--- title: Private Blocklists description: This article explains private blocklists and complaint feedback loops. --- [Skip to content](https://knowledgebase.mxtoolbox.com/home/what-are-private-blocklists#main-content) [Request Support](https://knowledgebase.mxtoolbox.com/home/kb-tickets/new?hsLang=en) [![](https://knowledgebase.mxtoolbox.com/hs-fs/hubfs/logo.gif.png?width=110&height=27&name=logo.gif.png)](https://mxtoolbox.com/) - [Help Knowledgebase](https://knowledgebase.mxtoolbox.com/home/) - [Delivery Center Home](https://delivery.mxtoolbox.com/) - [Monitoring Home](https://mxtoolbox.com/monitoring) - [DMARC Knowledgebase](https://mxtoolbox.com/DMARC/knowledgebase) - [Status Page](https://mxtoolbox.statuspage.io/) Open main navigation Close main navigation - [Help Knowledgebase](https://knowledgebase.mxtoolbox.com/home/) - [Delivery Center Home](https://delivery.mxtoolbox.com/) - [Monitoring Home](https://mxtoolbox.com/monitoring) - [DMARC Knowledgebase](https://mxtoolbox.com/DMARC/knowledgebase) - [Status Page](https://mxtoolbox.statuspage.io/) - [Request Support](https://knowledgebase.mxtoolbox.com/home/kb-tickets/new) How can we help you? - There are no suggestions because the search field is empty. 1. [MxToolbox Help Center](https://knowledgebase.mxtoolbox.com/home?hsLang=en) 2. [Delivery Center](https://knowledgebase.mxtoolbox.com/home/delivery-center?hsLang=en) 3. [Blocklist Monitoring](https://knowledgebase.mxtoolbox.com/home/delivery-center?hsLang=en#blocklist-monitoring) # Private Blocklists ## This article explains private blocklists and complaint feedback loops. In addition to 100+ public blocklists, there are several private and postmaster blocklists that can impact email delivery to recipients using clients such as Gmail, Yahoo, AOL, etc. If you find your domain or IP listed on one of these lists, it is likely that all email sent to recipients using that client will no longer receive your email until your reputation and complaint rates improve. Also, some of these lists are different from public blacklists because they provide Email Feedback Loops, also known as Complaint Feedback Loops. These feedback loops are provided to senders with the aim of helping them reduce spam complaint rates. Each feedback loop offers senders the ability to have complaints that each client receives forwarded to them as a means to understand how recipients feel about sender's email messages and take action in reducing the volume of spam complaints those emails generate. [Click here to access your Blocklist Monitoring feature.](https://delivery.mxtoolbox.com/#!/inbox_delivery_blacklist) ### Private Blocklists Below are examples of private blocklists. Click on the headers for specific information about each private blocklist. #### [AOL Postmaster Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_aol_postmaster_blocklist) #### [AT&T Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_att) #### [Cloudmark Sender Intelligence IP Reputation Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_cloudmark_sender_intelligence_ip_reputation) #### [Comcast Postmaster Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_comcast_postmaster) #### [Cox Communications Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_cox_communications) #### [Cyren Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_cyren) #### [Earthlink Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_earthlink) #### [Fortiguard IP Reputation Service](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_fortiguard_ip_reputation_service) #### [Gmail Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_gmail) #### [Office 365 Blocked Senders List](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_office_365_blocked_senders_list) #### [Proofpoint Dynamic Reputation Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_proofpoint_dynamic_reputation) #### [Return Path Reputation Network Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_return_path_reputation_network) #### [SenderBase Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_senderbase) #### [SophosLabs IP Address Classification List](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_sophoslabs_ip_classification) #### [Symantec Mail Security Reputation Blocklist](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_symantec_mail_security_reputation) #### [Trend Micro Email Reputation Service](https://delivery.mxtoolbox.com/#!/help/private_blocklists?key=private_blocklist_trend_micro_email_reputation_service) #### [Yahoo! 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