Table of Contents
Part 3
Entries
Entry 9: April 6, 2012
Today I got Xfce4 running atop arch on my pogoplug. I forward the window manager through X11 via the network and interface with it on my client pc.
This is significant for a number of reasons:
- External GUI administration has an array of applicable uses.
- I can access web interfaces i.e. my router html config, all via a secure shell.
- I'm hoping to find a way to reduce latency of these applications over distant network connections.
Entry 10: April Day, 2012
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
- What action or concept of significance, as related to the course, did you experience on this date?
- Why was this significant?
- What concepts are you dealing with that may not make perfect sense?
- What challenges are you facing with respect to the course?
Remember that 4 is just the minimum number of entries. Feel free to have more.
Entry 11: April Day, 2012
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
- What action or concept of significance, as related to the course, did you experience on this date?
- Why was this significant?
- What concepts are you dealing with that may not make perfect sense?
- What challenges are you facing with respect to the course?
Remember that 4 is just the minimum number of entries. Feel free to have more.
Entry 12: April Day, 2012
This is a sample format for a dated entry. Please substitute the actual date for “Month Day, Year”, and duplicate the level 4 heading to make additional entries.
As an aid, feel free to use the following questions to help you generate content for your entries:
- What action or concept of significance, as related to the course, did you experience on this date?
- Why was this significant?
- What concepts are you dealing with that may not make perfect sense?
- What challenges are you facing with respect to the course?
Remember that 4 is just the minimum number of entries. Feel free to have more.
hpc0 Keywords
hpc0 Squid
Definition
Squid is an open source HTTP, HTTPS, and FTP proxy application that is flexible enough for Corporate, Education or personal use.
Demonstration
I'm going to setup my own proxy for HTTP and HTTPS so I may evade web restrictions whilst I'm out and about.
First I'm going to grab the Squid program for arch via the Pacman package manager:
[root@PogoLab ~]# pacman -S squid resolving dependencies... looking for inter-conflicts... Targets (8): cloog-0.17.0-1 gcc-4.6.3-1 isl-0.09-1 libmpc-0.9-2 libtool-2.4.2-4.1 mpfr-3.1.0.p7-1 ppl-0.12-1 squid-3.1.19-1.1 Total Download Size: 17.38 MiB Total Installed Size: 87.46 MiB Proceed with installation? [Y/n] y :: Retrieving packages from core... mpfr-3.1.0.p7-1-arm 319.8 KiB 343K/s 00:01 [##########################################################################] 100% libmpc-0.9-2-arm 53.4 KiB 502K/s 00:00 [##########################################################################] 100% isl-0.09-1-arm 377.5 KiB 488K/s 00:01 [##########################################################################] 100% cloog-0.17.0-1-arm 74.2 KiB 636K/s 00:00 [##########################################################################] 100% ppl-0.12-1-arm 1965.6 KiB 707K/s 00:03 [##########################################################################] 100% gcc-4.6.3-1-arm 13.5 MiB 1129K/s 00:12 [##########################################################################] 100% libtool-2.4.2-4.1-arm 268.5 KiB 650K/s 00:00 [##########################################################################] 100% :: Retrieving packages from extra... squid-3.1.19-1.1-arm 887.1 KiB 569K/s 00:02 [##########################################################################] 100% (8/8) checking package integrity [##########################################################################] 100% (8/8) loading package files [##########################################################################] 100% (8/8) checking for file conflicts [##########################################################################] 100% (1/8) installing mpfr [##########################################################################] 100% (2/8) installing libmpc [##########################################################################] 100% (3/8) installing isl [##########################################################################] 100% (4/8) installing cloog [##########################################################################] 100% (5/8) installing ppl [##########################################################################] 100% (6/8) installing gcc [##########################################################################] 100% (7/8) installing libtool [##########################################################################] 100% (8/8) installing squid [root@PogoLab ~]#
That's about it… make sure you've setup your router to forward port 3128 so squid my communicate externally. Set your proxy credentials on your client machine and you're off the races!
