A Few Reasons to Love Ubuntu [Guest Post]

Date: November 4, 2011. Categories: reviews. 0 Comments

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The term “Ubuntu” hails from South Africa and is defined as “humanity or kindness”… The meaning of this word is the whole philosophy behind the operating system named after it — Ubuntu.

The company of Ubuntu believes that software should be available free of charge, that tools should be usable by people in their native language and despite any disabilities, and that users have the accessibility to customize and make changes to their software as they please. Well if that didn’t sound awesome enough, here are a few more reasons to love Ubuntu:

#1: Surf the web quickly and safely. One of the great things Ubuntu has going for it is its equipment for providing you everything you need to browse the web quickly and in a secured fashion. Ubuntu comes with Firefox as a standard browser, but you are also given the option of alternatives like Google Chrome found in the Ubuntu Software Centre. And with the latest in anti-phishing technology, automatic security updates, and Linux’ native defense against viruses… Ubuntu makes sure that all of your information is private and yours alone.

#2: Be professional with office applications. Ubuntu is built with LibreOffice which has the tools necessary to create the most professional level of documents, spreadsheets and presentations. Not only can you use LibreOffice, but Ubuntu is compatible with Microsoft Office so you are able to open and work on projects in Word, Excel and PowerPoint.

#3: Social network and email, galore. Ubuntu comes chalk-full of applications that allow quick and easy communication from the main panel. Here are a few that are sure to keep you connected on levels of both business and play:
Empathy: an app that helps you integrate your chat accounts into one.

  • Thunderbird: gives you access to your emails, address book and calendar—perfect for the business-minded individual.
  • Gwibber: a tool that keeps you up to date with people in your social networks…you can see all of your microblogging feeds in one place.
  • Skype: a video chat app that allows you to video-call your friends, family and colleagues wherever you are.

#4: Get music and go mobile. No matter what your musical tastes, Ubuntu gives you what you need to play, create and edit MP3s, stream music to your PC or phone, buy music or connect to programs like Spotify and Last.fm. Use Ubuntu One to do a number of things like:

  • Sync your music and stream your whole collection straight to your iPhone or Android.
  • Built into the Rythmbox Music Player, the Ubuntu One Music Store offers instant access to millions of songs to purchase. This falls perfectly into the Ubuntu Software Centre’s ability to enable you to purchase commercial software right from the desktop.
  • You get 5GB free storage for your files, contacts and notes — with the option of adding more space if you need it.

#5: Enjoy your pics and video. Ubuntu provides you with tons of free apps to help you manage, edit and share your pictures and videos. Another benefit? The operating system supports any device you use to capture your life so that you won’t need any extra drivers. Try this great app: Shotwell, it helps you import, organize and edit your pictures so that they are ready to share with the world.

#6: Take advantage of the Ubuntu Software Centre. The massive Ubuntu Software Centre brings you access to thousands of free, open-source applications. You will be able to easily install the software and customize your desktop however you choose. Each app comes with reviews and ratings to help you decide which ones you want…and you also have the ability to create and publish your own! Pick your apps from the following categories: Accessories, Games, Science & Engineering, Universal, Access, Graphics, Sound & Video, Education, Internet, Fonts, Office.

Sabrina Jackson is a guest post author who shares with us her input on the operating system, Ubuntu. Sabrina is also an author for Best Free Dating Sites where she covers topics centered on dating and relationships.

Phone call as Nagios notification

Date: September 13, 2011. Categories: applications, howtos and linux. 0 Comments

Some time ago I found it pretty useful to configure Nagios monitoring system to send me a phone call in case of some critical problem. If some mission critical application goes down at night most probably you’ll miss an e-mail or sms notifying about that but won’t miss a telephone call to your cell phone. Honestly a telephone call is much more notorious rather than IM message notification or, again, e-mail/sms. You’re welcome to see below how to configure your Nagios for that.

First of all you need to have account at some SIP voip service provider like www.voiptalk.org or similar (Skype is not an option so far). Once registered you will get SIP username/password and SIP gateway’s IP address which will be used to make outgoing calls by Nagios.

1. Download and install pjsua console caller from pjsip.

cd /usr/src/
wget http://www.pjsip.org/release/1.10/pjproject-1.10.tar.bz2
tar -xvjf pjproject-1.10.tar.bz2
cd /usr/src/pjproject-1.10
./configure --disable-sound
make
sudo cp pjsip-apps/bin/pjsua-i686-pc-linux-gnu /usr/bin/pjsua

2. Configure pjsua.

Create /etc/pjsuarc configuration file with the following contents (depends on details provided by SIP provider):

--null-audio
--registrar sip::5060
--realm=*
--id sip:<username>@<SIP gateway IP>:5060
--username <username>
--password <password>

From that point you can try calling yourself by command:

/usr/bin/pjsua --config-file=/etc/pjsuarc sip:<your phone number>@<SIP gateway IP>

