Performing a WHOIS and a Reverse DNS yields the following email addresses associated to their respective IP/CIDR Ranges:

PostMaster Comments

FastMail offers a feedback loop service, operated by Return Path, free of charge, to parties sending large amounts of mail to FastMail members. The feedback loop (FBL) will forward any mail reported as spam originating from the associated IP addresses back to the listed email address. We highly recommend the use of a dedicated e-mail address for this purpose.

A confirmation email will be sent to the contact email address you specify below. Once your request has been approved, Feedback Loop email will be sent to the email address listed in the "Feedback Loop Email" field.

To submit a request, you must agree to the Terms of Service .

Contact Information
* First Name:
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Feedback Loop Information
* Feedback Loop Email:		This is where Feedback Loop emails will go once your Feedback Loop is activated. (No auto-replies, please!)
* CIDRs/IPs:		List the CIDR's or IPs (one per line) that you want to receive Feedback Loop emails for. Individual IP addresses will be converted to their CIDR equivalent of x.x.x.x/32 Please collapse all IP's to CIDR when possible. For more information of CIDR ranges please Click here. CIDR ranges may be of /16 or higher.
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Your application for this feedback loop service is approved at the sole discretion of FastMail.