Mon, 09 Mar 2009
How to use SSH as a replacement for telnet and ftp.
What is ssh and why should I use it?
Ssh or Secure SHell is a secure replacement for telnet. When using telnet, the characters you type on your keyboard, to send to the remote server, are sent in clear text. This means that anyone with access to the network can use a packet sniffer to find out exactly what you are typing. This includes your password. An attacker could then use your password to gain unauthorized access to the remote server. Afterward, your administrator would examine the server logs to determine the nature of the intrusion. These logs would reveal only that it was you! Ssh uses encryption to encrypt the text being transferred between you and the remote server. Anyone attempting to read this text will merely see a string of garbled characters. Telnet replacement is important in today's security minded networks. Ssh also has the ability to transfer files back and forth from you to your remote server. Scp lets you copy files to and from your remote server without having to actually login. Sftp looks and acts just like ftp. The final advantage of ssh is compression. Ssh compresses data before sending it to the remote host. This speeds up file transfers and decreases bandwidth usage.
Mon, 01 Sep 2008
Changing your password frequently
Organizations often set policies that require passwords to be changed frequently. I've seen that frequency as high as once every thirty days! This not only gives a false sense of security but it can actually be less secure.
Mon, 04 Feb 2008
A Review of OpenNMS
Neil H. Watson |
Abstract: This is a review of OpenNMS, version 1.3.9, an open source network monitoring system.
Sun, 21 Oct 2007
The Technocrat's Computer and Advice on Buying one
- Motherboard: Tyan S2466N-4M (Dual Socket A/462)
- CPUs: Athlon MP 2000 (Socket 462A)
- RAM: 1GB PC2100 Registered DDR
- Graphics Card: Nvidia GeForce 6200 with 128MB RAM
- Monitor 1: Viewsonic PF790 (19")
- Monitor 2: NEC (17")
- Modem: Alcatel Speed Touch Home
- Network Card 1: Integrated 3Com 3c905C
- Network Card 2: Intel Ethernet Express 100/10Mbit PCI
- Sound Card: Sound Blaster Live, Value
- Speakers: Altec Lansing ACS56 4.1
- Hard drive: Seagate ST3120026A, 120GB
- Hard drive: Seagate ST3250820A, 250GB
- DVD, CD burner: Plextor PX-712UF
- Keyboard: Microsoft Natural Keyboard
- Mouse: Microsoft Intellimouse Optical USB
- Full Tower: AOpen HX08: 5 5.5ext, 1 3.5ext, 7 3.5int, 3 fan, 7 card slots
- Printer: Lexmark Optra E310 (PostScript 2)
- USB 2.0 PCI card (Via chipset)
- OS: Debian Linux
My Advice
Now let's take a look at what I've chosen for my computer and I'll tell you my reasoning for each component. However, before we get to that, be aware that there are many web pages that will help you choose the right computer. I have learned much from these pages and so can you. I recommend Tom's Hardware and Sharky Extreme. They are both excellent resources and you should consult them for more exacting detail than I provide.
Sat, 02 Sep 2006
Tuning VXA-3 Performance in Linux
Abstract:
Performance tuning rsize and NFS
Abstract:
Mon, 17 Apr 2006
The other day I mentioned to a client that any lost files could be restored from a backup. The client stared at me blankly as if I had just spoken another language. I often lament that people that use computers should take the time to learn a thing or two. Not for my benefit but, for their own. Backups are a fine example. Would you live your life without car or house insurance? How about mortgage or life insurance? Most of us pay for at least one these yet almost no one has computer insurance. Take a minute to think about all of the data that is currently on your computer. My list includes:
This is by no means an exhaustive list. Now, imagine that all this data on your computer is suddenly gone. Forever. How much would you pay someone like me to get at least some of this data back? Believe me when I tell you that, in some cases, this could cost thousands of dollars. In other cases no amount of money will ever bring your data back. For some of you this will be a minor annoyance. For others, it could be a life altering event. Most people do not realize is that, a few minutes of work a week could have minimized this loss.
Mon, 13 Mar 2006
I have some files on my computer that I would rather not let people read. I have a file that stores authentication information to certain websites. I also have backups that I like to store on remote machines. I keep all of these files encrypted for privacy.
