flowscan 1.006-13.2 / usr / share / doc / flowscan / pod / UserManual.pod

=head1 NAME

FlowScan - a system to analyze and report on cflowd flow files

=head1 DESCRIPTION

This document is the FlowScan User Manual $Revision: 1.23 $, $Date: 2001/02/28 21:48:08 $.
It describes the installation and setup of C<FlowScan-1.006>.

FlowScan is a system which scans cflowd-format raw flow files and
reports on what it finds.  There are two report modules that are
included.  The C<CampusIO> report module produced the graphs at:

   http://wwwstats.net.wisc.edu

which show traffic in and out through a peering point or network
border.  The C<SubNetIO> report updates RRD files for each of the
subnets that you specify (so that you can produce graphs of C<CampusIO>
by subnet).

The idea behind the distinct report modules is that users will be able
to write new reports that are either derived-classes from C<CampusIO>
or altogether new ones.  For instance, one may wish to write a report
module called C<Abuse> which would send email when it detected
potentially abusive things going on, like Denial-of-Service attacks and
various scans.

FlowScan is freely-available under the GPL, the GNU General Public
License.

=head1 Use the Mailing List

Please help me to help you.  It is, unfortunately, not uncommon for one
to have questions or problems while installing FlowScan.  Please do not
send email about such things to my personal email address, but instead
check the FlowScan mailing list archive, and join the FlowScan mailing
list.  Information about the FlowScan mailing lists can be found at:

   http://net.doit.wisc.edu/~plonka/FlowScan/#Mailing_Lists

By reading and participating in the list, you will be helping me to use
my time effectively so that others will benefit from questions answered
and issues raised.

The mailing lists' archives are available at:

   http://net.doit.wisc.edu/~plonka/list/flowscan

and:

   http://net.doit.wisc.edu/~plonka/list/flowscan-announce

=head1 Upgrading

B<First-time> FlowScan users should skip to L<Initial Install Requirements>,
below.

If you have previously installed and properly configured
C<FlowScan-1.005>, you need only perform a subset of the steps that one
would normally have to perform for an initial installation.

This release of FlowScan uses more memory than previous releases.  That
is, the C<flowscan> process will grow to a larger size than that in
C<FlowScan-1.005>.  In my recent experience while testing this release,
the C<flowscan> process size to approximately 128MB when I use the new
experimental C<BGPDumpFile> option to produce "Top" reports by ASN.
This is hopefully understandable since C<flowscan> is carrying a full
internet routing table when configured in this way.  The memory
requirements are significantly lessened if you do not use the
C<BGPDumpFile> option.  The C<flowscan> process' size is also a
function of the number of active hosts in your network.

=head2 Software Upgrade Requirements

=over 4

=item * Upgrading perl Modules

Upgrade the C<Cflow> perl module to C<Cflow-1.030> or later for
improved performance.  Install C<HTML::Table> in case you want to
produce the new "Top Talkers" reports.  Details on how to obtain and
install these modules can be found in L<Software Requirements>, below.

=item * Upgrading FlowScan

Of course, when upgrading you will need to obtain the current
FlowScan.  When you run F<configure>, you should specify the same value
with C<--prefix> that you did when installing your existing FlowScan,
e.g.  F</var/local/flows>, or wherever your time-stamped raw flow files
are currently being written by C<cflowd>.

=back

=head2 Configuring FlowScan when Upgrading

There is now POD documentation provided with the CampusIO and SubNetIO
reports.  Please use that as the definitive reference on configuration
options for those reports, e.g.:

   $ cd bin
   $ perldoc CampusIO

Here are a few things that changed regarding the FlowScan configuration:

=over 4

=item Upgrading CampusIO and/or SubNetIO Configuration Files

There are new C<TopN> and C<ReportPrefixFormat> directives for
C<CampusIO> and C<SubNetIO>.  These directives enable the production of
"Top Talker" reports.  Furthermore there are new B<experimental>
C<BGPDumpFile> and C<ASNFile> options C<CampusIO> which are used to
produce "Top" reports by Autonomous System.  You will need access a
Cisco carrying a full BGP routing table to produce such reports.  See
the CampusIO configuration documentation for more info about
configuring this feature.  If you have trouble with it, remember that
it is experimental, so please join the discussion in the mailing list.