hpc0 squid.conf
For my proxy server I've settled with the following config file:
acl ip_acl src 192.168.1.0/24 http_access allow ip_acl http_access allow all cache_mgr asow123@gmail.com cache_mem 64 MB cache_dir diskd /var/log/squid/cache0 64 16 256 cache_effective_user andrew http_port 3128 transparent
This tells all trafic forwarded to the proxy on port 3128 to travel through its assigned port and return to the client. The cache is 64 megabytes (Enough for personal use.)
hpc0 superuser
A superuser is the root user. A system typically has a single root account and can allow other users superuser privileges. The concept of a superuser establishes a layer of security on your system; you wouldn't want to allow absolute log, program and file navigation access to every user.
An administrator or root user can add new sudo user in the /etc/sudoers file. Here is an example of a string adding sudo privileges to a user named joe:
joe ALL=(ALL) ALL
hpc0 sudo vs root
So want to be a super user? Think sudo's the same thing? Not quite. The difference between sudo and root execution is when a user executes a command using using sudo a log is kept of the commands used. This is not the case with root.
This log adds an additional layer of security.
hpc0 Unison
Unison is a great bidirectional directory synchronization application. I've setup a script to describe its functionality:
#!/bin/bash
_path="/home/andrew/Cloud"
_unison=/usr/local/Cellar/unison/2.40.63/bin/unison
_rserver="67.241.242.136"
for r in ${_rserver}
do
for p in ${_path}
do
${_unison} -batch /Users/asow123/Cloud "ssh://${r}/${p}"
done
done
Here is the script in action:
AirAndrew:/ andrew$ ./Unison.sh Contacting server... Connected [//AirAndrew//Users/asow123/Cloud -> //PogoLab//home/andrew/Cloud] Looking for changes Waiting for changes from server Reconciling changes props <-?-> props / local : dir props changed modified on 2012-05-02 at 21:26:20 size 2025059 rwxr-xr-x PogoLab : dir props changed modified on 2012-05-02 at 21:25:03 size 1946009 rwxr-xr-x new file <-?-> new file .DS_Store local : new file modified on 2012-05-02 at 21:23:17 size 6148 rw-r--r-- PogoLab : new file modified on 2012-04-30 at 18:06:57 size 6148 rw-r--r-- w file <-?-> new file Icon local : new file modified on 2012-04-30 at 17:54:31 size 79050 rw-rw-rw- icon MACS PogoLab : new file modified on 2012-04-30 at 9:46:17 size 0 rw-rw-rw- No updates to propagate AirAndrew:/ andrew$
hpc0 Generating ssh keys
Sometimes you just need indefinite access.
Definition
An ssh key will allow you to establish a secure shell with a trusted host if the server is compliant with clients generated key.
Demonstration
On the client side
ssh-keygen -t dsa
generates an ssh key for the remote server.
Add the key to this file ~/.ssh/authorized_keys
Then login! =D
hpc0 evn DISPLAY=:
Definition
Forwarding Applications is so cool!
Demonstration
You can forward applicaitons to other display environments like this:
[andrew@PogoLab ~]$ sudo env DISPLAY=:10 gparted ====================== libparted : 3.1 ====================== ^C[andrew@PogoLab ~]$
So… lets explain what just happened. On my MacBook I was ssh'd into @PogoLab and set gparted to open on my PowerBook that was ALSO connected to @PogoLab
The $DISPLAY number is what counts; :0 would be the local display and 10 was the SSH session connected to the PowerBook
hpc0 manual X11 forwarding
For when you're too good for just ssh -X
Demonstration
Let's say I want X apps to open on my macbook air when they are executed on @PogoLab. First I must add the remote ip of PogoLab to my X hosts on the macbook:
AirAndrew:~ andrew$ sudo xhost +192.168.1.101 Password: 192.168.1.101 being added to access control list AirAndrew:~ andrew$
Then on @PogoLab I must export my display to the macbook:
[andrew@PogoLab ~]$ export DISPLAY=192.168.1.147:0.0 [andrew@PogoLab ~]$
hpc0 Objective
hpc0 Objective
Play hard work hard
Definition
Through video games and other forms of digital entertainment, one can acquire a set of skills that enable that person to excel in the fundamentals of that subject.
