This page was designed to address questions on the following topics:
What do I need to know to avoid blocks when sending to Comcast?
What do I need to know to avoid blocks when sending to Comcast over IPv6?
What are Comcast's outbound mail servers?
IP and host names for Comcast's outbound mail servers.
What are Comcast's mail delivery error messages?
An index of all Comcast's error messages resulting from failed delivery attempts.
What are Comcast's dynamic IP ranges?
A list of Comcast's dynamic IP space.
How do I get my IP block removed?
An automated way to remove many blocks. Please read the FAQs to ensure this is a block our form will remove.
How do I sign up for Comcast's feedback loop?
Requirements before signing up for Comcast's feedback loop program.
All policies and thresholds on this page are subject to change. This site will be updated when such changes are implemented.