Secondly, the F<Napster_subnets.boulder> has changed significantly
since that provided with FlowScan-1.005.  If you have FlowScan
configured to measure Napster traffic, replace your old
F<Napster_subnets.boulder> with the one from the newer distribution:

   $ cp cf/Napster_subnets.boulder $PREFIX/bin/Napster_subnets.boulder

=item Upgrading your RRD Files

If you are upgrading, it is necessary to add two new Data Sources to
the some of your existing RRD files.  Before running flowscan, backup
your RRD files, e.g.:

   $ cd $prefix/graphs
   $ tar cf saved_rrd_files.tar *.rrd

then do this:

   $ cd $prefix/graphs
   $ ../bin/add_txrx total.rrd [1-9]*.*.*.*_*.rrd

=back

=head2 Generating Graphs after Upgrading

A number of new features have been added to the F<graphs.mf> template
Makefile.   Some of these are described below in L<Supplied Graphs>.
You may wish to copy F<graphs.mf> to your F<graphs>
sub-directory.

While it is not required, I highly recommend installing C<RRGrapher> if
you want to produce other graphs.  It is referenced below in L<Custom
Graphs>.

=head2 Done Upgrading 

That should be it for upgrading!

=head1 Initial Install Requirements

=head2 Hardware Requirements

=over 4

=item * Cisco routers

If you don't have Cisco at your border, you're probably barking up
the wrong tree with this package.  Also, FlowScan currently requires
that your IOS version supports NetFlow version 5.  Try this command
on your router if you are unsure:

   ip flow-export version ?

=item * a GNU/Linux or Unix machine

If you have a trivial amount of traffic being exported to cflowd,
such as a T1's worth, perhaps any old machine will do.

However, if you want to process a fair amount of traffic (e.g. at
~OC-3 rates) you'll want a I<fast> machine.

I've run FlowScan on a SPARC Ultra-30 w/256MB running Solaris 2.6, a
Dell Precision 610 (dual Pentium III, 2x450Mhz) w/128MB running Debian
Linux 2.1, and most recenlty a dual PIII Dell server, 2x600Mhz, w/256MB
running Debian Linux 2.2r2.  The Intel machines are definitely
preferably in the sense that C<flowscan> processes flows in about 40%
of the time that it took the SPARC.  (The main C<flowscan> script
itself is currently single-threaded.)

In an early performance test of mine, using 24 hours of flows from
our peering router here at UW-Madison, here's the comparison of
their ave. time to process 5 minutes of flows:

   SPARC - 284 sec
   Intel - 111 sec

Note that it is important that flowscan doesn't take longer to
process the flows than it does for your network's activity and
exporting Cisco routers to produce the flows.  So, you want to
keep the time to process 5 minutes of flows under 300 seconds on
average.

My recent testing has indicated that 600-850MHz PIII machines can
usually process 3000-4000 flows per second, if C<flowscan> doesn't
have to compete with too many other processes.

=item * Disk Space

I recommend devoting a file-system to cflowd and FlowScan.  Both
require disk space and the amount depends upon a number of things:

=over 4

=item * The rate of flows being exported and collected

=item * The rate at which FlowScan is able to process (and remove) those files

=item * Whether or not you have configured FlowScan to "save" flow files

=item * The number of hours after which you remove C<gzip(1)>ped flow files

=back

To find the characteristics of your environment, you'll just have to
run the patched cflowd for a little while to see what you get.

Early in this project (c. 1999), we were usually collecting about
150-300,000 flows from our peering router every 5 minutes.  Recently,
our 5-minute flow files average ~15 to 20 MB in size.

During a recent inbound Denial-of-Service attack consisting of 40-byte
TCP SYN packets with random source addresses and port numbers, I've
seen a single "5-minute" flow file greater than 500MB! Even on our fast
machine, that single file took hours to process.

Surely YMMV, currently a 35GB file-system allows us to preserve
C<gzip(1)>ped flow files for about 2 weeks.

=item * Network Interface Card

Regarding the host machine configuration, consider the amount of
traffic that may be exported from your Cisco(s) to your collector
machine if you have enabled C<ip route-cache flow> on very many fast
interfaces.  With lots of exported flow data (e.g. 15-20 MB of raw flow
file data every 5 minutes) and only a 10 Mb/s ethernet NIC, I found
that the host was dropping some of the incoming UDP packets, even
though the rate of incoming flows was less than 2 Mb/s.  This was
evidenced by a constantly-increasing number of C<udpInOverflows> in the
C<netstat -s> output under Solaris.  I addressed this by reconfiguring
my hosts with a 100 Mb/s fast ethernet NIC or 155 Mb/s OC-3 ATM LANE
interface and have not seen that problem since.  Of course, one should
assure that the requisite bandwidth is available along the full path
between the exporting Cisco(s) and the collecting host.

