Samurai Penguin's Lair 2008-10-07T00:29:12Z James Ber Copyright 2008, James Ber SPHPBLOG Sorry for the downtime... http://www.samurai-penguin.com/index.php?entry=entry080722-074906 2008-07-22T00:00:00Z 2008-07-22T00:00:00Z Custom Bash Prompt


The comments pretty much cover how it works, with the memory working the same as the load average. It does require the ‘ansicolor’ library, which I borrowed and improved from ubuntuforums. It’s quite useful for bash programming. This makes it trivial to customize the prompt. Set the colors you want at the top under the PROMPT_COLOR variables. I’ve included two variations(one commented) in the script, so I can tell which machine I’m on at a glance.

Click here to download the code]]> http://www.samurai-penguin.com/index.php?entry=entry080512-070238 2008-05-12T00:00:00Z 2008-05-12T00:00:00Z Deep Thoughts... ]]> http://www.samurai-penguin.com/index.php?entry=entry080512-065739 2008-05-12T00:00:00Z 2008-05-12T00:00:00Z Ubuntu MailServer Part 1: Making Postfix and Dovecot play nice Ubuntu Wiki.


Installing Core Software


First, we'll want to install the core programs that will be our mailserver. To do this:

sudo aptitude install postfix mailx dovecot-common dovecot-imapd dovecot-pop3d whois

This may take a few minutes to complete.

Configuring postfix


Now, we'll tell postfix how we want it to work. First, we're going to tell it where to store mail, and how to figure out what mailbox belongs to what user. Add the following lines to /etc/postfix/main.cf:

home_mailbox = Maildir/
virtual_mailbox_domains = /etc/postfix/vhosts
virtual_mailbox_base = /home/vmail
virtual_mailbox_maps = hash:/etc/postfix/vmaps
virtual_minimum_uid = 1000
virtual_uid_maps = static:5000
virtual_gid_maps = static:5000


The virtual lines all imply that we're not applying a specific domain, but that it needs to read various files to find the user/domain names that it accepts mail for. Let's go ahead and create those files:

/etc/postfix/vhosts: Here, insert a list of all the domains you're hosting, each on its own line. For example:

example.com
example.net
samurai-penguin.com

and so on.

/etc/postfix/vmaps: Now we specify both the email addresses we host, and the paths to them. You should always use the domain.com/user paths to keep things straight. Example:

abuse@example.com example.com/abuse/
postmaster@example.com example.com/postmaster/
you@example.net example.net/you/

IMPORTANT: Make sure to postmap the vmaps file every time you change it so that postfix can use it. Run the following command to do this:

sudo postmap /etc/postfix/vmaps

Finally, we need to setup the mailbox user/group so that both postfix and dovecot can read the mail directories.

sudo groupadd -g 5000 vmail
sudo useradd -m -u 5000 -g 5000 -s /bin/bash vmail

Configuring Dovecot


For the dovecot configuration, there are a LOT of changes, so it's easier to simply copy over the configuration file. Download this file, backup your old /etc/dovecot/dovecot.conf file, and write this one.

Dovecot.conf

What this does, essentially, is make dovecot play by the same rules we just told postfix to play by as far as how to recieve mail, where to look, etc. We also tell it where to find it's username/password information.

Adding Users


Now it's time to actually create some users. This is a two step process(really 3). The first step is to add the domain name to postfix's /etc/postfix/vhosts file. If it's already there, then just skip that.

For sanity, take a look at the configuration formats for the dovecot users. In reality, you'll never have to touch these because we're going to automate the whole process.

/etc/dovecot/users
info@domain1.com::5000:5000::/home/vmail/domain1.com/:/bin/false::

/etc/dovecot/passwd:
info@domain1.com:$1$G/FqlOG5$Vj0xmc9fKY.UVr8OWr/7C1

As I mentioned, you can/should use this script to do it all for you. It takes care of adding the user to postfix and postmapping the config file, as well as setting the password for the dovecot user. Note that it doesn't actually create folders -- postfix will do that for us.

adddovecotuser

Copy this file to somewhere like /usr/local/bin, and make sure it's executable (chmod +x adddovecotuser). You have to run this script as root/sudo. To add a user:

sudo adddovecotuser user@domain.com

So long as the domain is in /etc/postfix/vhosts, that's it! You should now have a mailserver that can recieve mail for you. That's great and all, but there are still a few limitations which will be covered in subsequent HOWTO articles:

- No Spam Filtration
- No Blocklists
- No way to send mail from outside
- No Antivirus scanning
- No Webmail
Good luck, and feel free to post comments if you have any questions!]]> http://www.samurai-penguin.com/index.php?entry=entry080509-114157 2008-05-09T00:00:00Z 2008-05-09T00:00:00Z Bash one-line script to find common referrers
grep "/page.html" access.* | awk '{print $11}' | sort | uniq -c | sort -n

Basically, this checks for all requests to page.html in all access logs. It then spits out only the 11th column(referrer), then counts and sorts.

Other useful columns (assuming that you're using the standard "combined" log format:
- $1 - IP address
- $12+ - user agent
- $6 - request type(GET, POST, PUT, etc.)

This can be useful in a number of different ways. For example, trying to find abusive behaviors can be done by looking for a lot of POST and PUT requests from a specific IP:

grep "POST\|PUT" access.* | awk '{print $1}' | sort | uniq -c | sort -n

Hopefully this is of use to someone!]]> http://www.samurai-penguin.com/index.php?entry=entry080505-145544 2008-05-05T00:00:00Z 2008-05-05T00:00:00Z Welcome... http://www.samurai-penguin.com/index.php?entry=entry080504-213114 2008-05-05T00:00:00Z 2008-05-05T00:00:00Z