Archive for the ‘linux’ Category
I configure DKIM on Postfix using the Ubuntu.
1. Install dkim
sudo apt-get update sudo apt-get upgrade sudo apt-get install opendkim opendkim-tools
2. Configure /etc/opendkim.conf
Domain yourdomain.com KeyFile /etc/mail/mail.private Selector mail
3. Configure /etc/default/opendkim file
Add to the end of the file.
4. Configure /etc/postfix/main.cf file
Add these configuration options to the end of the main.cf file.
# DKIM milter_default_action = accept milter_protocol = 2 smtpd_milters = inet:localhost:8891 non_smtpd_milters = inet:localhost:8891
5. Create directory /etc/mail and go there with
6. Generate keys in /etc/mail
sudo opendkim-genkey -t -s mail -d youdomain.com
After generating keys you’ll have mail.private and mail.txt in the directory.
mail.private is your private key and
mail.txt is the public key that you should set as TXT record of the domain.
7. Configure your domain TXT record for DKIM
mail.txt contains what you should set for the domain. It contains something like this:
mail._domainkey IN TXT "v=DKIM1; k=rsa; t=y; p=MIG...QAB" ; ----- DKIM key mail for youdomain.com
This means that you need to create TXT record for you domain that has mail._domainkey as a “host name” and v=DKIM1; k=rsa; t=y; p=MI…AQAB as a “ip address/url”.
7. Start opendkim and restart Postfix
sudo service opendkim start sudo service postfix restart
8. Useful links
Often, when I want to access my remote DigitalOcean server I have to find out the IP address of it. It isn’t comfortable for me so I decided to create a short alias for this IP in /etc/hosts. Now, after I’ve just made an alias, it’s really more comfortable and faster to login to the remove server via ssh.
127.0.0.1 localhost 127.0.1.1 infous-desktop 220.127.116.11 your_alias
Login via ssh using the alias
The another way to set the ssh alias is to edit the ~/.ssh/config file.
Host your_alias Hostname 192.0.2.1
Then to login just type:
But there’s a shorter way. Again, edit ~/.ssh/config and set:
Host your_alias Hostname 18.104.22.168 User your_user
Now, you can login to your remote host via ssh like:
Thanks to everybody that commented this little note and suggested more elegant solutions!
I use Ubuntu 11.10 and in this short note I will provide steps to install PhpStorm.
1. Install Java
sudo add-apt-repository ppa:webupd8team/java sudo apt-get update sudo apt-get install oracle-java7-installer
And check that Java’s been installed well:
2. Download PhpStorm for Linux. You will download PhpStorm-5.0.4.tar.gz or something like this. BTW, I download it using Google Chrome.
3. Click on the downloaded archive so that Archive Manager will be opened. Extract all files to
~/PhpStorm/ if you don’t have this folder create it.
Don’t uncheck “Re-create folders” and “Overwrite existing files”. Everything should be like on the screenshots above. Otherwise the folder structure will be broken and you might get the error, when you’re launching
Error: Could not find or load main class com.intellij.idea.Main
4. After the PhpStorm archive has been extracted quit the Archive Manager.
5. Open the Terminal and find phpstorm.sh inside
~/PhpStorm/PhpStorm-121.390/bin/ folder and run it:
Congratulations, PhpStorm should be installed and launched!
Very often you need to send mail only. For example, your web site sends some notifications by email only. In this case, there’s a reason to configure you MTA (main transfer agent) only to send emails.
In case of Postfix, only some options should be edited to force your Postfix to send mail only.
inet_interfaces = loopback-only mydestination =
Comment existing inet_interfaces and mydestination if they’re exist by using # at the beginning of the line.
Don’t forget to reload Postfix:
sudo /etc/init.d/postfix reload
For more information you may read Postfix on a null client.
Here’s a quick guide of installing Postfix (Mail Transfer Agent) on Ubuntu Linux.
To install Postfix type this command:
sudo apt-get install postfix
/etc/postfix/main.cf is a main configuration file.
At least, configure a hostname in
To find out the value of some configuration option type this command, for example, find out the
postconf -d myhostname
After all the changes have been made to
main.cf you should restart the Postfix to apply the changes:
sudo /etc/init.d/postfix reload
Before all of the things you need Linux and something like Postfix installed. I test these examples on Ubuntu.
In the first example, we will create a file with the message and then we’ll send it to the recipient with help of sendmail command.
Create the file /tmp/mail.txt that contains the text and a new line at the end:
sudo nano /tmp/mail.txt
Subject: the subject This is the text of the message. [new line]
Then type this:
sendmail firstname.lastname@example.org < /tmp/mail.txt
I’ve tryed to use some GD functions in php. Locally everything is ok, I use xampp on Windows. But when I moved my site to the server I get this error:
PHP Fatal error: Uncaught exception ‘WideImage_Exception’ with message ‘WideImage requires the GD extension, but it’s apparently not loaded…
In my php app the WideImage library is used and it utilizes GD library. So, there isn’t GD extension installed. Well, let’s install it:
apt-get update apt-get upgrade --show-upgraded apt-get install php5-gd
After installing php5 gd library the error have been gone and WideImage classes begin to work properly.
PHP has lots of libraries and modules. To list them you can use this command:
apt-cache search php5-
Then you will see:
php5-cgi - server-side, HTML-embedded scripting language (CGI binary) php5-cli - command-line interpreter for the php5 scripting language php5-common - Common files for packages built from the php5 source php5-curl - CURL module for php5 php5-dbg - Debug symbols for PHP5 php5-dev - Files for PHP5 module development php5-gd - GD module for php5 php5-gmp - GMP module for php5 php5-ldap - LDAP module for php5 php5-mysql - MySQL module for php5 [...]
If you want to install a module run the command:
sudo apt-get install module-or-library-name
It’s possible to install several modules or libraries at once just separate them with a space.
I’ve just tried to understand what’s the problem with my crontab. I set it to a proper time but nothing happens. As i guessed the problem is in timezone.
I use Debian linux so here I’ll provide steps how I’ve fixed it:
Configure time zone with dpkg-reconfigure
Link localtime to a corresponding zoneinfo file
ln -sf /usr/share/zoneinfo/Europe/Kiev /etc/localtime
In your case select your time zone.
Restart cron daemon
In my case this was the fix for the problem. I edited my contab and cron started to work like a Swiss watch