=back

=head2 Software Requirements

The packages and perl modules required by FlowScan are numerous.  Their
presence or absence will be detected by FlowScan's F<configure> script
but you'll save yourself some frustration by getting ahead of the game
by collecting and installing them first.  Below, I've attempted to
present them in a reasonable order in which to obtain, build, and
install them.

=over 4

=item * arts++

arts++ is required by cflowd and is available at:

   ftp://ftp.caida.org/pub/arts++/

As of arts++-1-1-a5, the arts++ build appears to require GNU make 3.79
because its Makefiles use glob for header dependencies, e.g. "*.hh".
From my cursory look at the GNU make ChangeLog, perhaps any version >=
3.78.90 will suffice.  Also there may be trouble if you don't have flex
headers installed in your "system" include directory, such as
"/usr/include", even though "configure.in" appears to be trying to
handle this situation.  Since mine were in the "local" include
directory, I hand-tweaked the classes/src/Makefile's ".cc.o" default
rule to include that directory as well.

=item * cflowd patch

My patches are available at:

   http://net.doit.wisc.edu/~plonka/cflowd/?M=D

Obtain the patch or patches which apply to the version of cflowd that
you intend to run and apply it to cflowd before building cflowd below.

=item * cflowd

cflowd itself is available at:

   http://www.caida.org/tools/measurement/cflowd/
   ftp://ftp.caida.org/pub/cflowd/

In my experience with building cflowd, you're the most likely to
have success in a GNU development environment such as that provided
with GNU/Linux or FreeBSD.

I have not had problems building the patched C<cflowd-2-1-a9> or
C<cflowd-2-1-a6> under Debian Linux 2.2.

I've also managed to build the patched cflowd-2-1-a6 with gcc-2.95.2
and binutils-2.9.1 on a sparc-sun-solaris2.6 machine with GNU make 3.79
and flex-2.5.4.

As of cflowd-2-1-a6, beware that during the build may pause for minutes
while as(1) uses lots of CPU and memory to building "CflowdCisco.o".
This is apparenly `normal'. Also, the build appears to be subtley
reliant on GNU ld(1), which is available in the GNU "binutils" package.
(I was unable to build cflowd-2-1-a6 with the sparc-sun-solaris2.6
"/usr/ccs/bin/ld" although earlier cflowd releases built fine with it.)

=item * perl 5

If you don't have this already, you're probably way over your head,
but anyway, check out the Comprehensive Perl Archive Network (CPAN):

   http://www.cpan.org/

and:

   http://www.perl.com/

I've tested with perl 5.004, 5.005, and 5.6.0.
If you'd like to upgrade to perl 5.6.0 you can install it thusly:

   # perl -MCPAN -e shell
   cpan> install G/GS/GSAR/perl-5.6.0.tar.gz

However, I suggest you don't install it in the same place as your
existing C<perl>.

=item * Korn shell

C<ksh> is used as the C<SHELL> in the F<Makefile> for the graphs.
C<pdksh> works fine too.  If for some reason you don't already have
C<ksh>, check out:

   http://www.kornshell.com/

or:

   http://www.math.mun.ca/~michael/pdksh/

If you're using GNU/Linux, C<pdksh> is available as an optional binary
package for various distributions.

=item * RRDTOOL

This package is available at:

   http://ee-staff.ethz.ch/~oetiker/webtools/rrdtool/

I recommend that you install C<rrdtool> from source, even if it is
available as an optional binary package for operating system
distribution.  This is because FlowScan expects that you've built and
installed RRDTOOL something like this:

   $ ./configure --enable-shared
   $ make install site-perl-install

That last bit is important, since it makes the C<rrdtool> perl modules
available to all perl scripts.

=item * Perl Modules

=over 4

=item * C<RRDs>

This is the shared-library perl module supplied with C<rrdtool>. (See above.)

=item * C<Boulder>

The Boulder distribution includes the Boulder::Stream module and its
prerequisites.  They are available on CPAN in the "Boulder"
distribution.

You can install them using the CPAN shell like this:

   # perl -MCPAN -e shell
   cpan> install Boulder::Stream

If you want to fetch it manually you can probably find it at:

   http://search.cpan.org/search?dist=Boulder

I've tested with the modules supplied in the Boulder-1.18 distribution
and also those in the old "boulder.tar.gz" distribution.

