Tag Archives | CentraLUG

Notes from CentraLUG, 7-May-2007: Ben Scott on OpenWRT

Seven attendees got to enjoy the last CentraLUG meeting at the New Hampshire Technical Institute Library this academic year. The school will be closing on Friday, and summer hours will not accommodate CentraLUG. Stay tuned on an announcement of a summer location for June, July and August (September will have no meeting due to the Labor Day holiday).

Ben Scott was the featured presenter this evening, showing off the OpenWRT Linux distribution for embedded devices. The list of supported hardware [Updated the link — Ted] goes far beyond the initial LinkSys WRT-54G model to include products from dozens of other vendors. Many attendees brought their own routers for show-and-tell or backup. I had a v.1 WRT54G which I opened for folks to inspect. I also brought the compact (and alas, not yet flashable) WRT54GC. Bruce Dawson brought the WRTSL54GS, a Linux-flashable unit that includes a built-in USB connection. While Ben wrestled with the network and projector, we entertained ourselves well (and heckled Ben).

Ben had a well-prepared presentation, with schematics of the units, pictures of the circuit boards and some of hacks performed upon them, and a live demo of upgrading the unit from stock firmware to use the OpenWRT firmware and X-Wrt interface [3]. The OpenWRT includes a package manager and a large number of packages have been ported to the OpenWRT environment, ready for download. and installation.

Installation was uneventful – the Murphy gods must have been busy torturing the students in their finals week – and simple: select the “upload” option from the web interface and point to the OpenWrt image. Installation takes a short time and requires the router to be rebooted. Ben strongly advised clearing your browser cache, since the “same device” is going to be responding with different responses.

Ben gave us a quick tour of the OpenWRT interface and plunged right into installing X-Wrt. X-Wrt extends the interface and makes management far simpler, with some pretty incredible tools, like live SVG graphs showing actual network usage. Pretty impressive stuff.

Folks considering buying a new WRT54 will want to look for a “GL” unit where the “L” is Linux, the “GS” versions “Speedbooster” with more RAM or the “SL54GS” “Storage Link” that includes the USB connection also.

Bill also notes that it is possible to “brick” a unit. Ben says there are ways to de-brick them. Google ought to help, as would a post to GNHLUG.

Thanks to Ben for the great presentation, to Bill Sconce for providing the projector and notes, and to all for attending and participating.

Notes from CentraLUG, 2-April-2007: Bill Stearns on LVM

A great meeting last night. The Central New Hampshire Linux User Group met at the usual place and time: The New Hampshire Technical Institute‘s Library, Room 146, 7PM on the first Monday.

I did my usual rounds of announcements, Shawn O’Shea pointed out that besides for the discuss and announce mailing lists, you can also subscribe to the lists via RSS by using one of GNHLUG’s archival sites. Add one of these to your favorite RSS readers to see the GNHLUG announcements: mail-archive.com or gmane.org

Everyone got to introduce themselves and speak a little bit about what they’re up to. I passed around a couple lists of topics and speakers from the wiki to find out what the attendees want to see for future sessions.

Bill Stearns presented “LVM: Logical Volume Management.” He explained about the basic need to expand or re-allocate disk resources without making hard partition changes, in some cases without even shutting down. We started right in on an exercise: using the loopback device and some spare space in /var/tmp, we created three loopback block devices. We assigned them as PVs (Physical Volumes) and allocated two to a Volume Group. Then, space could be allocated out of the volume group to provide the space needed. Additional PVs could be added to the VG, additional space from the VG could be allocated to a mount. We had a good discussion about the choice of filesystems and the different processing required for ext3, reiser, xfs, jfs file systems – most of which can be resized when on-line. (Bill recommended the MythTV HOWTO for a good discussion of which file system to use.

We had a good side conversation at this point about the mount tables and the significance of several flags Bill had. An intesnse discussion of ‘noatime’ – useful for hierarchical file management, but generally of little use, and a lot of disk activity, power consumption, speed decrease, and for FlashROM devicers, perhaps lifetime shortening can be avoided by adding noatime to the mount tab. Bill also had war stories about the security implications of nodev and nosuid both of which are a good idea for insertable media unless you have a specific reason for needing them.

We finished up the LVM exercise by adding the third PV to the VG and then resizing the ext3 partition to include the space. Bill took questions from the audience: one lady had just installed LVM on the Linux partition on her mainframe (!) that weekend, and wanted to know more about LVM striping. Other questions on reliability, use with RAID. Bill had some pointers for adding additional storage: use of USB2 (not USB1!) external drives (Bill hasn’t been happy with Firewire storage on Linux) or using an external storage solution (he mentioned CoRAID which uses rackable ethernet-to-ATA raw drives; Bill had one sample to play with) and handled some questions further afield, like the file defragmenter Bill has on his site.

