I use eximstats to report my daily email traffic. I have a fairly high rate of rejections, and wanted hostnames listed in the rejection reports. To resolve this I developed a patch to capture the hostname related to the IP address, and add this data to the rejection reports.
The enhanced list saves me the effort of looking up IP addresses that were repeatedly addressed. Occasionally, these are from legitimate servers that have been misconfigured. DNS problems are often the cause. Continue reading