1) What are backscatters?

Backscatters are automatic replies such as bounce notifications, delivery notifications and absence notifications. If the sender of the original email is fake, it can sometimes happen that innocent third persons receive these automatic replies.

2) What is the backscatterer.org deny list?

backscatterer.org is a deny list collecting IPs that send bounce notifications, delivery notifications and absence notifications. Our customers send such bounce emails through us everyday.

3) Why are Hornetsecurity IP addresses listed by backscatterer.org?

If the recipient of an email uses backscatterer.org as a deny list, our outgoing IP addresses are put on this deny list when a bounce message is delivered.

4) Does Hornetsecurity take care that its IP addresses are delisted from the backscatterer.org deny list?

You send such bounce emails through us everyday. We, as your third party provider, are obliged to deliver these emails lawfully. Thus, Hornetsecurity does not regard these messages as spam.

Moreover, the operator of this deny list is not considered reputable because the operator demands a fee for delisting, regardless whether the sender actually disturbs the email traffic. For these reasons, Hornetsecurity does not ask for its IP addresses to be delisted from the backscatterer.org deny list.

5) What can a customer of Hornetsecurity do when his emails are rejected because of the backscatterer.org deny list?

Anyone who uses this deny list to reject emails, without having an allow list to soften the consequences of the inevitable "false positives", accepts either on purpose or accidentally that legitimate emails will not reach him. The communication partner should not use the backscatterer.org deny list as the sole criterion for classification.

The configuration of a mail server is the sole duty of its operator. Hornetsecurity can only give advice to the operator of the mail server concerned. We advise the customer to contact the communication partner.