0.2.99 on Spamhaus ZEN? Reverse the octets and query the zone.
dig +short 99.2.0.192.zen.spamhaus.org        # no output = not listed
dig +short 99.2.0.192.zen.spamhaus.org TXT    # the reason, if listed

# Every IPv4 DNSBL must list 127.0.0.2 as a test entry (RFC 5782, section 5)
dig +short 2.0.0.127.zen.spamhaus.org

What the answer means on ZEN (Spamhaus: zones and return codes):

The PBL zone is rebuilt and reloaded every 15 minutes, so a granted removal reaches lookups quickly (Spamhaus: PBL).

One catch: Spamhaus refuses queries that come through public DNS resolvers. When we ran the test lookup above on October 23, 2026 from a server that uses a public resolver, the answer was 127.255.255.254 with the TXT text "Error: open resolver", not the test listing. A 127.255.255.x answer is an error code, not a listing; check through your own resolver or a web checker instead.

Reputation scores work differently. A service collects signals about an address, such as abuse reports, spam traps, whether it belongs to a hosting, VPN or proxy network, and how much traffic it sends, and turns them into a number. AbuseIPDB, for example, gives each IP a "Confidence of Abuse" from 0 to 100, "based on user reports" (AbuseIPDB FAQ). Anti-bot services keep their own scores and rarely publish them; Cloudflare's bot score, for instance, runs from 1 (automated) to 99 (human) and combines the IP with many other signals (Cloudflare: Bot scores).

1. Find your public IP. Search "what is my IP" or open an IP lookup page. On mobile data or behind a VPN, it is the carrier's or the VPN's address, not your device's.
2. Check the email blocklists. MXToolbox's blacklist check tests an address "against over 100 DNS based email blacklists". For Spamhaus, use its own reputation checker at check.spamhaus.org: it names the list, gives the reason and is where removal requests start.
3. Check the abuse databases. Look the IP up on AbuseIPDB to see reports and its confidence score.
4. Read what each listing means. A Spamhaus PBL entry says the range should not send mail directly; it is a policy listing, not proof of abuse. An XBL entry says a device on that address looked compromised.
5. For proxy IPs, first get each proxy's exit IP and country from our proxy checker (it tests whether proxies work; it does not check blocklists), then run those exit IPs through the lists above.

If the lists show nothing but sites still challenge you, the cause is usually a site's own score or something other than the IP: see what proxies can and cannot fix.

Delisting works only after the cause is gone; lists that see the same traffic again relist the address, often for longer.

1. Read the exact rejection or lookup. A bounce that says the message was blocked using zen.spamhaus.org names the list, and the answer code (table above) tells you which part of it. Act on that list, not on a checker's total.
2. Fix the cause. Clean infected devices, update the router's firmware and change its admin password, close open relays, stop the script that scanned or brute-forced, change mail passwords and check the forwarding rules of hacked mailboxes.
3. Request removal from the list itself. For Spamhaus, run the IP through check.spamhaus.org and follow its ticket. Spamhaus takes removal requests only from the registered owner of the IP and not by email, and a request "does not guarantee that the removal will be granted" (Spamhaus FAQ). A delisting is not something a third party can sell you: it goes through the list's own system.
4. Wait out automatic listings. Many lists expire entries on their own once the traffic that caused them stops.
5. If the address is shared or recycled, ask your internet provider for another one. On a dynamic line, restarting the router may give you a new address.

Policy listings (Spamhaus PBL): when removal is possible

A PBL entry says the range "should not be attempting to directly deliver unauthenticated SMTP email" (Spamhaus: PBL). It is not an accusation, and most people on it need no removal:

Two rules trip people up: the removal system rejects requests sent from free email accounts (use an address on the mail server's own domain), and a single-IP exclusion expires after one year, or at once if spam comes from the IP.

For a ban by one website rather than a shared list, only that site can lift it: how to unblock an IP address.

For proxy users, IP reputation decides how many requests get a real page instead of a challenge. Three things matter:

• The IP type. Datacenter IPs sit in ranges that reputation databases label as hosting, so many sites challenge them on sight. Residential IPs belong to home internet providers and mobile IPs to carriers, and sites are slower to block them, because a block would also hit ordinary customers. The types compared: types of proxies.
• The subnet. Sites often block a whole /24 (256 addresses) or a whole provider network after abuse from a few IPs. A static list of proxies in one subnet can fail together; a pool spread over many networks does not.
• The history. An IP that someone else used for spam or attacks carries that record until it ages out, which is why the abuse policy of the provider matters as much as the size of its pool.

How to fix a flagged proxy IP:

ProxyField's residential gateway gives a new IP on every request (rotating), or keeps one IP for a sticky session of 30 seconds to 36 hours, and "if a node slows down, traffic automatically moves to the next one."

• Stay within the target's limits. Most scraping-related listings start with a site's own rate limit and a report to an abuse database. Pace requests and honor Retry-After: 429 Too Many Requests.
• Never send bulk mail from proxies or home IPs. Mail goes through an authenticated mail service with SPF, DKIM and DMARC set up.
• Keep devices patched, and watch outgoing traffic for spikes you did not cause.
• Follow your provider's rules. ProxyField's acceptable use policy forbids spam, attacks, password guessing and scanning without permission, the activities that put IPs on blocklists in the first place, and confirmed abuse leads to warnings, limits, suspension or closure of the account.

Spread your requests over residential IPs: ProxyField residential proxies cost $2.95/GB for 1 GB down to $1.95/GB from 1,000 GB, with no subscription. Start with the Easy Trial (1 GB); traffic never expires, and all purchases are final.

Checked on October 23, 2026 (the Spamhaus pages and return codes again on October 27, 2026):

• RFC 5782: DNS Blacklists and Whitelists (2010) and RFC 6598: Shared Address Space (2012).
• Spamhaus: ZEN, PBL, XBL, return codes, removal FAQ, reputation checker.
• AbuseIPDB FAQ; MXToolbox blacklist check.
• Cloudflare: Bot scores.