Mounting an SSH-accessible remote directory automatically is a nifty capability. Here's a nice description of how one can do that - specifically under Ubuntu but it will work the same just fine under most other Linux distributions:
Automatically mounting a remote directory in Ubuntu using autofs + sshfs
One thing not mentioned there - and something I keep forgetting about between the instances I need to recall it - is that the passwordless SSH login will fail unless the user directory on the SSH server is writable by the owner only! So, using the same terms as in the example above one should do the following:
1) Log into example.com as remoteusername
2) Execute the following command:
chmod g-w,o-w ~
Friday, December 30, 2011
Wednesday, December 14, 2011
The different flavors of 568
Yes, I admit this one was stupid. But cut me a little slack - last time I had to make network cables was many moons ago. And yes, I even got to make coax cables for 10 Mbit Ethernet. But no matter.
OK, so we got this spool of cable from a generic vendor with the cable labeled "ANSI/TIA-568-C.2". For some reason - looking at some pictures online, most likely - I decided that was to be wired according to the T568A layout. And wire them I did - a few cables, actually. Which worked fine in multiple jack with an exception of a Cisco Catalyst 2000 100 Mbit switch where they did not work at all.
Then I wired one cable to the T568B layout and it seems to work everywhere including that Catalyst 2900 switch. Given the T568C is said to have superseded T658B which in turn superseded T568A which is by now obsolete all of this seems to make sense. Hence it appears that the solution has been found.
Let me also take the time here to thank all those mailing list respondents whose guidance helped me figure this mess out. It always helps to have other minds to collect thoughts off of!
Reference:
TIA/EIA-568
Ethernet over twisted pair
How to wire Ethernet Cables
OK, so we got this spool of cable from a generic vendor with the cable labeled "ANSI/TIA-568-C.2". For some reason - looking at some pictures online, most likely - I decided that was to be wired according to the T568A layout. And wire them I did - a few cables, actually. Which worked fine in multiple jack with an exception of a Cisco Catalyst 2000 100 Mbit switch where they did not work at all.
Then I wired one cable to the T568B layout and it seems to work everywhere including that Catalyst 2900 switch. Given the T568C is said to have superseded T658B which in turn superseded T568A which is by now obsolete all of this seems to make sense. Hence it appears that the solution has been found.
Let me also take the time here to thank all those mailing list respondents whose guidance helped me figure this mess out. It always helps to have other minds to collect thoughts off of!
Reference:
TIA/EIA-568
Ethernet over twisted pair
How to wire Ethernet Cables
Monday, December 12, 2011
Saturday, November 19, 2011
Resume
Boris Epstein
Summary
Strong analytical abilities derived from both study and hands-on experience. Enjoy challenge and uncertainty. Seeking a position where I could contribute and grow, both professionally and personally.
15 years of full-time experience in the IT industry. That includes programming, systems administration (primarily various versions of UNIX and Linux) as well as network administration.
Participated in development, installation and maintenance of large-scale IT solutions in fields as diverse as telecommunications, financial, internet hosting, e-commerce, etc. Have experience developing standalone applications from scratch as well as working in a team. Diverse client interaction experience both domestically and internationally.
Operating Systems: UNIX, Linux, Mac OS X, MS Windows (XP, NT), MS DOS, Apollo Aegis, VMS
Programming Languages: C/C++, PERL, Ruby, JAVA, UNIX (C-Shell, Bourne, Korn), Tcl/Tk, PHP, Lisp/Scheme
Tools: Netbeans, Eclipse, Emacs, MS Office, OpenOffice, LibreOffice, FrameMaker, VI
Technologies: MySQL, PostgreSQL, SYBASE, Xen, VirtualBox, OpenVPN, Oracle RDBMS
Hardware: IBM-compatible PC, HP, SUN, Mac
Provided technical assistance to several online projects including Cooperative Research and New England JAVA Users Group.
In 2005, in the wake of Hurricane Katrina helped coordinate volunteer relief activities in the Gulf and personally participated in those activities.
Waltham, MA
Worked as a programmer involved in development and support of the ETMS air traffic management software for the FAA at the Volpe National Transportation Systems Center in Cambridge, MA. Specific area of concentration was the CDM component of the ETMS. The tasks included design and development of new functionality, as well as supporting legacy code. A large codebase together with the need for system reliability provide for a challenging task. The code was originally written in Pascal and later migrated to C.