=item * C<ConfigReader::DirectiveStyle>

The ConfigReader package is available on CPAN.
You can install it using the CPAN shell like this:

   # perl -MCPAN -e shell
   cpan> install ConfigReader::DirectiveStyle

If you want to fetch it manually you can probably find it at:

   http://search.cpan.org/search?dist=ConfigReader

I'm using ConfigReader-0.5.

=item * C<HTML::Table>

The HTML::Table package is available on CPAN.
You can install it using the CPAN shell like this:

   # perl -MCPAN -e shell
   cpan> install HTML::Table

If you want to fetch it manually you can probably find it at:

   http://search.cpan.org/search?dist=HTML-Table

=item * C<Net::Patricia>

This is a new module which I have uploaded to PAUSE, but it not have
entered CPAN yet.

You can try to install it using the CPAN shell like this:

   # perl -MCPAN -e shell
   cpan> install Net::Patricia

If C<Net::Patricia> is not found on CPAN, you can obtain it here:

   http://net.doit.wisc.edu/~plonka/Net-Patricia/

=item * C<Cflow>

This perl module is used by FlowScan to read the raw flow files written
by cflowd.  It is available at:

   http://net.doit.wisc.edu/~plonka/Cflow/

You'll need Cflow-1.024 or greater.

=item * FlowScan

This package is available at:

   http://net.doit.wisc.edu/~plonka/FlowScan/

=back

=back

=head1 Configuring FlowScan Prerequisites

=head2 Choose a User to Run cflowd and FlowScan

I recommend that you create a user just for the purpose of running
these utilities so that all directory permissions and created file
permissions are consistent.  You may find this useful especially if you
have multiple network engineers accessing the flows.

I suggest that the FlowScan C<--prefix> directory be owned by an
appropriate user and group, and that the permissions allow write by
other members of the group.  Also, turn on the set-group-id bit on the
directory so that newly created files (such as the flow files and log
file) will be owned by that group as well, e.g.:

   user$ chmod g+ws $PREFIX

=head2 Configuring Your Host

The current FlowScan graphing stuff likes your machine to have the
C<80/tcp> service to be called C<http>.  Try running this command:

   $ perl -le "print scalar(getservbyport(80, 'tcp'))"

You can continue with the next step if this command prints C<http>.
However, if it prints some other value, such as C<www>, then I suggest
you modify your F</etc/services> file so that the line containing
C<80/tcp> looks something like this:

   http             80/tcp    www www-http         #World Wide Web HTTP

Be sure to leave the old name such as C<www> as an "alias", like I've
shown here.  This will reduce the risk of breaking existing
applications which may refer to the service by that name.  If you
decide not to modify the service name in this way, FlowScan should
still work, but you'll be on your own when it comes to producing
graphs.

=head2 Configuring Your Ciscos

First and foremost, to get useful flow information from your Cisco,
you'll need to enable flow-switching on the appropriate ingress interfaces
using this interface-level configuration statement:

   ip route-cache flow

Also, I suggest that you export from your Cisco like this:

   ip flow-export version 5 peer-as
   ip flow-export destination 10.0.0.1 2055

Of course the IP address and port are determined by your
F<cflowd.conf>.  To help ensure that flows are exported in a timely
fashion, I suggest you also do this if your IOS version supports it:

   ip flow-cache timeout active 1

Some IOS versions, e.g. 12.0(9), use this syntax instead:

   ip flow-cache active-timeout 1

unless you've specified something such as C<downward-compatible-config 11.2>.

Lastly, in complicated environments, choosing which particular interfaces
should have C<ip route-cache flow> enabled is somewhat difficult.
For FlowScan, one usually wants it enabled for any interface that is
an ingress point for traffic that is from inside to outside or vice-versa.
You probably don't want flow-switching enabled for interfaces that carry
policy-routed traffic, such as that being redirected transparently to a
web cache.  Otherwise, FlowScan could count the same traffic twice because
of multiple flows being reported for what was essentially the same traffic
making multiple passes through a border router.  E.g. user-to-webcache,
webcache-to-outside world (on behalf of that user).

=head2 Configuring cflowd

This document does not attempt to explain cflowd.  There is good
documentation provided with that package.

As for the tweaks necessary to get cflowd to play well with FlowScan,
hopefully, an example is worth a thousand words.

