slow ssh login sequence

Recently I noticed that my ssh login sequences took a long time (give or take 5 seconds). After disabling the “Automatic service discovery”, it returned to it’s normal (and fast) state.

Go to “System” -> “Network” -> “General”, and deselect the “Automatic service discovery”.

Linux distribution for embedded devices

Wireless routers
You can flash various wifi access points with openwrt. From then on you can even customize the device with packages you want. Like for instance a small http daemon or such.

Storage Devices
Here we have the Linksys NSLU2 wich has it’s own “homebrew” firmware available at nslu2-linux.org. With this you can turn your small low cost storage device into a small linuxcomputer.

These are the ones I know about… If you know other, feel free to post them in the comments section.

The wordpress plugins you should have!

Akismet
THE spam filter for your comments section. The stats currently shown in my own dashboard: “Akismet has protected your site from 79 spam comments.” And the numbers increase on a daily basis!

aLinks
Very useful for deeplinking in your own blog. Like for example the “solaris” link you can see here…

Google Sitemaps
No site should go without a sitemap… Treat your site with the SEO it deserves!!!

Gregarious
Described as “The ultimate social bookmarking plugin.”, and it does just that.

Open Web Analytics
Know your visitors, and why they are YOUR visitors.

Some other useful ones:
wp-syntax
wp-contactform

Solaris: Swap Space and the TMPFS File System

Description
The TMPFS file system is activated automatically in the Solaris environment by an entry in the /etc/vfstab file. The TMPFS file system stores files and their associated information in memory (in the /tmp directory) rather than on disk, which speeds access to those files. This results in a major performance enhancement for applications such as compilers and DBMS products that use /tmp heavily.

The TMPFS file system allocates space in the /tmp directory from the system’s swap resources. This means that as you use up space in /tmp, you are also using up swap space. So if your applications use /tmp heavily and you do not monitor swap space usage, your system could run out of swap space.

Swap-Related Error Messages
These messages indicate that an application was trying to get more anonymous memory and there was no swap space left to back it.

application is out of memory

malloc error O

messages.1:Sep 21 20:52:11 mars genunix: [ID 470503 kern.warning]
WARNING: Sorry, no swap space to grow stack for pid 100295 (myprog)

TMPFS-Related Error Messages
directory: File system full, swap space limit exceeded

This message is displayed if a page could not be allocated when writing a file. This can occur when TMPFS tries to write more than it is allowed or if currently executed programs are using a lot of memory.
directory: File system full, memory allocation failed

This message means TMPFS ran out of physical memory while attempting to create a new file or directory.

See TMPFS(7FS) for information on recovering from the TMPFS-related error messages.

ssh connection sharing

Ever wanted to share ssh connections? You logged in the first time, but when doing the second you’re wondering: “Why didn’t it remember my credentials?”

You can share connections thru a simple config tweak…

Edit your .ssh/config:

Host *
ControlMaster auto
ControlPath ~/.ssh/control_%r@%h:%p

There is a downside however: if the first connection is closed, then all connections are closed…

Related links: here & here

ssh tunnel thru http proxy

install corkscrew : sudo apt-get install corkscrew (under ubuntu/debian)

edit your ~/.ssh/config file:

Host *
ProxyCommand corkscrew proxy.server.com 3128 %h %p

Where 3128 is the default port of a squid proxy server…

For more info on how to adjust your ssh config file do:

man ssh_config

If you’re getting one of the errors below, then you’ve made an error in the config file:

  • ssh_exchange_identification: Connection closed by remote host
  • ssh: connection to host example.net port 22: Connection timed out

Other pages containing related information: here & here

HOWTO : Ubuntu – pdf printing

– Install the “cups-pdf” package
– (xubuntu) go to your “menu” -> “system” -> “printing” -> “new printer”
– select “PRD Printer (Virtual Printer)” under “Use a detected printer”, then press forward
– select “generic” -> “PostScript (Color)” -> “Standard”
– name it, and press apply
– The printer is ready to be used
– notice that the pdf documents will be printed to the “PDF” directory within your home directory