The system was in essence a large transportation management system receiving and reflecting frequent (mostly once-a-minute) updates regarding the status of flights operating over the US airspace. Near realtime requirements were in place for processing and analyzing data which made for an exciting and challenging task.
Boston, MA
Performed multiple roles on a daily basis, including those of a senior system designer and developer, Windows NT and UNIX system administrator and web hosting support engineer. Key player in the technology planning and implementation area. As a sole expertise in a number of areas, including object-oriented design and development, networking, network security and systems management, advised other team members on various technology issues.
Main tasks included web site backend implementation for clients, in-house product design and implementation as well as day-to-day activities mentioned above. Most of the coding was done using object-oriented technology, with JAVA as a programming language of choice.
Provided critical insight which allowed to greatly improve stability and efficiency of the internal systems.
Clients included Davox Corporation (now part of Aspect Software), Pilates Store, Lobsters-Online, Inc. and others.
Thomson Financial
Medford, MA
Worked as a UNIX administrator in a large-scale web and dataserver hosting facility. Was responsible for maintenance and troubleshooting of multiple industrial-scale UNIX servers in SUN, HP and IBM platforms. Performed database maintenance of SYBASE and ORACLE databases as well as data recovery and general server troubleshooting.
Cambridge, MA
As part of the Y2K team worked on the remediation of custom SUN Solaris machines hosting clients' mission-critical WWW sites and applications. Complex upgrades and modifications had to be accomplished requiring an absolute minimum in customers' downtime. Tasks included upgrades of the OS, DB servers and various other third-party software. Custom scripting and coding was often required to facilitate the necessary transition.
Cambridge, MA
Originally hired as an outside contractor. Accepted a permanent staff position in a three months' time. Throughout my whole tenure was a critical part of a small and continually overtasked team.
Responsibilities included day-to-day maintenance and support of a network of UNIX hosts. Maintained code control systems. Designed and implemented a data backup/archival system for in-house use. Created web pages using HTML, PERL and JAVA. With the emphasis on publicly available software restructured the environment to optimize and economize the development and production process. Modified publicly available software for local needs using C, Tcl/Tk, PERL, JAVA, etc. Was also involved in equipment and software installation and support at client sites. Worked with medical applications and protocols including DICOM, ISG's VRS graphical application and AWARE wavelet compression. Wrote system installation and maintenance scripts. Modified and integrated various third party software packages. Worked with multimedia devices in medical data capture/processing systems. Set up and supported LANs and WANs.
Denver, CO - Cambridge, MA
Participated in database design of SYBASE databases.As part of a product team supported development effort in a heterogeneous UNIX environment. Oversaw the operation of a distributed development environment which included multiple geographically disjoint locations. Wrote a suite of PERL scripts that encompassed the local customizations to ClearCase as required by the project. Other responsibilities included release/code management using ClearCase code control system, SYBASE database administration, system design activities.
Cambridge, MA
Participated in the development of ATMS (Automated Traffic Management System), an air traffic management and control system for the FAA. Coding was done in Pascal against a proprietary database. The network consisted of a multitude of Aegis hosts on the Apollo platform. The development was done under DSEE as an integrated code control and management environment.
Born in St. Petersburg, Russia in 1969. Have lived in the US since 18 years of age. Attended Tver University (website in Russian) in Tver, Russia; Boston University and University of Massachusetts at Amherst graduating in 1992 with a Bachelor's Degree in Mathematics/Computer Science in 1992.
Hardware: IBM-compatible PC, HP, SUN, Mac
Timeline
May 2007 - present
May 2007 - present
National Resource for Imaging Mass Spectrometry
Cambridge, MA
Work as a jack of all trades though IT management is the focus of activities. Main responsibilities include maintaining the laboratories' computer systems, providing the data storage solution, maintaining the users' desktops and participating in the development of the lab's unique OpenMIMS analysis software module. Other tasks include general office management tasks such as placing and processing purchase orders, arranging various meetings and conferences, arranging shipments, etc.
Cambridge, MA
Work as a jack of all trades though IT management is the focus of activities. Main responsibilities include maintaining the laboratories' computer systems, providing the data storage solution, maintaining the users' desktops and participating in the development of the lab's unique OpenMIMS analysis software module. Other tasks include general office management tasks such as placing and processing purchase orders, arranging various meetings and conferences, arranging shipments, etc.
