Name resolution (DNS, WINS, host files, etc.) can fail to convert an IP address into a host name.
General name resolution troubleshooting information:
Everything on the Internet uses IP addresses. A name resolution service (DNS, WINS, host files, etc.) is used to convert IP addresses into a human readable host name or fully qualified domain name.
When an incident has an IP address instead of a host name or domain name, it is because the name resolution service timed out or failed.
To diagnose the problem, get an IP address (IP) from an incident. Then on the Enforce server start a command line window and run the following commands. (The commands and output are very similar on Windows, Unix and Linux.)