Posts Tagged ‘custom’

Happy New 2012 Year, few Bulgarian New Year traditions / customs

Sunday, January 1st, 2012

Happy 2012 New Year . Wish to everyone best of luck, good health and best of success in the new upcoming year!
There is few customs, which are very typical for Bulgarian Christmas and New Year.
As I'm so keen on tradition and I'm sure many non-bulgarians are not aware of the Bulgarian custom, I'll try to name few of them and shed some light for foreigners who are about to celebrate the Christmas or New year eve in Bulgaria.

One is the back (spine) tapping, done by youngsters to elders with a stick made of cornel-tree and decorated in a very special beautiful way.

Here is how the stick the youngsters use to wish happy new year in a traditional bulgarian custom way.Survaknica Bulgariar New Year (Survane) new year custom
The back tapping to the elder is accompanied by famous words in Bulgarian saying:

Surva, Surva Godina!
Chervena Qbylka v Gradina,
edyr klas na niva,
golqm grozd na loza,
jylt mamul na lesa,
pylna kyshta s deca!
Jivo-zdravo do godina,
do godina do Amina!

This translated to english says something like:

Healthy (Complete), Healthy Year!
Red Apple in a Garden,
Large grapes in the vineyeard,
Yellow corn in the field,
full house with children!
Living-healthy until next year
in these year until the next one.

Actually this New Yearly wishings had different minor text variations in different regions of Bulgaria, but the main meaning is anyhow preserved.

Surva Surva Godina, Vesela Godina kid back tapping an older man Bulgaria
Kid using Survaknica to back tap some older man according to our tradition

You can see how simple and the same time meaningful those wishings are. They accent to the main things which were important for our forefathers. The things on which the yearly daily life depends.

Here is a video of some children in the kinder garden reciting the Surva, Surva wishing holding Survaknici

I've seen for the last 10 years these tradition as a consequence of the internationalization is starting to disappear. Now most of the times only in villages and some small regions these tradition is still practiced.
In cities gipsys are going in the early morning of the New Year morning and knocking on each apartment door offering a back tapping. Once they back tap you with Survaknica and wish you good things you're supposed to give them some food, candies and / or money 😉

Its also common that in the morning of the New Year a lot of folklore ensambles dance on the centers of cities and villages or sing Bulgarian folklore songs.

Bulgarian Folklore Choire

Some of the other things which are a kind of traditional on New Year is to go out on the city center and fire up some fires and dance some traditional dance we call Horo near the camping fire.


 

How to install and configure Jabber Server (Ejabberd) on Debian Lenny GNU / Linux

Wednesday, December 28th, 2011

Ejabberd server erlang logo hedgehog

I've recently installed a jabber server on one Debian Lenny server and hence decided to describe my installations steps hoping this would help ppl who would like to run their own jabber server on Debian . After some research of the jabber server softwares available, I decided to install Ejabberd

The reasons I choose Ejabberd is has rich documentation, good community around the project and the project in general looks like one of the best free software jabber servers available presently. Besides that ejabberd doesn't need Apache or MySQL and only depends on erlang programming language.

Here is the exact steps I followed to have installed and configured a running XMPP jabber server.

1. Install Ejabberd with apt

The installation of Ejabberd is standard, e.g.:

debian:~# apt-get --yes install ejabberd

Now as ejabberd is installed, some minor configuration is necessery before the server can be launched:

2. Edit /etc/ejabberd/ejabberd.cfg

Inside I changed the default settings for:

a) Uncomment%%override_acls.. Changed:

%%%% Remove the Access Control Lists before new ones are added.%%%%override_acls.

to

%%
%% Remove the Access Control Lists before new ones are added.
%%
override_acls.

b) Admin User from:

%% Admin user
{acl, admin, {user, "", "example.com"}}.

to

%% Admin user
{acl, admin, {user, "admin", "jabber.myserver-host.com"}}.

c) default %% Hostname of example.com to my real hostname:

%% Hostname
{hosts, ["jabber.myserver-host.com"]}.

The rest of the configurations in /etc/ejabberd/ejabberd.cfg can stay like it is, though it is interesting to read it carefully before continuing as, there are some config timings which might prevent the XMPP server from user brute force attacks as well as few other goodies like for example (ICQ, MSN , Yahoo etc.) protocol transports.

3. Add iptables ACCEPT traffic (allow) rules for ports which are used by Ejabberd

The minimum ACCEPT rules to add are:

/sbin/iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 5222 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 5222 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 5223 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 5223 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 5269 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 5269 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 5280 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 5280 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 4369 -j ACCEPT
/sbin/iptables -A INPUT -p udp -m udp --dport 4369 -j ACCEPT
/sbin/iptables -A INPUT -p tcp -m tcp --dport 53873 -j ACCEPT

Of course if there is some specific file which stores iptables rules or some custom firewall these rules has to be added / modified to fit appropriate place or chain.