3. Configure Nagios to notify you by sending you a telephone call:

Add the following block to Nagios’ commands.cfg:

define command{
        command_name  notify-host-by-sip
        command_line  (sleep 30 && echo q) | /usr/bin/pjsua --config-file=/etc/pjsuarc sip:$CONTACTEMAIL$
}

Add below contact to Nagios’ contact.cfg:

define contact{
        contact_name  user_sip
        alias  useralias
        service_notification_period  24x7
        host_notification_period  24x7
        service_notification_options  c
        host_notification_options  d
        service_notification_commands  notify-service-by-sip
        host_notification_commands  notify-host-by-sip
        email  <your phone number>@<SIP gateway IP>
}

That’s it, from this point Nagios will call you in case of critical problem and won’t bother you with warnings.

Linus Torvalds — The Facts You Didn’t Know

Date: July 15, 2011. Categories: linux and reviews. 0 Comments

Linus TorvaldsSome of you may well be younger than Linux, some of you may have grown up with the OS, and some of you, more ancient ones, may well remember thinking that this stuff is going to ‘blow the bloody doors off’ as Michael Caine put it when you first encountered it. But how about Linus Torvald, the man who wrote the first kernel? Here we’re going to give you an insight into his life and personality.

He is Finnish but actually grew up speaking Swedish. This is because Linus is one of the “finlandssvensk” or “finlandssvenskar” community in Finland. These were Swedes who moved to Finland many hundreds of years ago when the country was part of the Swedish Empire and continue to speak Swedish.

It was on August 25th 1991 that Linus announced to the Usenet newsgroup “comp.os.minix.” that he was making a free OS, although he thought it wouldn’t be big or professional like Gnu. Well, who would have thought that Linux would turn the computing world on its head?

He hates phones, which he believes distracts him from more important things in life. This doesn’t mean he doesn’t own a phone, he just uses it for the GPS function when he’s driving.

Linus Torvald rarely gets to code any more. This is not because he’s spending all his time looking at his bill on www.o2.co.uk or crafting amazing images on photoshop, no, he’s replying to a huge email in-box and the few bits of code he does write are usually pasted in emails to questions explaining what to avoid.

I don’t know how much tea or coffee you drink, but Linus reckons he is a coffee addict and calculates that he and his wife have drunk an average of 4.7 double shots per day between 2002 and 2010 and that’s not including take-out coffees.

Despite this caffeine intake, he still manages to get a fairly serious nine hours sleep a night (he goes to bed at 10 and gets up at 7).

Perhaps this is because he likes drinking Guinness, that Irish stout from Dublin that contains a serious amount of iron and used to be taken as a health tonic in the British Isles before modern fads changed peoples’ opinions.

Prior to having laser surgery, Linus used to wear spectacles.

He is married and lives in Portland, Oregon with his wife Tove and their three daughters.

[ This is sponsored blog post. Feel free to contact me via artiomix at gmail dot com for more details about availability and prices for sponsored posts. ]

The Implementing Cisco IP Routing (CCNP Route 642-902). Materials for efficient preparation to the exam.

Date: July 7, 2011. Categories: cisco and docs. 0 Comments

cisco logoA few days ago I have successfully passed 642-902 exam (CCNP ROUTE v6) and would like to share the list of materials I have been using to prepare to that exam. To get prepared I was using official Cisco Press training resourses, lab simulations and cheat sheets (before actually to go an take the exam). In this post I’d like to share this staff with you.

A few words about CCNP ROUTE 642-902 exam. This is the first one of three qualifying exams for CCNP, CCIP and CCDP. If you plan to become one of those certifications you must take 642-902 (the possibility to take the composite CCNP exam is also opened). Cisco ROUTE exam contains detailed information regarding implementing of EIGRP, BGP, OSPF dynamic routing protocols, redistribution between different protocols, filtering, summarization/aggregation and a lot of related stuff. You can read more at Cisco Learning Center.

Main Preparation Materials

Lab Simulations

I’ve been using the only available emulation software of this kind: dynamips. There are a lot of information available about it around the web. Meantime it is worth to say that Packet Tracer’s functionality is far not enough to complete labs coming with CCNP ROUTE so using of dynamips is mandatory. It is clear that every lab include more than three routers in it so you should be able to interconnect devices between each other using different kinds of connection e.g. Serial or FastEthernet. I used GNS3 for this purpose and it did its job perfectly.

Cisco CCNP ROUTE Cheet Sheets

Before actually to take an exam it makes sense to sum everything up in your mind so you should us cheat sheets for this purpose. I’ve been using Cisco cheat sheets which were prepared by Jeremy from www.packetlife.com, here are the direct links to them:

Good luck!

