grepcidr can filter IP addresses matching IPv4 CIDR/network specification.
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.
grepcidr has endless uses in network software, including: mail filtering and processing, network security, log analysis, and many custom applications.
COMMAND USAGE
grepcidr [-V] [-c] [-v] PATTERN [FILE]
grepcidr [-V] [-c] [-v] [-e PATTERN | -f FILE] [FILE]
-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
PATTERN specified on the command line may contain multiple patterns
separated by whitespace or commas. For long lists of network patterns,
specify a -f FILE to load where each line contains one pattern. Comment
lines starting with # are ignored, as are any lines that don't parse.
Each pattern, whether on the command line or inside a file, may be:
CIDR format a.b.c.d/xx
IP range a.b.c.d-e.f.g.h
Single IP a.b.c.d
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
What's New in This Release:
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