My F<cflowd.conf> file looks like this:

   OPTIONS {
     LOGFACILITY:          local6
     TCPCOLLECTPORT:       2056
     TABLESOCKFILE:        /home/whomever/cflowd/etc/cflowdtable.socket
     FLOWDIR:              /var/local/flows
     FLOWFILELEN:          1000000
     NUMFLOWFILES:         10
     MINLOGMISSED:         300
   }
   CISCOEXPORTER {
     HOST:         10.0.0.10
     ADDRESSES:    { 10.42.42.10,
                   }
     CFDATAPORT:   2055
   #  COLLECT:      { flows }
   }
   COLLECTOR {
     HOST:         127.0.0.1
     AUTH:         none
   }

And I invoke the I<patched> cflowd like this:

   user$ cflowd -s 300 -O 0 -m /path/to/cflowd.conf

Those options cause a flow file to be "dropped" every 5 minutes,
skipping flows with an output interface of zero unless they are multicast
flows.  Once you have this working, your ready to continue.

=head1 Configuring FlowScan

=head2 Configure and Install

B<Do not> use the same C<--prefix> value as might for other packages!

I.e. don't use F</usr/local> or a similar directory in which other
things are installed.  This prefix should be the directory where the
patched cflowd has been configured to write flow files.

A good way to avoid doing something dumb here is to not run FlowScan's
C<configure> nor C<make> as root.

   user$ ./configure --help # note --with-... options

e.g.:

   user$ ./configure --prefix=/var/local/flows
   user$ make
   user$ make -n install
   user$ make install

By the way, in the above commands, all is OK if make says "C<Nothing to
be done for `target'>".  As long as C<make> completes without an
error, all is OK.

Subsequently in this document the "prefix" directory will be referred
to as the "C<--prefix> diretory" or using the environment variable
C<$PREFIX>.  FlowScan does not require or use this environment
variable, it's just a documentation convention so you know to use the
directory which you passed as with C<--prefix>.

=head2 Create the Output Directory

The C<OutputDir> is where the C<.rrd> files and graphs will reside.
As the chosen FlowScan user do:

  $ PREFIX=/var/local/flows
  $ mkdir -p $PREFIX/graphs

Then, when you edit the C<.cf> files below, be sure to specify this
using the C<OutputDir> directive.

=head2 FlowScan Configuration Files

The FlowScan Package ships with sample configuration files in the C<cf>
sub-directory of the distribution.  During initial configuration you
will copy and sometimes modify these sample files to match your network
environent and your purposes.

FlowScan looks for its configuration files in its C<bin> directory -
i.e. the directory in which the C<flowscan> perl script I<and> FlowScan
report modules are installed.  I don't really like this, but that's the
way it is for now.  Forgive me.

FlowScan currently uses two kinds of cofiguration files:

=over 4

=item 1 DirectiveC<-s>tyle configuration files, with the C<.cf> extension

This format should be relatively self-explanatory based on the sample
files referenced below.  The directives are documented in comments
within those sample configuration files.

A number of the directorives have paths to directory entries as their
values.  One has a choice of configuring these as either relative or
absolute paths.  The samples configuration files ship with relative
path specifications to minimize the changes a new user must make.
However, in this configuration, it is imperitive that C<flowscan> be
run in the C<--prefix> directory if these relative paths are used.

=item 2 "Boulder IO" format files, with the C<.boulder> extension

I've chosen Boulder IO's "semantic free data interchange format" to use
for related projects, and since this is the format in which our subnet
definitions were available, I continued to use it.

If you're new to "Boulder IO", the examples referenced below should be
sufficient.  Remember that lines containing just C<=> are record
seperators.

For complete information on this format, do:

   $ perldoc Boulder # or "perldoc bolder" if that fails

=back

Here's a step-by-step guide to installing, reviewing, and editing the
FlowScan configuration files:

=over 4

=item * Copy and Edit F<flowscan.cf>

  $ cp cf/flowscan.cf $PREFIX/bin
  $ chmod u+w $PREFIX/bin/flowscan.cf
  $ # edit $PREFIX/bin/flowscan.cf

=item * Decide which FlowScan Reports to Run

The FlowScan package contains the C<CampusIO> and C<SubNetIO> reports.
These two reports are mutually exclusive - C<SubNetIO> does everything
that C<CampusIO> does, and more.

Initially, in F<flowscan.cf> I strongly suggest you configure:

   ReportClasses CampusIO

rather than:

   ReportClasses SubNetIO

The C<CampusIO> report class is simpler than C<SubNetIO>, requires less
configuration, and is less CPU/processing intensive.  Once you have the
C<CampusIO> stuff working, you can always go back and configure
C<flowscan> to use C<SubNetIO> instead.

