Troubleshooting feedback loop (FBL) request delays pending with Comcast

Under some circumstances when you apply to Comcast for a new feedback loop (FBL) or request modifications to an existing FBL, Comcast may:

  • Keep the request in a pending status for a long time
  • Disallow re-submission of the request until it is denied by Return Path 

Common scenarios
Comcast may delay approval of a new FBL or a modification request if:

  • The submission was made using ranges greater than /32 Classless Inter-Domain Routing (CIDR)
  • The IP addresses do not have a proper reverse Domain Name System (rDNS) set-up

Data needed to troubleshoot
You need:

  • The IP address
  • The FBL email address
  • The confirmation email address

To resolve the delay:

  1. Check the rDNS record entry of the IP address at the IP check for Mailservers website to make sure you have a fully qualified rDNS entry.

If necessary, correct the rDNS record.

  1. Open a support ticket with Return Path.

Return Path reviews:

  • The rDNS entry
  • The IP address range from the original FBL request
  1. If:
  • Both are correct, Return Path approves the FBL request.
  • The original request was for ranges greater than /32 CIDR, Return Path denies the original request and asks you to resubmit it using the appropriate range.
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