4. Restart ejabberd via init.d script

debian:~# /etc/init.d/ejabberd restart
Restarting jabber server: ejabberd is not running. Starting ejabberd.

5. Create ejabberd necessery new user accounts

debian:~# /usr/sbin/ejabberdctl register admin jabber.myserver-host.com mypasswd1
debian:~# /usr/sbin/ejabberdctl register hipo jabber.myserver-host.com mypasswd2
debian:~# /usr/sbin/ejabberdctl register newuser jabber.myserver-host.com mypasswd3
debian:~# /usr/sbin/ejabberdctl register newuser1 jabber.myserver-host.com mypasswd4
...
etc.

ejabberdctl ejabberd server client (frontend) has multiple other options and the manual is a good reading.

One helpful use of ejabberdctl is:

debian:~# /usr/sbin/ejabberdctl status
Node ejabberd@debian is started. Status: started
ejabberd is running

ejabberctl can be used also to delete some existent users, for example to delete the newuser1 just added above:

debian:~# /usr/sbin/ejabberdctl unregister newuser jabber.myserver-host.com

6. Post install web configurations

ejabberd server offers a web interface listening on port 5280, to access the web interface right after it is installed I used URL: http://jabber.myserver-host.com:5280/admin/

To login to http://jabber.myserver-host.com:5280/admin/ you will need to use the admin username previously added in this case:
admin@jabber.myserver-host.com mypasswd1

Anyways in the web interface there is not much of configuration options available for change.

7. Set dns SRV records

I'm using Godaddy 's DNS for my domain so here is a screenshot on the SRV records that needs to be configured on Godaddy:

GoDaddy DNS SRV records screenshot

In the screenshto Target is the Fually qualified domain hostname for the jabber server.

Setting the SRV records for the domain using Godaddy's DNS could take from 24 to 48 hours to propagate the changes among all the global DNS records so be patient.

If instead you use own custom BIND DNS server the records that needs to be added to the respective domain zone file are:

_xmpp-client._tcp 900 IN SRV 5 0 5222 jabber.myserver-host.com.
_xmpp-server._tcp 900 IN SRV 5 0 5269 jabber.myserver-host.com.
_jabber._tcp 900 IN SRV 5 0 5269 jabber.myserver-host.com.

8. Testing if the SRV dns records for domain are correct

debian:~$ nslookup
> set type=SRV
> jabber.myserver-host.com
 ...
> myserver-host.com

 If all is fine above nslookup request should return the requested domain SRV records.
You might be wondering what is the purpose of setting DNS SRV records at all, well if your jabber server has to communicate with the other jabber servers on the internet using the DNS SRV record is the way your server will found the other ones and vice versa.

DNS records can also be checked with dig for example

$ dig SRV _xmpp-server._tcp.mydomain.net

[…]

;; QUESTION SECTION:
;_xmpp-server._tcp.mydomain.net. IN SRV

;; ANSWER SECTION:
_xmpp-server._tcp.mydomain.net. 259200 IN SRV 5 0 5269 jabber.mydomain.net.

;; ADDITIONAL SECTION:
jabber.mydomain.net. 259200 IN A 11.22.33.44

;; Query time: 109 msec
;; SERVER: 212.27.40.241#53(212.27.40.241)
;; WHEN: Sat Aug 14 14:14:22 2010
;; MSG SIZE rcvd: 111

9. Debugging issues with ejabberd

Ejabberd log files are located in /var/log/ejabberd , you will have to check the logs in case of any issues with the jabber XMPP server. Here is the three files which log messages from ejabberd:

debian:~$ ls -1 /var/log/ejabberd/
ejabberd.log
erl_crash.dump
sasl.log

I will not get into details on the logs as the best way to find out about them is to read them 😉

10. Testing ejabberd server with Pidgin

To test if my Jabber server works properly I used Pidgin universal chat client . However there are plenty of other multiplatform jabber clients out there e.g.: Psi , Spark , Gajim etc.

