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Network Security Alchemy

OpenFPC 0.1a – Installation and usage

with 2 comments

Firstly, I need to vent my anger at WordPress’s post formatting breakage. It is impossible for me to format this post using the Visual editor, and the HTML generated is so unbelievably ugly I can’t follow it.  So when the formatting of the text below doesn’t look correct blame wordpress not me.

I have uploaded a tarball of OpenFPC-0.1a to Googlecode, and as there isn’t any real documentation yet for OpenFPC I thought I would provide a few tips for people who want to try it out.

Firstly a word of warning: OpenFPC could be changing in the near future. I’m meeting up with ebf0 the author of FPCGui in June for a beer. Because duplicating effort is never a smart thing to do, and as both projects have similar goals it may make sense to pool some resources. Anyway, for the people who emailed me after my last post wanting to know how to get started with OpenFPC here are some tips.

The below is being performed on Ubuntu 10.04 LTS.

1) Check for requirements

OpenFPC depends on a few libraries and tools that need to be installed on the server you decide to dedicate for traffic collection. These include:

  • TCPdump
  • tshark (Part of the wireshark project)
  • mergecap (Part of the wireshark project)
  • daemonlogger (Version 1.2.1 or greater)
  • Perl
  • Perl Getopt::Long

On Ubuntu 10.04 LTS, all of these applications and librariers can be installed via apt without any real challenges. If they are not available in your Operating System’s package manager, you will have to go download and install them yourself.

lward@UbuntuDesktop:~$ sudo apt-get install tcpdump tshark daemonlogger

2) Install OpenFPC

Once those packages are installed, go download OpenFPC from here. This document was written for version 0.1a, but if there is a later release on the download list it’s best to use that. Once you have the tarball, extract it to somewhere in your home directory.

lward@UbuntuDesktop:~$ tar -zxvf openfpc-0.1a.tgz

If your dependencies are all satisfied, installation should be as simple as running the installer. And that should be it!

OpenFPC installs itself into /opt/openfpc, and looks for a configuration file in /openfpc.conf /etc/openfpc/openfpc.conf, /opt/openfpc/openfpc.conf (first config file found wins).
I suggest you start off by editing the file /opt/openfpc/openfpc.conf. Pay close attention to the FILE_SIZE and DISK_SPACE values. You will want to increase the FILE_SIZE value to over 10M for a production environment, it’s that default because of my testing on a VM. 1G or 2G would probably make more sense.
DISK_SPACE equates to a percentage of disk space to use on the capture partition. All other values should be pretty much obvious.
Once you’re happy with the values you have set, start up openfpc.

TIP: Because openfpc looks for a .conf file in your current working directory, be careful where you start/stop/extract pcap files from. I think I may change this behaviour in the future, but this is how it is for now.

lward@UbuntuDesktop:~$ /etc/init.d/openfpc status
[*] Reading configuration file /opt/openfpc/openfpc.conf
[!] No current buffers found in /var/tmp/openfpc – Have you started it yet?

lward@UbuntuDesktop:~$ sudo /etc/init.d/openfpc start
[sudo] password for lward:
[*] Reading configuration file /opt/openfpc/openfpc.conf
[-] Daemon mode set
[-] Interface set to eth0
[-] Logpath set to /var/tmp/openfpc
[-] Log filename set to “openfpc-pcap”
[-] Pidfile configured to “openfpc-dl”
[-] Pidpath configured to “/var/run”
[-] Rollover configured for 10 megabytes
[-] Rollover configured for 0 none
[-] Pruning behavior set to oldest IN DIRECTORY

DaemonLogger Version 1.2.1
By Martin Roesch
(C) Copyright 2006-2007 Sourcefire Inc., All rights reserved
Checking partition stats for log directory “/var/tmp/openfpc/.”
50% max disk utilization = 2467159 blocks free (out of 4934317)
 Blocksize = 4096
Rollsize = 2560 blocks
[-] It looks like daemonlogger has started successfully
[*] Traffic buffer (Daemonlogger) started on Tue May 25 17:16:28 BST 2010

Currently pcaps need to be requested locally using the tool, and only Snort-syslog, Snort alert_fast, Sourcefire3D, and Exim4 log entries are supported. If you would like support for another log format added that you use right now, send me samples via email (<myfirstname> Please only ask for log file formats that you are in a position to use and test, don’t just suggest nice-to-have.

So once you have a log entry you want to extract, run the command. I have one of my Snort instances writing events to syslog. I don’t make use of a nice Snort event UI like Snorby, Sguil, or Base on this device but when an event is triggered I want some more packet data.Here is an alert Ill use as an example (IP address’ are censored of course):

May 26 08:36:45 XXXXX snort: [1:2020:5] RPC mountd TCP unmount request [Classification: Attempted Information Leak] [Priority: 2]: {TCP} X.X.X.X:991 -> Y.Y.Y.Y:41208

To extract the session based on this log message, I will pass the -a “<LOG LINE>” arguments to

leon@rancid:~$ -a “May 26 08:36:45 rancid snort: [1:2020:5] RPC mountd TCP unmount request [Classification: Attempted Information Leak] [Priority: 2]: {TCP} ->”
*  – Part of the OpenFPC Project *
Leon Ward –
– Searching for traffic..
– Merging …
– Created /tmp/extracted-1274864016.pcap (1.1K Bytes)

I now have the complete session in the file /tmp/extracted-1274864016.pcap.
If you want to create your own wrapper scripts around ofpc-extract, you could use the -q (quiet) flag e.g.

leon@rancid:~$ FILENAME=$( -a “May 26 08:36:45 rancid snort: [1:2020:5] RPC mountd TCP unmount request [Classification: Attempted Information Leak] [Priority: 2]: {TCP} ->” -q)
*  – Part of the OpenFPC Project *
Leon Ward –
leon@rancid:~$ echo $FILENAME

Good luck with your sniffing!


Written by leonward

May 26, 2010 at 10:15 am

2 Responses

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  1. Added this to my site as a link… good work mate!

    Iain Greatrex

    May 26, 2010 at 8:01 pm

  2. Will start testing. good work.



    June 22, 2010 at 6:42 pm

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