Groups | Search | Server Info | Login | Register

Groups > comp.compilers > #144

Re: Inverse grep

Show all headers | View raw

Actually, most "intrusion detection systems" (IDSes, e.g. Snort) and
virus scanners (e.g.  ClamAV) are essentially just that.  Given a
packet, the contents of the packet are inspected to see which if any
patterns are matched and if so, the relevant pattern [numbers] are
reported.  Generally, the technology used does not actually build a
single pattern from the | of the patterns and run that FA, because
there aren't known efficient solutions to that problem for large
pattern sets.  One either suffers space or time explosion to do so.

Hope this helps,
-Chris

******************************************************************************
Chris Clark                  email: christopher.f.clark@compiler-resources.com
Compiler Resources, Inc.  Web Site: http://world.std.com/~compres
23 Bailey Rd                 voice: (508) 435-5016
Berlin, MA  01503 USA      twitter: @intel_chris
[On machines with gigabyte memories, does the space explosion for
large patterns still matter? -John]

Back to comp.compilers | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Inverse grep glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2011-06-08 23:01 +0000
  Re: Inverse grep Chris F Clark <cfc@shell01.TheWorld.com> - 2011-06-12 14:16 -0400
    Re: Inverse grep Tony Finch <dot@dotat.at> - 2011-06-13 17:48 +0100
  Re: Inverse grep torbenm@diku.dk (Torben Ægidius Mogensen) - 2011-06-14 11:16 +0200
    Re: Inverse grep anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-06-15 12:28 +0000
    Matching very large patterns, was Re: Inverse grep Chris F Clark <cfc@shell01.TheWorld.com> - 2011-06-19 21:45 -0400
      Re: Matching very large patterns, was Re: Inverse grep glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2011-06-20 04:52 +0000

csiph-web