Here is a screenshot of my (Accounts -> Manage Accounts -> Add) XMPP protocol configuration

Pidgin account configuration XMPP on debian Linux
 

Poderosa a tabbed Terminal Emulator (PuTTY Windows Alternative)

Tuesday, December 6th, 2011

Even though, I rarely use Windows to connect to remote servers using SSH or Telnet protocols in some cases I’m forced to do that (in cases I’m away from my Linux notebook). I’m doing my best to keep away from logging anywhere via SSH using Windows as when using Windows you never know what kind of spyware, malware or Viruses is already on the system, not to mention Microsoft are sniffing a lot if not everything which is typed on the keyboard… Anyways, usually I use Putty as a quick way to access a remote SSH, however pitily PuTTY lacks an embedded functionality for Tabs and each new connection to a server I had to run a new instance of PuTTY. This is okay if you need to access a single server but in some cases where access to multple servers is necessery lacking the tab functionality and starting 10 times putty is really irritating and one forgets what kind of connection is present on which PuTTY instance.

Earlier on, I’ve blogged about the existence of PuTTY Connection Manager PuTTY add-on program which is a PuTTY wrapper which enables PuTTY to be used with Connection Tabs feature, however installing two programs is quite inconvenient, especially if you have to do this every few days (in case if travelling a lot).

Luckily there is another terminal emulator free program for Windows called PodeRoSA which natively supports a tabbed Secure Shell connections.
If you want to get some experience with it check out Poderosa’s website , here is also a screenshot of the program running few ssh encrypted connections in tabs on a Windows host.

Poderosa Windows ssh / telnet tabs terminal emulator screenshot
Another good reason that one might consider using Poderosa instead of PuTTY is the Apache License under which Poderosa is developed. Currently the Apache License is compatible with GPL free software license which makes the program fully free software. The PuTTY license is under BSD and MIT and some other weird custom license not 100% compatible with GPL and hence PuTTY can be considered less free software in terms of freedom.

How to debug mod_rewrite .htaccess problems with RewriteLog / Solve mod_rewrite broken redirects

Friday, September 30th, 2011

Its common thing that CMS systems and many developers custom .htaccess cause issues where websites depending on mod_rewrite fails to work properly. Most common issues are broken redirects or mod_rewrite rules, which behave differently among the different mod_rewrite versions which comes with different versions of Apache.

Everytime there are such problems its necessery that mod_rewrite’s RewriteLog functionality is used.
Even though the RewriteLog mod_rewrite config variable is well described on httpd.apache.org , I decided to drop a little post here as I’m pretty sure many novice admins might not know about RewriteLog config var and might benefit of this small article.
Enabling mod_rewrite requests logging of requests to the webserver and process via mod_rewrite rules is being done either via the specific website .htaccess (located in the site’s root directory) or via httpd.conf, apache2.conf etc. depending on the Linux / BSD linux distribution Apache config file naming is used.

To enable RewriteLog near the end of the Apache configuration file its necessery to place the variables in apache conf:

1. Edit RewriteLog and place following variables:

RewriteLogLevel 9
RewriteLog /var/log/rewrite.log

RewriteLogLevel does define the level of logging that should get logged in /var/log/rewrite.log
The higher the RewriteLogLevel number defined the more debugging related to mod_rewrite requests processing gets logged.
RewriteLogLevel 9 is actually the highest loglevel that can be. Setting the RewriteLogLevel to 0 will instruct mod_rewrite to stop logging. In many cases a RewriteLogLevel of 3 is also enough to debug most of the redirect issues, however I prefer to see more, so almost always I use RewriteLogLevel of 9.

2. Create /var/log/rewrite.log and set writtable permissions

a. Create /var/log/rewrite.log

freebsd# touch /var/log/rewrite.log

b. Set writtable permissons

Either chown the file to the user with which the Apache server is running, or chmod it to permissions of 777.

On FreeBSD, chown permissions to allow webserver to write in file, should be:

freebsd# chown www:www /var/log/rewrite.log

On Debian and alike distros:

debian:~# chown www-data:www-data /var/log/rewrite.log

On CentOS, Fedora etc.:

[root@centos ~]# chown httpd:httpd /var/log/rewrite.log

On any other distribution, you don’t want to bother to check the uid:gid, the permissions can be set with chmod 777, e.g.:

linux# chmod 777 /var/log/rewrite.log

Next after RewriteLog is in conf to make configs active the usual webserver restart is required.

To restart Apache On FreeBSD:

freebsd# /usr/local/etc/rc.d/apache2 restart
...

To restart Apache on Debian and derivatives:

debian:~# /etc/init.d/apache2 restart
...

On Fedora and derivive distros:

[root@fedora ~]# /etc/init.d/httpd restart
...

Its common error to forget to set proper permissions to /var/log/rewrite.log this has puzzled me many times, when enabling RewriteLog’s logging.