There is POD documentation provided with the C<CampusIO> and
C<SubNetIO> reports.  Please use that as the definitive reference on
configuration options for those reports, e.g.:

   $ cd bin
   $ perldoc CampusIO

=item * Copy and Edit F<CampusIO.cf>

Copy the template to the F<bin> directory.  Adjust the values using the
required and optional configuration directives documented there-in.

The most important thing to consider configuring in F<CampusIO.cf> is
the method by which C<CampusIO> should identify outbound flows.  In
order of preference, you should define C<NextHops>, or
C<OutputIfIndexes>, or neither.  Beware that if you define neither,
CampusIO will resort to using the flow destination address to determine
whether or not the flow is outbound.  This can be troublesome if you do
not accurately define your local networks (below), since flows
forwarded to any non-local addresses will be considered outbound.  If
possible, it's best to define the list of C<NextHops> to which you know
your outbound traffic is forwarded.

For most purposes, the default values for the rest of the C<CampusIO>
directives should suffice.  For advanced users that export from
multiple Ciscos to the same cflowd/FlowScan machine, it is also very
important to configure C<LocalNextHops>.

=item * Copy and Edit F<local_nets.boulder>

Copy the template to the F<bin> directory.  This file should be
referenced in F<CampusIO.cf> by the C<LocalSubnetFiles> directive.

The F<local_nets.boulder> file must contain a list of the networks or
subnets within your organization.  It is imperative that this file is
maintained accurately since flowscan will use this to determine whether
a given flow represents inbound traffic.

You should probably specify the networks/subnets in as terse a way as
possible.  That is, if you have two adjacent subnets that can be
coallesced into one specification, do so.  (This is differnet than the
similarly formatted F<our_subnets.boulder> file mentioned below.)

The format of an entry is:

   SUBNET=10.0.0.0/8
   [TAG=value]
   [...]

Technically, C<SUBNET> is the only tag required in each record.  You
may find it useful to add other tags such as C<DESCRIPTION> for
documentation purposes.  Entries are seperated by a line containing a
single C<=>.

FlowScan identifies outbound flows based on the list of nexthop
addresses that you'll set up below.

=item * Copy and Edit F<Napster_subnets.boulder> (I<if> referenced in F<CampusIO.cf>)

Note: if you do not wish to have C<CampusIO> attempt to identify
Napster traffic, be sure to comment out all Napster related option in
F<CampusIO.cf>.

Copy the template to the F<bin> directory from which you will be
running C<flowscan>.  The supplied content seems to work well as of
this writing (Mar 10, 2000).  No warranties.  Please let me know if you
have updates regarding Napster IP address usage, protocol, and/or port
usage.

The file F<Napster_subnets.boulder> should contain a list of the
networks/subnets in use by Napster, i.e. C<napster.com>.

As of this writing, more info on Napster can be found at:

   http://napster.cjb.net/
   http://opennap.sourceforge.net/napster.txt
   http://david.weekly.org/code/napster-proxy.php3

=item * Copy and Edit F<SubNetIO.cf> (I<if> you have selected it in your C<ReportClasses>)

Copy the template to the F<bin> directory from which you will be
running flowscan.  Adjust the values using the required and optional
configuration directives documented there-in.  For most purposes, the
default values should suffice.

=item * Copy and Edit F<our_subnets.boulder> (I<if> you use C<ReportClasses SubNetIO>)

Copy the template to the F<bin> directory.

This file is used by the C<SubNetIO> report class, and therefore is
only necessary if you have defined C<ReportClasses SubNetIO> rather
than C<ReportClasses CampusIO>.

The file F<our_subnets.boulder> should contain a list of the subnets
on which you'd like to gather I/O statistics.

You should format this file like the aforementioned
F<local_nets.boulder> file.  However, the C<SUBNET> tags and values in
this file should be listed exactly as you use them in your network: one
record for each subnet.  So, if you have two subnets, with different
purposes, they should have seperate entries even if they are
numerically adjacent.  This will enable you to report on each of those
user populations independently.  For instance:

   SUBNET=10.0.1.0/24
   DESCRIPTION=power user subnet
   =
   SUBNET=10.0.2.0/24
   DESCRIPTION=luser subnet

=back

=head2 Preserving "Old" Flow Files

If you'd like to have FlowScan save your flow files, make a
sub-directory named F<saved> in the directory where flowscan has been
configured to look for flow files.  This has been specified with the
C<FlowFileGlob> directive in F<flowscan.cf> and is usually the same
directory that is specified using the C<FLOWDIR> directive in your
F<cflowd.conf>.