Cisco Load Balancing with Failover setup example

Date: February 27, 2011. Categories: cisco and howtos. 0 Comments

cisco logoThere is Cisco router of 7200 series with 4 FastEthernet interfaces (FE) and 2 serial ports. It should act as load balancer and failover for LAN connected to it via one FE 1/0 interface while two identical Internet connections are going to FE 0/0 and FE 0/1 (let’s name these connections as ISP_1 and ISP_2).

No dynamic routing protocols are used by ISPs but only static routing. The primary task is to ensure quick failover between two Internet connections so LAN users are automatically switched to ISP_2 if ISP_1 fails and vice versa. When both ISP_1 and ISP_2 are online the traffic of LAN users should be shared between two links to double available bandwidth on uplink (Tx) and downlink (Rx), in other words the router should be configured for load balancing between the links. You can see a network diagram below:

Load balancing setup description

There are two basic options available: per-destination or per-packet load balancing. Since ISP_1 and ISP_2 connections have almost the same link characteristics including delay, jitter and bandwidth, it is reasonable idea to pick per-packet option. In comparison to per-destination load balancing approach per-packet uses more router’s hardware resources but makes it possible to share traffic between connections more evenly. For better forwarding performance the router will be configured for Cisco Express Forwarding or simply CEF per-packet load balancing.

Failover description

Every 30 seconds the router will ping two IP addresses through ISP_1 and two other IP addresses via ISP_2. If both IPs via ISP_1 becomes unreachable (we assume that ISP_1 connection fails in this case) the router will delete ISP_1’s route from its routing table so ISP_2 becomes the only Internet connection for LAN users. Meantime the router still continues pinging two ISP_1’s IP addresses and once they become reachable back ISP_1 is added to ISP_2 as an active Internet connection link. Such failover scenario works in absolutely the same way for ISP_2. Usually this is reasonable idea to ping IP addresses of each provider’s DNS servers when monitoring availability of each ISP.

Miscellaneous details

Notice that CEF per-packet load balancing requires IOS version of 12.0+ while failover setup described above needs 12.4+ IOS version so you have to make sure your Cisco router runs at least 12.4 version of operating system. E.g. c7200-ik9o3s-mz.124-12c.bin would be ok.

Cisco router’s configuration with comments

! This line enables Cisco Express Forwarding (CEF)
ip cef
!
ip sla monitor 1
 type echo protocol ipIcmpEcho 10.0.0.100 source-interface FastEthernet0/0
 ! IP address 10.0.0.100 is primary DNS of ISP_1
 timeout 1000
 threshold 250
 frequency 30
ip sla monitor schedule 1 life forever start-time now
ip sla monitor 2
 type echo protocol ipIcmpEcho 10.0.0.101 source-interface FastEthernet0/0
 ! IP address 10.0.0.101 is secondary DNS of ISP_1
 timeout 1000
 threshold 250
 frequency 30
ip sla monitor schedule 2 life forever start-time now
!
!
ip sla monitor 3
 type echo protocol ipIcmpEcho 20.0.0.100 source-interface FastEthernet0/1
 ! IP address 20.0.0.100 is primary DNS of ISP_2
 timeout 1000
 threshold 250
 frequency 30
ip sla monitor schedule 3 life forever start-time now
ip sla monitor 4
 type echo protocol ipIcmpEcho 20.0.0.101 source-interface FastEthernet0/1
 ! IP address 20.0.0.101 is primary DNS of ISP_2
 timeout 1000
 threshold 250
 frequency 30
ip sla monitor schedule 4 life forever start-time now
!
!
track 1 rtr 1 reachability
track 2 rtr 2 reachability
track 3 rtr 3 reachability
track 4 rtr 4 reachability
!
! Tracker for ISP_1
track 10 list boolean or
 object 1
 object 2
!
! Tracker for ISP_2
track 20 list boolean or
 object 3
 object 4
!
! Interface connected to ISP_1
interface FastEthernet0/0
 ip address 10.0.0.2 255.255.255.0
 ip load-sharing per-packet
 duplex auto
 speed auto
!
! Interface connected to ISP_2
interface FastEthernet0/1
 ip address 20.0.0.2 255.255.255.0
 ip load-sharing per-packet
 duplex auto
 speed auto
!
! Interface connected to LAN
interface FastEthernet1/0
 ip address 192.168.100.2 255.255.255.0
 ip load-sharing per-packet
 duplex auto
 speed auto
!
! Two equal cost static routes to ISP_1 and ISP_2
ip route 0.0.0.0 0.0.0.0 10.0.0.1 track 10
ip route 0.0.0.0 0.0.0.0 20.0.0.1 track 20
!

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 My name is Artem N. (artiomix AT gmail DOT com) and I'm Linux/Unix, Cisco systems engineer. The main idea of Linux Screw is to share relevant knowledge, skills and observations over The Web. Here you can find a lot of information related to different Linux distributions, FreeBSD, IOS as well as a other Open Source around staff. Read more ››