Beyond officially delineated responsibilities maintain my own privately-run VPN solution to provide connectivity to the lab's employees and collaborators outside the lab. Due to the distributed nature of the lab's activities this is a function critical to the lab's success.
April 2004 - May 2007
Travel. Educational activities. Occasional freelance projects.Provided technical assistance to several online projects including Cooperative Research and New England JAVA Users Group.
In 2005, in the wake of Hurricane Katrina helped coordinate volunteer relief activities in the Gulf and personally participated in those activities.
July 2001 - April 2004
ARCON CorporationWaltham, MA
Worked as a programmer involved in development and support of the ETMS air traffic management software for the FAA at the Volpe National Transportation Systems Center in Cambridge, MA. Specific area of concentration was the CDM component of the ETMS. The tasks included design and development of new functionality, as well as supporting legacy code. A large codebase together with the need for system reliability provide for a challenging task. The code was originally written in Pascal and later migrated to C.
The system was in essence a large transportation management system receiving and reflecting frequent (mostly once-a-minute) updates regarding the status of flights operating over the US airspace. Near realtime requirements were in place for processing and analyzing data which made for an exciting and challenging task.
December 1999 - April 2001
Boston Internet GroupBoston, MA
Performed multiple roles on a daily basis, including those of a senior system designer and developer, Windows NT and UNIX system administrator and web hosting support engineer. Key player in the technology planning and implementation area. As a sole expertise in a number of areas, including object-oriented design and development, networking, network security and systems management, advised other team members on various technology issues.
Main tasks included web site backend implementation for clients, in-house product design and implementation as well as day-to-day activities mentioned above. Most of the coding was done using object-oriented technology, with JAVA as a programming language of choice.
Provided critical insight which allowed to greatly improve stability and efficiency of the internal systems.
Clients included Davox Corporation (now part of Aspect Software), Pilates Store, Lobsters-Online, Inc. and others.
September 1999 - January 2000
Thomson Financial
Medford, MA
Worked as a UNIX administrator in a large-scale web and dataserver hosting facility. Was responsible for maintenance and troubleshooting of multiple industrial-scale UNIX servers in SUN, HP and IBM platforms. Performed database maintenance of SYBASE and ORACLE databases as well as data recovery and general server troubleshooting.
May 1999 - July 1999
GTE International (currently part of Level3 Communications)Cambridge, MA
As part of the Y2K team worked on the remediation of custom SUN Solaris machines hosting clients' mission-critical WWW sites and applications. Complex upgrades and modifications had to be accomplished requiring an absolute minimum in customers' downtime. Tasks included upgrades of the OS, DB servers and various other third-party software. Custom scripting and coding was often required to facilitate the necessary transition.
November 1995 - May 1999
WorldCare, Inc.Cambridge, MA
Originally hired as an outside contractor. Accepted a permanent staff position in a three months' time. Throughout my whole tenure was a critical part of a small and continually overtasked team.
Responsibilities included day-to-day maintenance and support of a network of UNIX hosts. Maintained code control systems. Designed and implemented a data backup/archival system for in-house use. Created web pages using HTML, PERL and JAVA. With the emphasis on publicly available software restructured the environment to optimize and economize the development and production process. Modified publicly available software for local needs using C, Tcl/Tk, PERL, JAVA, etc. Was also involved in equipment and software installation and support at client sites. Worked with medical applications and protocols including DICOM, ISG's VRS graphical application and AWARE wavelet compression. Wrote system installation and maintenance scripts. Modified and integrated various third party software packages. Worked with multimedia devices in medical data capture/processing systems. Set up and supported LANs and WANs.
July 1992 - November 1995
Kenan Systems Corporation (currently part of Alcatel-Lucent)Denver, CO - Cambridge, MA
Participated in database design of SYBASE databases.As part of a product team supported development effort in a heterogeneous UNIX environment. Oversaw the operation of a distributed development environment which included multiple geographically disjoint locations. Wrote a suite of PERL scripts that encompassed the local customizations to ClearCase as required by the project. Other responsibilities included release/code management using ClearCase code control system, SYBASE database administration, system design activities.
Summers of 1990 and 1991
Unisys CorporationCambridge, MA
Participated in the development of ATMS (Automated Traffic Management System), an air traffic management and control system for the FAA. Coding was done in Pascal against a proprietary database. The network consisted of a multitude of Aegis hosts on the Apollo platform. The development was done under DSEE as an integrated code control and management environment.