If you do this, flowscan will move each flow file to that F<saved>
sub-directory after processing it.  (Otherwise it would simply remove
them.)  e.g.:

   $ mkdir $PREFIX/saved
   $ touch $PREFIX/saved/.gzip_lock

The F<.gzip_lock> file created by this command is used as a lock file
to ensure that only one cron job at a time.

Be sure to set up a crontab entry as is mentioned below in L<Final
Setup>.  I.e. don't complain to the author if you're saving flows and
your file-system fills up ;^).

=head1 Testing FlowScan

Once you have the patched cflowd running with the C<-s 300> option, and
it has written at least one time-stamped flow file (i.e. other than
F<flows.current>), try this:

  $ cd /dir/containing/your/time-stamped/raw/flow/files
  $ flowscan

The output should appear as something like this:

   Loading "bin/Napster_subnets.boulder" ...
   Loading "bin/local_nets.boulder" ...
   2000/03/20 17:01:04 working on file flows.20000320_16:57:22...
   2000/03/20 17:07:38 flowscan-1.013 CampusIO: Cflow::find took 394 wallclock secs (350.03 usr +  0.52 sys = 350.55 CPU) for 23610455 flow file bytes, flow hit ratio: 254413/429281
   2000/03/20 17:07:41 flowscan-1.013 CampusIO: report took  3 wallclock secs ( 0.44 usr +  0.04 sys =  0.48 CPU)
   sleep 300...

At this point, the RRD files have been created and updated as the
flow files are processed.  If not, you should use the diagnostic warning
and error messages or the perl debugger (C<perl -d flowscan>) to determine
what is wrong.

Look at the above output carefully.  It is imperative that the number
of seconds that C<Cflow::find took> not usually approach nor exceed
300.  If, as in the example above, your log messages indicate that it
took more than 300 seconds, FlowScan will not be able to keep up with
the flows being collected on this machine (if the given flow file is
representative).  If the total of usr + sys CPU seconds totals more
than 300 seconds, than this machine is not even capable of running
FlowScan fast enough, and you'll need to run it on a faster machine
(or tweak the code, rewrite in C, or mess with process priorities
using nice(1), etc.)

=head1 Performance Problems?

Here are some hints on getting the most out of your hardware if you
find that FlowScan is processing 300 seconds of flows in less an
averave of 300 CPU seconds or less, but not 300 seconds of real time;
i.e. the C<flowscan> process is not being scheduled to run often enough
because of context switching or because of its competing for CPU with
too many other processes.

On a 2 processor Intell PIII, to keep C<flowscan> from having to
compete with other processes for CPU, I have recently had good luck
with setting the C<flowscan> process' C<nice(1)> value to -20.

Furthermore, I applied this experimental patch to the Linux 2.2.18pre21
kernel:

   http://isunix.it.ilstu.edu/~thockin/pset/

This patch enables users to determine which processor or set of
processors a process may run on.  Once applied, you can reserve the 2nd
processor solely for use by C<flowscan>:

   root# mpadmin -r 1

Then launch C<flowscan> on processor number 1:

   root# /usr/bin/nice --20 /usr/bin/runon 1 /usr/bin/su - username -c '/usr/bin/nohup /var/local/flows/bin/flowscan -v' >> /var/local/flows/flowscan.log 2>&1 </dev/null &'

This configuration has yielded the best ratio of CPU to real seconds
that I have seen - nearly 1 to 1.

=head1 Final Setup

Once you feel that C<flowscan> is working correctly, you can set it
(and C<cflowd>) to start up at system boot time.  Sample C<rc> scripts
for Solaris and Linux are supplied in the F<rc> sub-directory of this
distribution.  You may have to edit these scripts depending on your
ps(1) flavor and where various commands have been installed on your
system.

Also, if you're saving your flow files, you should set up crontab
entries to handle the "old" flows.  I use one crontab entry to
C<gzip(1)> recently processed files, and another to delete the files
older than a given number of hours.  The "right" number of hours is a
function of your file-system size and the rate of flows being
exported/collected.  See the F<example/crontab> file.

