IP Blacklist (IP Blocklist)

An IP blacklist, more often called an IP blocklist today, is a list of IP addresses that a network, service or security provider has decided to refuse or restrict. Addresses usually land on one after reports of spam, attacks, abusive traffic or request volumes a site considers excessive.

For anyone collecting web data, a blocklist entry usually shows up as an access error. Diagnosing it correctly tells you whether you're dealing with a one-site decision, a shared-IP problem or a wider reputation issue, and who can resolve it.

Types of blocklists

Each list has its own criteria, duration and removal process. Being listed in one place says little about another.

How a block shows up

• 403 Forbidden. The server understood the request and refused it. CDNs often return a block page with a reference ID; Cloudflare's Error 1020, for example, means a security rule configured by the site owner blocked the request.
• Connection refused, reset or timing out. Some firewalls drop traffic from listed addresses before any HTTP response.
• Challenge pages. The site asks for confirmation that a person is visiting.
• 429 Too Many Requests. This is rate limiting, not a blocklist. It means slow down, and it often comes with a Retry-After header. Repeated 429s that are ignored can lead to a block.

How to verify a listing

1. Confirm the IP you're using. Your public IP may differ from what you expect behind a VPN, office network, cloud host or proxy.
2. Check public reputation tools. Spamhaus and AbuseIPDB show whether an address appears in their data. AbuseIPDB rates confidence of abuse on a 0–100 scale based on user reports.
3. Check whether the problem is one site or many. A refusal from a single site is usually that site's rules. Failures across unrelated services point to a reputation list or a network issue.
4. Consider shared addresses. Office networks, mobile carriers using CGNAT, cloud hosts and proxies share IPs between many users, so a listing can come from someone else's traffic.
5. Review your own traffic. Look at request rate, concurrency, retries and error logs for the period before the block.

How to resolve it

If you operate the IP. Find and fix the cause first: a compromised device, a misconfigured job, an unthrottled retry loop or excessive concurrency. Then follow the list's own removal process. Most lists relist addresses that keep sending the same traffic.

If your provider operates the IP. Contact your hosting, cloud or proxy provider. They control the address, can investigate abuse reports and can request delisting or assign a different address under their own policies.

If a specific site blocked you. Contact the site owner. Include the reference ID or Ray ID from the block page, the time, your IP and a short description of what you're collecting and why. Ask whether they offer an API, a data feed or an allowlist for approved access.

Blocks and authorization

A site blocking your traffic is a decision about access to its service. Switching IP addresses or networks to keep sending the same requests doesn't resolve that decision. It can breach the site's terms and, depending on the circumstances, applicable law.

MrScraper's Acceptable Use Policy prohibits handling the authentication or security of any host, network or account. If a site blocks your collection, stop and ask for approved access.

Monitoring for blocks in MrScraper

Each MrScraper Web Fetching response reports the target site's status code in an x-status-code header. Alert on rising 403 or 429 responses and pause the job before a site escalates. Use scheduling to collect at a pace that matches how often the data actually changes.

Frequently asked questions

How do I check if my IP is blacklisted?

Look up the address in public reputation tools such as Spamhaus or AbuseIPDB, then check whether the errors happen on one site or many. A single-site block won't appear in public lists.

How long does an IP stay on a blocklist?

It depends on the list. Some entries expire automatically, some need a removal request, and site-level blocks last as long as the site owner keeps the rule.

Can I get my IP removed from a blocklist?

Usually, if you control the address and have fixed the cause. Use the list's removal process, or ask your provider if they own the IP. For a site-level block, only the site owner can lift it.

Will a VPN or proxy fix a blocked IP?

A different IP doesn't change why you were blocked. If one site refused your traffic, ask that site for access. If your own IP is listed for abuse, fix the cause and request removal.

What's the difference between a blacklist and a whitelist?

A blocklist refuses listed addresses. An allowlist (whitelist) admits only listed addresses, and site owners can use one to grant approved partners access.