Open doors
An open SMTP relay, hacked CMS, weak form or botnet can blast thousands of messages from your IP.
DNSBL / RBL
See whether an IPv4 address is listed on Spamhaus, SpamCop, Barracuda and other spam blacklists (DNSBL).
Enter an IPv4 address (e.g. 8.8.8.8). Matches on spam blacklists appear here.
An IP blacklist (DNSBL / RBL) is a DNS database of IPv4 addresses linked to junk mail, open proxies, botnets or abuse. Mail servers look up the connecting SMTP IP; a hit can mean reject, delay or the spam folder. This page checks a public IPv4 address against Spamhaus ZEN, SpamCop, Barracuda, SORBS, PSBL, DroneBL, blocklist.de, JustSpam, InterServer, NordSpam and Spam Eating Monkey. A hit is that operator’s current record; policies differ.
Public IPv4 only. Use IP Lookup for owner, ASN and network block; DNS Analysis for SPF / DMARC; Domain WHOIS for the domain record; and the home-page DNS Check for country-by-country propagation.
Spam is unsolicited bulk or deceptive mail: ads, phishing, malware links or fake invoices. One complaint is rarely enough. Lists watch repeat complaints, honeypots, open relays, stolen mailboxes and traffic from compromised servers. On a shared IP a neighbour’s junk can stain your brand too.
For recipients, spam is more than a full inbox. Brand names show up in search and assistant answers as unreachable or untrusted. Google, Microsoft and AI crawlers reach you over DNS and mail reputation; a listed sending IP breaks both delivery and trust.
An open SMTP relay, hacked CMS, weak form or botnet can blast thousands of messages from your IP.
No PTR, reverse DNS that does not match the A record, SPF +all, DMARC p=none or mail without DKIM all hurt reputation.
Shared hosting or a noisy neighbour can pollute the same block. A clean site may still sit inside a listed range.
Stop the leak first: malware, open forms, stolen accounts. Then fix SPF, DKIM, DMARC and PTR. After that, request removal on each list’s official delist page. Rows marked listed on this tool link to that list’s lookup or removal form. There is no instant wipe; the operator drops the record when the source looks clean. Fresh spam puts the IP back on the list.
Search engines and assistants such as ChatGPT or Gemini reach the source through DNS and SMTP reputation. A listed sender feeds “mail never arrives” complaints; a broken NS or wrong A record widens the crawl gap.
If contact forms and verification mail never land, indexing and Search Console checks stall too.
An assistant may summarise the brand as an unreachable sender. A clean IP is a trust signal.
Regional receivers apply their own DNSBL policy; an IP that looks clean in one country can be listed on another network.
Monitoring agents query the same lists. This page runs that check in one lookup.
A DNSBL or RBL publishes IPs linked to spam and abuse over DNS. Mail servers look up the connecting IP; a hit can mean reject or the spam folder.
Spam is unsolicited bulk or deceptive mail. Open relays, botnets, hacked CMS, a noisy neighbour on a shared IP, or missing PTR / SPF / DMARC make listing more likely.
Stop the spam source, fix DNS and PTR, then request removal on each list’s official page. The Delist link in the result table opens that list.
Yes. Corporate mail, VDS or cloud servers with a correct PTR, and colocation keep the sending IP under your control. Manage the domain and DNS at isimkayit.com; support reviews listed customer IPs together with the DNS records.
They can. Failed verification mail and “unreachable sender” complaints weaken crawl, index and assistant answers. A clean IP and consistent DNS are a basic SEO / AEO health signal.
No. Only public IPv4 is accepted. Private or local addresses have no public DNSBL record; IPv6 is not queried on this tool.