The IP address 255.255.255.255 appears in the following reports even if they are filtered to show outbound traffic only:

• Top Sender HELO Domains
  All Top Sender HELO Domain reports are affected

• Top Sender IP Connections
  All Top Sender IP Connections reports are affected

• Top Succeeded Connections SMTP report

• Top Failed Connections SMTP report

• Top Rejected Connections SMTP report

The process of IP selection described in the "Sender HELO domain or IP connection shows gateway information" issue of the "Table: Report data details" section of the article HOWTO53390 is applied to all messages regardless of direction.

The IP address of 255.255.255.255 is used to indicate that the receive headers could not be parsed successfully.

This is by design.