I've updated grepcidr again, adding some code contributed by a user. (This open source thing may actually have a future.) grepcidr is what it sounds like, you give it a bunch of CIDR ranges, and files to read, and it prints out the lines in the files that contain addresses that match any of the CIDR ranges. The new feature lets it match CIDR ranges in the input files as well as IP addresses. It handles both IPv4 and IPv6. It maps each file into memory and runs a state machine over the file in one pass so it's quite fast. There should be no limits on line length, file size, or number of patterns other than running out of memory. Find it here: http://www.taugh.com/grepcidr-2/ Regards, John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies", Please consider the environment before reading this e-mail. http://jl.ly