Sun, 20 Nov 2005
- Key Terminology
- Working with Email
- Calendar short cuts
- Notification Profiles
- Making Calls
- Desktop Software
- Synchronization
- Installing and updating software
- Backing up data
- Emergency reboots
Thu, 22 Sep 2005
Introduction
A version control system allows multiple people to work concurrently on many files without over writing each other's work. CVS is one of the most commonly used version control systems. Subversion was built as a replacement for CVS. Subversion has features similar to CVS. Additional features that the developers felt were lacking in CVS:
- Directories, renames, and file meta-data are versioned.
- Commits are truly atomic.
- Branching and tagging are cheap (constant time) operations
- Client/server protocol sends diffs in both directions
- Efficient handling of binary files
The following is a primer on the basics of Subversion. Note that the code
examples refer to the repository using the URL file:///. This
type of URL is used only if the user is working on the same system where the
repository resides. To access the repository remotely, the user can do so via
ssh. In that case, the URL would be svn+ssh://
Sat, 10 Sep 2005
The LiveCD Router is a running, statically configured router. It is powered by Gentoo Linux. Instructions orginated from this thread on Gentoo's high traffic support forums. Using the CD allows the user to convert virtually any PC, with two ethernet cards, into a router in minutes. This combined with the LiveCDs read only nature allows for fast disaster recovery.
The CDROM is based in Gentoo's install CD. Officially it is called the LiveCD. The LiveCD is simple and console only. Its primary function is to install Gentoo to a computer but, can also function as a rescue CD. The CD is open source. This allows anyone to create their own copies of the LiveCD to serve other purposes, like routers. Other types of LiveCDs include gaming CDs and Flashlinux which runs on a 256MB USB key. A full GUI LiveCD, similar to Knoppix, is scheduled for release 2005.
Sat, 12 Mar 2005
"Where do you want to go today?"
Notice that Microsoft never asked you how fast you wanted to go during your trip? There is an endless debate over the performance of Windows. Generally, it is felt that it could be better. Here are a few things you should and should not do to keep your Windows PC performing:- Do keep a minimum of programs installed on your machine. Many users install programs on their PCs, use them once and leave them. Everytime you install a program on your computer you enlarge the Windows registry. The registry is the heart of Windows. It is a collection of about 4 different files. The larger these files get the slower your PC will run.
Uninstall the programs you are no longer using and you'll save disk space and keep performance up. - Do Reboot once a week. In theory, when you close down an application Windows will free the memory it was using making it available for other applications. Windows does not do this well. In fact some of the memory is not made available again after an application is closed. As a result, the longer you run your computer the less memory will be available for you applications.
- Do regularly defragment your on hard drive. Windows stores files in the first free space it can find your hard dirve. If that space is not large enough for the file, it stores a portion of the file and looks for the next space and stores the next portion there. This continues until all the file is stored. The result is that many of your files are stored in "fragments" across the hard disk. This is called "disk fragmentation" and it can seriously slow down your machine as Windows looks for files that are stored across the hard drive instead of at a single location. If you defragment your hard drive, Windows reconstructs the files into single blocks. This will speed up the disk performance of your machine.
To do this open the My Computer icon and right click on your disk drive icon. Now select properties and touch the Tools tab. Click the defrag button and it opens the defragmentation tool. Run this once every other week. It is a slow process so you may want to run it over lunch or overnight. - Do not have to many applications running. Every application takes up valuable RAM. Windows takes well over half your RAM just to start. Realplayer, chat programs, news and stock tickers, all take up your RAM. If you are not using them every few minutes turn them off. Your machine will run faster for it.
- Do not let your hard drive run out of space. Generally 15%-20% of your hard drive should be empty. Windows is constantly creating and deleting temporary files. If there is no space left to create these files Windows will stop working. This is a permanent crash and cannot be recovered without reinstalling Windows.
Fri, 28 Jan 2005
Want your own domain?
Learn from my 6 weeks of stress. Make it easy on yourself!
There are some useful references for this on the net. However, they are mainly geared towards the USA. Up here in Canada things are a little different. First, our choices in broadband ISP are much less than our southern neighbours. I've tried to make the points generally OS non specific. I use Linux so I can't speak for other OSs.
Sun, 02 Jan 2005
An Open Letter from one Administrator to Users Everywhere
Help Me Help You
I have been a network administrator for many years. It has been said that administration is hours of boredom interrupted by moments of sheer panic. Through the highs and lows of this existence there is one constant: answering user requests.
Accounting for a large part of my day, users requests can be both rewarding and frustrating. Users, I know your computer can infuriate you at times. I feel for you. I want to help you. I want you to learn how the computer can make your day to day work easier. Unfortunately, I cannot help you unless you are willing to help yourselves.