Tag: proxy

Adobe Flash Player update: qui fait le malin tombe dans le ravin

Flash logoThis well-known French proverb is similar to: “pride comes before a fall”.

This evening I was told by the newly installed version of Firefox that my Flash player was outdated. Firefox provides a simple link to download that Flash Player. I save the installer (install_flashplayer10_mssd_aih.exe) in a directory where I save all my downloads before sorting them. I launch the installer. It moves itself to my system temporary directory and launches itself again. First I find it very rude from the installer to move itself anywhere on my disk. Then now, since 15 minutes it’s stuck at the step where it tries “retrieving install”.

Flash player stuck by proxy
Adobe Flash, if you want to play tricks, do it cleverly! Now your installation is stuck and cannot download the remaining part of the installer because it should use a proxy. This is a known issue, of course. And the simple and most obvious solution is that you can download the true, full Flash player installer here. Why not provide this link immediately?

R and the proxy server

R is a “a free software environment for statistical computing and graphics“. Being a desktop software, R is working out-of-the-box, even if you don’t have a network connection. However, if you want to install packages using a repository on the internet, you need a network connection (of course). If your computer happens to be behind a proxy server, you have to slightly modify your shortcut (in MS-Windows) to allow R to download packages. This can be done by modifying the “Target” field in the “Shortcut” tab of the shortcut properties (right-click on the shortcut to R, select tab “Shortcut”, edit field “Target”):

"C:\Program Files\R\R-2.12.2\bin\i386\Rgui.exe" http_proxy=http://proxyaddress:80 http_proxy_user=ask

Adapt the path to your R version, change the string “proxyaddress” by your proxy (see this previous post for a tip on this) and you’re done!

Because I never remember them, I’ll conclude this post with standard commands related to the installation of a packages:

Installing packages in R:
> install.packages("packageName", repos = "http://cran.ma.imperial.ac.uk/", dependencies = TRUE)

Notes:

  • You might get a window asking you for your firewall credentials and to choose a mirror server
  • CRAN repositories can be found here: http://cran.r-project.org/
  • This will download and install the package again, even if it is already installed

Updating packages in R:
> update.packages("deSolve") # for the deSolve package, for example

Know all packages installed in R on your computer:
> libraries()

Finally, here is a R reference card that can be useful too.

What is my proxy on Windows XP?

“In computer networks, a proxy server is a server (a computer system or an application) that acts as an intermediary for requests from clients seeking resources from other servers.” From Wikipedia. This can be useful for a company to force its employees to use a proxy (to filter where they surf, to cache the web content for speed issues, to keep machines on the network anonymous, etc.). This post will look at 3 ways to get the proxy definition for a Windows XP machine in order to use that information in another program. It may work in other Windows-type operating systems.

The first one is to use the command line tool proxycfg but this is different from the one that may be used by Internet Explorer, see here. On my corporate PC, there is no proxy defined this way. But there is one defined in Internet Explorer.

So, in Internet Explorer, to see the proxy connection, you go in the “Tools” menu -> “Internet Options” -> “Connections” tab. And then click on the “LAN settings” button. But this can be blocked by your PC administrator (it’s my case) so let’s look at the other options.

Another option is to use the Firefox (if your company allows you to use it): in the “Tools” menu -> “Options” -> “Advanced” tab -> “Network” tab, in the box named “Connection”, click on the “Settings” button. Then:

  • You have no luck if the settings are auto-detected.
  • If the option “No proxy” is chosen, your company doesn’t use a proxy.
  • If the option “Use system proxy settings” is chosen, you should have seen the proxy with the command line tool proxycfg above.
  • If the option “Manual proxy configuration” is chosen, you can directly read the parameters.
  • If the option “Automatix proxy configuration URL” is chosen, you can copy-paste the link given in the text field in the address bar to see how Firefox will determine which proxy to use. This page is just a bit of code that tells Firefox in which conditions it should use what proxy. You can find some details here or elsewhere on the web. You have to use the value just after the string “PROXY“. For instance, your proxy is “LOCATIONPROXY01” if your proxy string is “PROXY LOCATIONPROXY01“. If there are many proxy definitions, you have to try to understand the logic behind the .pac file if you want to be sure to find the correct one. Or you can try all of them (brute-force) and you’ll find the one that works.

I can’t read my blog

At least from my office. Sadly true 😉 since one of the rules of my company proxy server bans all URLs with the letters “blog” inside (no blogger.com, blogspot, … websites either). Fortunately, there are a lot of web-based feed aggregators (which are not — not yet? — banned). It also blocks all URLs with the “exe” string so we are not able to visit the Belgian Post website (it uses an URL containing “outletlocator.exe”) ; I didn’t find any bypass yet.

Banned blog by ISA server

Btw, with their message, we know they use Microsoft ISA Server as a proxy …