NAME

       grepcidr — Filter IP addresses matching IPv4 CIDR/network specification

SYNOPSIS

       grepcidr [-V]  [-c]  [-v]  [-e pattern | -f file]

DESCRIPTION

       This manual page documents briefly the grepcidr command.

       This manual page was written for the Debian distribution because the original program does
       not have a manual page.

       grepcidr can be used to filter a list of IP addresses against one or more Classless Inter-
       Domain Routing (CIDR) specifications, or arbitrary networks specified by an address range.
       As with grep, there are options  to  invert  matching  and  load  patterns  from  a  file.
       grepcidr is capable of comparing thousands or even millions of IPs to networks with little
       memory usage and in reasonable computation time.

OPTIONS

       -V        Show software version

       -c        Display count of the matching lines, instead of showing the lines

       -v        Invert the sense of matching, to select non-matching IP addresses

       -e        Specify pattern(s) on command-line

       -f        Obtain CIDR and range pattern(s) from file

EXAMPLES

       grepcidr -f ournetworks blocklist > abuse.log

       Find our customers that show up in blocklists

       grepcidr 127.0.0.0/8 iplog

       Searches for any localnet IP addresses inside the iplog file

       grepcidr "192.168.0.1-192.168.10.13" iplog

       Searches for IPs matching indicated range in the iplog file

       script | grepcidr -vf whitelist > blacklist

       Create a blacklist, with whitelisted networks removed (inverse)

       grepcidr -f list1 list2

       Cross-reference two lists, outputs IPs common to both lists

AUTHOR

       This manual page was written by Ryan Finnie ryan@finnie.org for the Debian system (but may
       be used by others).  Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU General Public License, Version 2 any later  version  published
       by the Free Software Foundation.

       On  Debian  systems,  the  complete text of the GNU General Public License can be found in
       /usr/share/common-licenses/GPL.

                                                                                      GREPCIDR(1)