Yet another great LUG meeting. Thanks to Bill Stearns for the great presentation (and 3-ring-bound handouts) and providing the raffle door prizes. Thanks to Bill Sconce for providing the projector and doing the note-taking during the meeting. Thanks to the New Hampshire Technical Institute for providing the facilities.

Look forward to a great presentation on OpenWRT by Ben Scott at the May 7th meeting (where you can expect him to be heckled) and another great presentation on Drupal by Seth Cohn on June 4th. Hope to see you there.

PySIG, 22-March-2007: Project Night

An even dozen people showed up for the Python Special Interest Groups March meeting, held as usual at the Amoskeag Business Incubator in Manchester, NH.

Bill Sconce called us to order promptly at 7 PM and we proceeded through the printed agenda. It was duly noted the Ben Scott deserved heckling despite his absence. We ran through announcements of a couple of upcoming meetings, plugging the MythTV installfest beta and pointing out Jarod’s book. We mentioned meetings upcoming for the LUGs, including ZFS at DLSLUG, LVM at CentraLUG and the new Ruby group.

Kent’s Korner: Kent S. Johnson presented his month talk, this month on list comprehensions. Kent had a great handout, and has collected his past couple of handouts in one place. Starting with simple examples and building in complexity, Kent lead us through what can be an intimidating topic in a way most couple follow. Some great discussions, on-topic and off-, regarding assignment and Python idioms, always make this a fun part of the meeting.

There was some discussion of Python 3000 and its expected schedule. Bill Sconce had a video of Guido practicing his Py3K presentation in front of an audience at Google, which he went on to present at PyCon.

For the Gotcha of the month, Bill Freeman offered up an “Un-Gotcha:” a=b=4 works, but not for the reason you might think. Assignments of this style in C have a different underlying meaning, and perhaps in some circumstances, different side effects. A key to understanding the single = assignment in Python is to understand that it is a STATEMENT. There is no value associated with the statement and “chained” assignments in Python like the above are specially-coded as an exception case. This lead to yet another great discussion.

Ric Werme showed off the web pages that result from his Python software that collects and forwards weather data from his weather station. His current conditions page, http://home.comcast.net/~ewerme/wx/current.html has links to everything else. Ric bought the weather station in part to have an excuse to write more Python code, and his current code runs the gamut from implementing the weather station protocol through pyserial.py and the serial port to CGI scripts that take data requests, fetches the data from MySQL, creates gnuplot data files that create .gif files, and returns a HTML page to display the results. His description of the software is at http://werme.8m.net/wx/vantage_software.html .

Ric also demonstrated a Python cgi script for collecting data for a weather observers group that Todd Gross created while he was WHDH. It’s customizable, so people can create a form preloaded with their location that offer just the data they collect, and the submission code adds it to a MySQL database and recreates a web page of members reports over the previous day.

Shawn O’Shea showed off Python running in the Win32 and COM environments. Shawn does a lot of work administering and automating Windows configurations, and the COM set of interfaces can allow a lot of internal manipulation of the major applications, a big step up from the VBScripts supplied by Microsoft with some of the tools. Shawn demonstrated the canonical Hello, World with Microsoft Word, but then dug into a couple more concrete and practical examples with querying the Registry and spelunking in the IIS metabase.

Lots of interesting stuff coming up at future meetings: Martin Ledoux offered to show something on the work he’s done with amateur book-binding with pytut/pyref books. Kent has promised an update soon on his real-life experiences with Django. Ray Côté may be able to show off the new web site he used as an excuse to miss the meeting. And I’ll bet Bill will wheedle some more cookies from Janet.

Thanks to Bill Sconce for organizing, Alex Hewitt for getting the networking working, the Amoskeag Business Incubator for providing the great facilities, Janet for the awesome cookies, Kent for his great Korner, Bill Freeman for the csv module and those strange blinking white blocks, Ric Werme for demoing his weather projects, Shawn for the Win32-COM-Automation and everyone for attending and participating.

P.S. Anyone got python running on a WRT54G?

P.P.S. Tom Mosco mentioned to me that the Chicago Python group had a very long presentation on Django by the creators and also a Ruby on Rails presentation by its author. Videos can be found at here and here

CentraLUG, 2 April 2007: Bill Stearns on Logical Volume Management

The monthly meeting of CentraLUG, the Concord/Central New Hampshire chapter of the Greater New Hampshire Linux Users Group, occurs on the first Monday of each month on the New Hampshire Institute Campus starting at 7 PM.