Method
For instance, I didn't know how to forward ports via ssh before it was necessary when attempting to play MineCraft on a Lab46 VM-server.
Analysis
If you never make time for a little fun you may find your situation dull and stagnate.
Experiments
Experiment 7
Question
What is the question you'd like to pose for experimentation? State it here.
Resources
Collect information and resources (such as URLs of web resources), and comment on knowledge obtained that you think will provide useful background information to aid in performing the experiment.
Hypothesis
Based on what you've read with respect to your original posed question, what do you think will be the result of your experiment (ie an educated guess based on the facts known). This is done before actually performing the experiment.
State your rationale.
Experiment
How are you going to test your hypothesis? What is the structure of your experiment?
Data
Perform your experiment, and collect/document the results here.
Analysis
Based on the data collected:
- Was your hypothesis correct?
- Was your hypothesis not applicable?
- Is there more going on than you originally thought? (shortcomings in hypothesis)
- What shortcomings might there be in your experiment?
- What shortcomings might there be in your data?
Conclusions
What can you ascertain based on the experiment performed and data collected? Document your findings here; make a statement as to any discoveries you've made.
Experiment 8
Question
What is the question you'd like to pose for experimentation? State it here.
Resources
Collect information and resources (such as URLs of web resources), and comment on knowledge obtained that you think will provide useful background information to aid in performing the experiment.
Hypothesis
Based on what you've read with respect to your original posed question, what do you think will be the result of your experiment (ie an educated guess based on the facts known). This is done before actually performing the experiment.
State your rationale.
Experiment
How are you going to test your hypothesis? What is the structure of your experiment?
Data
Perform your experiment, and collect/document the results here.
Analysis
Based on the data collected:
- Was your hypothesis correct?
- Was your hypothesis not applicable?
- Is there more going on than you originally thought? (shortcomings in hypothesis)
- What shortcomings might there be in your experiment?
- What shortcomings might there be in your data?
Conclusions
What can you ascertain based on the experiment performed and data collected? Document your findings here; make a statement as to any discoveries you've made.
Retest 3
Perform the following steps:
State Experiment
Whose existing experiment are you going to retest? Provide the URL, note the author, and restate their question.
Resources
Evaluate their resources and commentary. Answer the following questions:
- Do you feel the given resources are adequate in providing sufficient background information?
- Are there additional resources you've found that you can add to the resources list?
- Does the original experimenter appear to have obtained a necessary fundamental understanding of the concepts leading up to their stated experiment?
- If you find a deviation in opinion, state why you think this might exist.
Hypothesis
State their experiment's hypothesis. Answer the following questions:
- Do you feel their hypothesis is adequate in capturing the essence of what they're trying to discover?
- What improvements could you make to their hypothesis, if any?
Experiment
Follow the steps given to recreate the original experiment. Answer the following questions:
- Are the instructions correct in successfully achieving the results?
- Is there room for improvement in the experiment instructions/description? What suggestions would you make?
- Would you make any alterations to the structure of the experiment to yield better results? What, and why?
Data
Publish the data you have gained from your performing of the experiment here.
Analysis
Answer the following:
- Does the data seem in-line with the published data from the original author?
- Can you explain any deviations?
- How about any sources of error?
- Is the stated hypothesis adequate?
Conclusions
Answer the following:
- What conclusions can you make based on performing the experiment?
- Do you feel the experiment was adequate in obtaining a further understanding of a concept?
- Does the original author appear to have gotten some value out of performing the experiment?
- Any suggestions or observations that could improve this particular process (in general, or specifically you, or specifically for the original author).