=head1 Generating Graphs

=head2 Supplied Graphs

To generate graphs, try the F<graphs.mf> Makefile:

  $ cp graphs.mf $PREFIX/graphs/Makefile
  $ cd $PREFIX/graphs
  $ make

This should produce the "Campus I/O by IP Protocol" and "Well Known
Services" graphs in PNG files.  GIF files may be produced using the
C<filetype> option mentioned below.

If this command fails to produce those graphs, it is likely that some
of the requisite C<.rrd> files are missing, i.e. they have not yet been
created by FlowScan, such as F<http_dst.rrd>.  If this is the case, it
is probably because you skipped the configuration of F</etc/services>
in L<Configuring Your Host>.  Stop C<flowscan>, rename your
F<www_*.rrd> files to F<http_*.rrd>, modify F</etc/services>, and
restart C<flowscan>.

Alternatively, you may copy and customize the F<graphs.mf> Makefile to
remove references to the missing or misnamed C<.rrd> files for those
targets.  Also, you could produce your graphs using a graphing tool
such as RRGrapher mentioned below in L<Custom Graphs>.

Note that the F<graphs.mf> template Makefile has options to specify
such things as the range of time, graph height and width, and output
file type.  Usage:

   make -f graphs.mf [filetype=<png|gif>] [width=x] [height=y] [ioheight=y+n] [hours=h] [tag=_tagval] [events=public_events.txt] [organization='Foobar U - Springfield Campus']

as in:

   $ make -f graphs.mf filetype=gif height=400 hours=24 io_services_bits.gif

=head2 Adding Events to Graphs

There is a new graphing feature which allows you to specify events that
should be displayed in your graphs.  These events are simply a list of
points in time at which something of interest occurred.

For instance, one could create a plain text file in the F<graphs>
directory called F<events.txt> containing these lines:

   2001/02/10 1538 added support for events to FlowScan graphs
   2001/02/12 1601 allowed the events file to be named on make command line

Then to generate the graphs with those events included one might run:

   $ make -f graphs.mf events=events.txt

This feature was implemented using a new script called F<event2vrule>
that is supplied with FlowScan.  This script is meant to be used as a
"wrapper" for running rrdtool(1), similarly to how one might run
nohup(1).  E.g.:

   $ event2vrule -h 48 events.txt rrdtool graph -s -48h ...

That command will cause these C<VRULE> arguments to be passed to
rrdtool, at the end of the argument list:

   COMMENT:\n
   VRULE:981841080#ff0000:2001/02/10 1538 added support for events to FlowScan graphs
   COMMENT:\n
   VRULE:982015260#ff0000:2001/02/12 1601 allowed the events file to be named on make command line
   COMMENT:\n

=head2 Custom Graphs

Creation of other graphs will require the use of a tool such as
RRGrapher or knowledge of RRDTOOL.  RRGrapher, my Graph Construction
Set for RRDTOOL is available at:

   http://net.doit.wisc.edu/~plonka/RRGrapher/

For other custom graphs, if you use the supplied F<graphs.mf> Makefile,
you can use the examples there in to see how to build "Campus I/O by
Network" and "AS to AS" graphs.  The examples use UW-Madison network
numbers, names of with which we peer and such, so it will be
non-trivial for you to customize them, but at least there's an
example.

Currently, RRD files for the configured C<ASPairs> contain a C<:> in the
file name.  This is apparently a no-no with RRDTOOL since, although it
allows you create files with these names, it doesn't let you graphs
using them because of how the API uses C<:> to seperate arguments.

For the time being, if you want to graph AS information, you must
manually create symbolic links in your graphs sub-dir. i.e.

   $ cd graphs
   $ ln -s 0:42.rrd Us2Them.rrd
   $ ln -s 42:0.rrd Them2Us.rrd

A reminder for me to fix this is in the F<TODO> list.

=head2 Future Directions for Graphs

The current Makefile-based graphing, while coherent, is cumbersome at
best.  I find that the verbosity and complexity of adding new graph
targets to the Makefile makes my brain hurt.

Other RRDTOOL front-ends that produce graphs should be able to work
with FlowScan-generated C<.rrd> files, so there's hope.

=head1 Copyright and Disclaimer

=over 4

Note that this document is provided `as is'. The information in it is
not warranted to be correct.  Use it at your own risk.

   Copyright (c) 2000-2001 Dave Plonka <plonka@doit.wisc.edu>.
   All rights reserved.

This document may be reproduced and distributed in its entirety
(including this authorship, copyright, and permission notice), provided
that no charge is made for the document itself.

=back