Sometimes a website will not load, your email keeps landing in spam, or you see a CAPTCHA every few minutes. A common cause is that your IP address is on a blocklist (blacklist). This article explains how to tell whether the IP is the problem and what you can do.
What does a blacklisted IP mean?
Security companies and anti-spam services keep lists of IP addresses that have shown suspicious behaviour: sending spam, attacks, port scanning or bot traffic. When your IP is on those lists, sites and mail servers may throttle or block you — even if you did nothing wrong.
Why does "my" IP get blacklisted?
- Shared IP (CGNAT): hundreds of users sit behind one public address, so one person's bad behaviour affects everyone.
- Dynamic IP: the address assigned to you today belonged to someone else yesterday, who may have sent spam.
- Busy VPN server: if a VPN is on, the exit IP is shared by many users and is often already listed. See how a VPN changes your IP.
- Infected device on the network: a malware-infected machine on your home or office network can send bad traffic from your shared IP.
- Bulk email: for server owners, sending newsletters badly gets the server IP blocked quickly.
How to check whether an IP is blacklisted
- Find your IP: open the Show-IP.ir home page. The "security status" section shows whether your IP is known as a proxy, Tor, datacenter or threat — that is the first clue.
- Search a few reputation services: IP reputation and DNSBL lookups tell you which lists an address is on.
- Spot the pattern: if only email is affected, it is likely a mail blacklist (DNSBL). If every site shows a CAPTCHA, it is a general reputation blocklist.
How to get off a blocklist
- Change your IP: the simplest fix for a home user — power off the modem for a few minutes to get a new address if your IP is dynamic.
- Turn off the VPN or switch its server if the exit IP is the source.
- Scan your devices for malware.
- Request delisting: most reputable lists have a removal form, but you will be re-added unless the root cause is fixed.
- Contact your ISP if a whole ISP block is listed — only they can act.
- For a mail server: set up SPF, DKIM and DMARC correctly and lower your send rate.
Is the IP really the problem?
A quick test: open the same site on mobile data (a different IP). If it works on mobile but not on your home connection, your home IP is probably restricted. If it fails on both, the cause is elsewhere (DNS, filtering, or the site itself).
Key takeaways
- Frequent CAPTCHAs, email going to spam and some sites not loading are signs of a blacklisted IP.
- Shared IPs (CGNAT) and busy VPN servers are the most common causes.
- The "security status" section on the home page is the fastest first check.
- Testing on mobile data shows whether the IP is at fault.
- Without fixing the root cause, delisting is only temporary.