Personal
Born in St. Petersburg, Russia in 1969. Have lived in the US since 18 years of age. Attended Tver University (website in Russian) in Tver, Russia; Boston University and University of Massachusetts at Amherst graduating in 1992 with a Bachelor's Degree in Mathematics/Computer Science in 1992.
References
Available upon request. Monday, October 17, 2011
DamnVid
It came time to download some videos off YouTube to migrate them from one account to another... Dont' ask me why, that doesn't really matter. So, be that as it may - it is not as easy as it may seem. The FlashPlayer used to save them in your /tmp directory on Linux - but no more. The directory recommened at the link:
.mozilla/firefox/userprofile/cache
does not seem to contain anything resembling the video files one would expect either. However, then I followed a link specified at the above to get DamnVid and this seems to be working. The video ends up right under your ~/Videos directory hierarchy.
.mozilla/firefox/userprofile/cache
does not seem to contain anything resembling the video files one would expect either. However, then I followed a link specified at the above to get DamnVid and this seems to be working. The video ends up right under your ~/Videos directory hierarchy.
Thursday, June 30, 2011
NFS on Mac
It is really strange that NFS on Mac OS X is an absolute mess even though Mac OS X is UNIX-based and UNIX/Linux machines NFS mount to each other easily and conveniently.
I just moved my NFS server from SLES 10 to Cent OS 5.5 and guess what - Macs just want nothing to do with it. Oh, well, to be continued.
I just moved my NFS server from SLES 10 to Cent OS 5.5 and guess what - Macs just want nothing to do with it. Oh, well, to be continued.
Saturday, April 30, 2011
SFTP vs SSH
One might be inclined to think that they are one and the same, pretty much. Well, not quite.
We had this problem whereby the SSH worked fine but SFTP not at all. See the following desription:
SFTP seems to fail for NIS accounts under OpenSSH 5.x
Well, it ended up being a little different. What most of those NIS-based accounts had in common was a particular customisation in their BASH startup scripts (.bashrc, etc.) One .bashrc was removed the SFTP started working again.
Moral of the story? Whenever anything that could have to do with the login procedure goes wrong it might make sense to just maximally simplify the login procedure - such as remove all customisations, for instance - and try again.
We had this problem whereby the SSH worked fine but SFTP not at all. See the following desription:
SFTP seems to fail for NIS accounts under OpenSSH 5.x
Well, it ended up being a little different. What most of those NIS-based accounts had in common was a particular customisation in their BASH startup scripts (.bashrc, etc.) One .bashrc was removed the SFTP started working again.
Moral of the story? Whenever anything that could have to do with the login procedure goes wrong it might make sense to just maximally simplify the login procedure - such as remove all customisations, for instance - and try again.
Sunday, April 24, 2011
SANE: fixing an annoying network scan problem
On our network we've got a couple of Canon PIXMA network printer/scanner/FAX devices. Some versions of SANE apparently get confused trying to scan them with "network discovery" activated. The xsane application simply crashes.
After some searching on the web I have discovered what appears to be the fix. At least the fix has worked on a variety of Ubuntu 10.x machines, both 32-bit and 64-bit. I haven's saved the sources I used and can't locate them again so whoever was my inspiration on this one - please accept my apologies for failing to credit you.
So, be it as it may, here's the fix. Got to /etc/sane.d and edit the following file: epson2.conf . Comment out the following line:
net autodiscovery
You are done.
Final notice: after yet another round of updates on a 64-bit Ubuntu 10.10 machine I noticed that even this fix is not necessary it seems. But on slightly different installations this tip may still be of use.
After some searching on the web I have discovered what appears to be the fix. At least the fix has worked on a variety of Ubuntu 10.x machines, both 32-bit and 64-bit. I haven's saved the sources I used and can't locate them again so whoever was my inspiration on this one - please accept my apologies for failing to credit you.
So, be it as it may, here's the fix. Got to /etc/sane.d and edit the following file: epson2.conf . Comment out the following line:
net autodiscovery
You are done.
Final notice: after yet another round of updates on a 64-bit Ubuntu 10.10 machine I noticed that even this fix is not necessary it seems. But on slightly different installations this tip may still be of use.
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