This month, we’ll be meeting in our usual location, Room 146 of the Library/Learning Center/Bookstore, http://www.nhti.net/nhtimap.pdf , marked as “I” on that map. Directions and maps are available on the NHTI site at http://www.nhti.edu and on the GNHLUG site at http://wiki.gnhlug.org/twiki2/bin/view/Www/DirectionsToCentraLUG. The
main meeting starts at 7 PM, with Bill Stearns presenting LVM: Logical Volume Management. Open to the public. Free admission. Tell your friends.

Bill is an authority in the field of security, an instructor for the SANS Institute and an activist in several anti-spam efforts. Visit
http://www.stearns,org for a list of some of the interesting projects he’s been working on and packages he maintains. At April’s meeting, Bill will explain the infrastructure of LVM and how to work with it. LVM is a great technology that allows you to add disk space to running systems, manage the mapping of logical and physical volumes and manipulate disk usage. With the correct choice of hardware and file systems, much of the work can be done while the systems continue to run! Bill has some practical insights into how these systems work, and can talk about some of the subtleties of why you might choose LVM-atop-RAID vs. RAID-atop-LVM. Attendees are encouraged to bring laptops: using temporary space (no need to repartition), Bill will use some loopback tricks to let you create some devices and manipulate the LVM commands – a great hands-on experience!

More details at about this meeting and the group are available at http://www.centralug.org and http://www.gnhlug.org as I learn them!

In future meetings, we are looking forward to Ben Scott demoing OpenWRT (May) and Seth Cohn showing off Drupal (June) – dates and times not yet confirmed and in flux, so stay tuned. Hope to see you there!

CentraLUG notes from Andy Bair’s Digital Forensic File Carving presentation

Our thanks to Andy Bair for making the trip north from Massachusetts to present to the Central New Hampshire Linux User Group on March 5th, 2007, the first Monday of the month, at the New Hampshire Technical Institute’s Library. Andy announced that his work at MITRE was done and that he would be starting a job at Korelogic in the immediate future.

Andy worked with several friends at KoreLogic to take on the Digital Forensic Research Workshop (DFRWS) 2006 File Carving Challenge. They were supplied with a 50 megabyte “chunk” from a hard drive with the assignment to find as many files in that chunk as possible. The DFRWS’ motivation was to move the state of the art forward, and all participants were required to supply the source code of the applications they developed. Andy and his team won the challenge, beating out a number of other teams, notably Simson Garfinkel, who came in second. Andy demonstrated the procedures they worked out, talked about the algorithms they used, and showed the graphing of the results that made boundary detection and anomaly detection more easy to pick out. Andy and his team extended the UNIX magic technique to detect patterns in files, extending magic to XMagic which included regular expressions and more sophisticated rules to match files to the patterns. It was a very interesting presentation, presented well. Andy’s presentation, the source code and original data can be found at this link [Updated link – tr, 15-Feb-2010].

Thanks to Andy for the presentation, to Bill Sconce for supplying the projector, and to the New Hampshire Technical Institute for providing the facilities.

Upcoming presentations include:

  1. Bill Stearns demonstrating Logical Volume Management April 2nd,
  2. Seth Cohn presenting Drupal on May 7th, and
  3. Ben Scott presenting OpenWRT on June 4th.

We plan to meet at the usual location, but keep an eye out for a more detailed announcement as the date gets closer.

CentraLUG, 5 March 2007: Andy Bair, Digital Forensic File Carving

Originally, we had scheduled this presentation for November, but Andy Bair was called away at the last minute for a family emergency. He’ll be back in Concord New Hampshire to reprise his presentation, which has gotten rave reviews from several other local LUGs.

The monthly meeting of CentraLUG, the Concord/Central New Hampshire GNHLUG chapter, happens the first Monday of (most) month on the New Hampshire Institute Campus starting at 7 PM. Directions and maps are available on the NHTI site. This month, we’ll be meeting in the Library/Learning Center/Bookstore, room 146, marked as “I” on that map. The main meeting starts at 7 PM, and we finish by 9 PM. Open to the public. Tell your friends.

For this meeting, Andy Bair will present “Digital Forensic File Carving Techniques.” Data carving techniques are used during digital forensic investigations and existing file carving tools typically produce many false positives. This briefing describes new tools and techniques used by the winning team of the the 2006 File Carving Challenge held at the 6th Annual Digital Forensic Research Workshop (DFRWS). The current briefing is also located here.

