I was having the same issue. After some searching I found that the nfdump doesn't fully support Cisco ASAs in the current stable branches. The only branch that supports ASAs is the NSEL branch. See the sourceforge page here: http://sourceforge.net/projects/nfdump/. "For CISCO ASA devices, which export Netflow Security Event Loging (NSEL) records, please use nfdump-1.5.8-2-NSEL." ... View more