Another important note is when debugging for mod_rewrite is enabled, one forgets to disable logging and after a while if the /var/log partition is placed on a small partition or is on an old server with less space often the RewriteLog fills in the disk quickly and might create website downtimes. Hence always make sure RewriteLog is disabled after work rewrite debugging is no longer needed.

The way I use to disable it is by commenting it in conf like so:

#RewriteLogLevel 9
#RewriteLog /var/log/rewrite.log

Finally to check, what the mod_rewrite processor is doing on the fly its handy to use the well known tail -f

linux# tail -f /var/log/rewrite.log

A bunch of time in watching the requests, should be enough to point to the exact problem causing broken redirects or general website malfunction.
Cheers 😉

How to change mail sent from in Nagios on Debian GNU/Linux 6

Wednesday, August 24th, 2011

I’ve been playing with configuring a new nagios running on a Linux host which’s aim is to monitor few Windows servers.
The Linux host’s exim is configured to act as relay host to another SMTP server, so all email ending up in the Linux localhost on port 25 is forwarded to the remote SMTP.

The remote smtp only allows the Linux to send email only in case if a real existing username@theserverhostname.com is passed it, otherwise it rejects mail and does not sent properly the email.
As the newly configured Nagios installatio is supposed to do e-mail notification, I was looking for a way to change the default user with which Nagios sends mails, which is inherited directly after the username with which /usr/sbin/nagios3 and /usr/sbin/nrpe are running (on Debian this is nagios@theserverhostname.com).

Thanksfully, there is a work around, I’ve red some forum threads explaning that the username with whch nagios sends mail can be easily changed from /etc/nagios3/commands.cfg by passing the -a “From: custom_user@myserverhostname.com” to all occurance of /usr/bin/mail -s , its preferrable that the -a custom_user@myserverhostname.com is inserted before the -s “” subject option. Hence the occurance of mail command should be changed from:

| /usr/bin/mail -s "** $NOTIFICATIONTYPE$

To:

| /usr/bin/mail -a "From: custom_user@theserverhostname.com" -s "** $NOTIFICATIONTYPE$

Now to read it’s new configurations nagios requirs restart:

debian:~# /etc/init.d/nagios3 restart
...

Now in case of failed services or Hosts Down nagios will send it’s mail from the custom user custom_user@theserverhostname.com and nagios can can send mail properly via the remote relay SMTP host 😉

How to load custom Kernel (tun) module in CentOS and RHEL Linux

Thursday, July 14th, 2011

kernel module load on boot in CentOS and Fedora

Just recently it was necessery to load up a tun kernel module on few CentOS Linux servers.

I’m using Debian on daily basis, and everybody that had even little of experience with Debian should already be aware about the existence of the handy:
/etc/modules file.
On Debian to enable a certain kernel module to load up on Linux boot, all necessery is to just place the kernel module name in /etc/modules.
For example loading the tun tunneling kernel module I issue the command:

debian:~# echo tun >> /etc/modules

I wondered if CentOS, also supports /etc/modules as it was necessery now to add this tun module to load up on CentOS’s boot.
After a bit of research I’ve figured out CentOS does not have support for adding modules names in /etc/modules , anyhow after consulting CentOS documentation on http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-kernel-modules-persistant.html , I found CentOS and RHEL use /etc/rc.modules instead of Debian’s /etc/modules to load up any custom kernel modules not loaded by default during system boot.

Therefore instructing the RHEL Linux to load up my desired tun module in kernel on next boot was as easy as executing:

[root@centos ~]# echo 'modprobe tun' >> /etc/rc.modules
[root@centos ~]# chmod +x /etc/rc.modules

Now on next boot CentOS will load up the tun module in kernel. Achiving the same module load up is also possible through /etc/rc.local , but it’s not recommended way as /etc/rc.local would load up the kernel module after all of the rest init boot scripts complete and therefore will load up the module slightly later, at the final boot stage.

Runing sudo command simultaneously on multiple servers with SSHSUDO

Tuesday, June 21st, 2011

ssh multiple server command execute
I just was recommended by a friend a nifty tool, which is absoutely nifty for system administrators.

The tool is called sshsudo and the project is hosted on http://code.google.com/p/sshsudo/.

Let’s say you’re responsible for 10 servers with the same operating system let’s say; CentOS 4 and you want to install tcpdump and vnstat on all of them without logging one by one to each of the nodes.

This task is really simple with using sshsudo.
A typical use of sshsudo is:


[root@centos root]# sshsudo -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 yum install tcpdump vnstat

Consequently a password prompt will appear on the screen;
Please enter your password:

If all the servers are configured to have the same administrator root password then just typing one the root password will be enough and the command will get issued on all the servers.

The program can also be used to run a custom admin script by automatically populating the script (upload the script), to all the servers and issuing it next on.