Stay tuned for more information on future meetings: Bill Stearns will be presenting Logical Volume Management April 2nd and Seth Cohn will present Drupal on May 7th. More details on the group and directions to the meeting at http://www.centralug.org.

Notes from CentraLUG meeting, 5-Feb-2007: Matt Brodeur and GNUPrivacyGuard

We were lucky last night to have Matt Brodeur drive up from his day job at RedHat in Westford, MA to present a meeting on GPG, the open source implementation of OpenPGP, the Pretty Good Privacy algorithms and utilities. Matt had a slideshow in OpenOffice.org 2 Impress (available at http://www.nexttime.com/mbrodeur/GPG2007) and in PDF here.

Eleven attendees made it to the meeting. Matt briefly discussed the origins of PGP, and then dove right into the process and utilities of how Privacy Guard works. Matt also had brought some scripts he replayed to walk through the sequence of generating a key pair, signing another’s key, sharing keys to a keyserver. Matt walked us through the concepts behind the Web of Trust and the issues and processes of revoking keys. During the presentation and following, there were a fair number of questions and Matt dealt with them well.

Although we had hoped to have a keysigning as part of the meeting, we elected to postpone that portion to future meetings. As the group is fairly small, we agreed we can do individual signings as needed.

Future meetings: March 5th will feature Andy Bair talking about “Digital Forensics File Carving,” a popular topic he’s presented at several other groups. On April 2nd, William Stearns will do a presentation on Logical Volume Management. I saw Bill do an LVM presentation at DLSLUG back in 2005, and he had a great presentation. Looking forward to seeing both presentations!

CentraLUG, 5-Feb-2007: Matt Brodeur and GnuPG, OpenPGP, keysigning

The monthly meeting of CentraLUG, the Concord/Central NH GNHLUG chapter, happens the first Monday of most months on the New Hampshire Institute Campus starting at 7 PM. Next month’s meeting is on February 5th at 7 PM.

Directions and maps are available at http://www.centralug.org and on the NHTI site at http://www.nhti.edu/welcome/directions.htm. This month, we’ll be meeting at our usual location in the Library/Learning Center/Bookstore, room 146, marked as “I” on that map. The main meeting starts at 7 PM, and we finish by 9 PM. Open to the public. Free admission. Tell your friends.

At this month’s meeting, Matt Brodeur will present an introduction to e-mail and file security using Pretty Good Privacy (PGP). The talk will cover basic concepts of encryption and digital signatures. Examples and demos will use GNU Privacy Guard (GnuPG), a free (GPL) implementation of the OpenPGP standard available for most modern operating systems. Following the presentation, a PGP keysigning event will be held. Anyone interested in exchanging key signatures with other local PGP users can find details on our website,… as soon as we’ve set it up. Stay tuned.

Matt Brodeur is a Quality Assurance Engineer at Red Hat in Westford, MA and volunteer in local LUGs. He has previously presented OpenPGP talks at the Boston Linux & Unix User Group.

More details on the group and directions to the meeting can be found at http://www.centralug.org and at http://www.gnhlug.org.

CentraLUG: Asterisk and TrixBox

The monthly meeting of CentraLUG, the Concord/Central NH GNHLUG chapter, happens the first Monday of most months on the New Hampshire Institute Campus starting at 7 PM.

Directions and maps are available on the NHTI site at http://www.nhti.edu/welcome/directions.htm. This month, we’ll be meeting in the Library/Learning Center/Bookstore, room 146, marked as “I” on that map. The main meeting starts at 7 PM, and we finish by 9 PM. Open to the public. Tell your friends.

For December’s meeting, Tim Lind of Computerborough will present TrixBox, the CentOS-based distribution for running the Asterisk PBX software, formerly known as “Asterisk @ Home.” Trixbox (http://www.trixbox.org) is an open source PBX product that allows one to setup a full featured telephone system with extensions, personal voice mail, auto attendant and many, many more features within their home or office. Tim Lind of Computerborough has installed it many times and is using it on a daily basis within his company. Tim will show us around the configuration, and show some of the nifty things that can be done with it. Tim is a Red Hat Certified Engineer, A+ Certified Technician, Microsoft Certified Professional and is also Network+ certified. Tim has been using Linux since 1997 when he got bored with Windows and runs his business almost exclusively on open source products.”

January’s meeting falls on the first, so we’ll likely skip the month’s meeting. However, stay tuned for some exciting meetings coming up in 2007! Tentatively, we hope to have Andy Bair present Digital File Carving Forensics and Matt Brodeur talk about PGP and help us with a key-signing early in the year.

More details on the group and directions to the meeting at http://www.gnhlug.org.

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