One typical use to run a custom bash shell script on ten servers would be:


[root@centos root]# sshsudo -r -u root \
comp1,comp2,comp3,comp4,comp5,comp6,comp7,comp8,comp9,comp10 /pathtoscript/script.sh

I’m glad I found this handy tool 😉

How to set custom page titles in Joomla 1.5 manually for better SEO

Thursday, June 2nd, 2011

he Joomla CMS default behaviour is that Page titles of the Joomla Articles created are always set to the page Title assigned to each of the articles.

This is not very good behaviour in terms of SEO, as the page title of each link on the main page is different and there is no continuous repeating pattern in all of the joomla pages.
Everyone that has even basic idea of SEO knows that page titles are very important weight factor to make indexing inside Search Engines succesful.

There is a well know SEO rule which is the more reoccuring pattern one has in his page titles, more is stressed on the keywords contained in the title.
As I said for some weird reason Joomla has no common page Title for all my the created Article pages linked via the Main Menu*

Thus in order to improve this bad default Joomla SEO behaviour one has to change the default auto assigned titles for created pages, manually.

Two things are necessery to change each of the joomla already existing TITLES.

1. Go to each of the pages (.e.g. Home etc.) and change the Parameters System Page Title settings

After logging in with administrator in Joomla, navigate to Menus -> Main Menu*

Further on choose a menu item from all your existing items, let’s say Home and click on it.

On the left side below the Save, Apply, Close and Help buttons you will notice the menus:

Parameters (Basic), Parameters (Component), Parameters (System)

When clicked on Parameters (System) a submenu will appear:
Joomla Main Menu Parameters System Page Title better SEO

Above is a screenshot of the up-described Parameters (System) [Page Title] location

You need to change where it reads on the screenshot CHANGE THE TITLE HERE !!!!!! 😉

After entering your own desired page title go and save the article via the Apply or Save button (also visible in the screenshot).

Now as the custom Page Title is set, next step is to enable the custom Page Title for the respective Article in Article Manager

2. Enable custom Page Title for created pages in Joomla

Go to the Article Manager by following the menus:

Content -> Article Manager

Select the Article of which you want to change the Page Title to some custom text and click over it.

As the article opens for edit in an html editor, navigate to Parameters (Advanced) tab and therein change the Show Title from default setting value:
Use Global
to
Yes

Once again use the Save or Apply button to confirm the new settings and open your website in a new tab, try to browse and check the title of the articles parameters just edited. It should show up in the Title (page heading) the custom input Title.

Now repeat the same procedure for all pages (Articles), existing in Joomla to attune the Page Titles to some Google friendly strings and enjoy the better Search engine indexing which should likely follow.

What is Xorg’s server DPMS module for? And how to use it to reduce your computer power consumption

Thursday, April 21st, 2011

As I’m manually configuring a Xserver via xorg.conf I have noticed a block of code in:

Section "Monitor"
Identified "Generic Monitor"
Option "DPMS"
EndSection
That triggered my curiousity to research further what is DPMS . A very quick google search revealed that DPMS’s purpose is to communicate to communicate between the monitor and the computer, to make the computer turn off the (CRT or LED) based monitor if the computer is not used

Thus in short to rephrase DPMS is a power saving handy Xorg feature. I many custom configured xorg.conf like the mine I’m building right now does not include DPMS as many people doesn’t have idea what DPMS is and how to enable it.

DPMS is also an interface to the Energy start power-saving capability if not all, most of the modern day monitor screens.

DPMS enables the Xserver to control automatically the computer screen and thus reduces the overall computer power consumption.

To enable the use of DPMS on my Linux, all I had to do is place a couple of configuration directives in my xorg.conf .:
Here is how I enabled DPMS in my Xorg server:

1. Edit with a text editor /etc/X11/xorg.conf

2. Find the Monitor Section , e.g.:

Section "Monitor"
....
EndSection

3. Add inside the Monitor Section Options "DPMS" "true"

4. Lookup for the ServeryLayout section , e.g.:

Section "ServerLayout"
...
EndSection

5. Place inside the ServerLayout section For instance the following options:

Option "StandbyTime" "20"
Option "SuspendTime" "10"
Option "OffTime "25"

You might like to change the options StandbyTime, SuspendTIme or OffTime to match your likings.
6. As a last step restart the Xorg server.

Press Ctrl+Alt+BackSpace or by issuing:

host:~# pkill -HUP X

Test that DPMS is loaded properly by reviewing /var/log/Xorg.0.log for example:

host:~# grep -i /var/log/Xorg.0.log
(II) Loading extensions DPMS