Skip to main content

Database Connections made by IndiMail

IndiMail uses MySQL for storing information of virtual domain users. The table 'indimail' stores important user information like password, access permissions, quota and the mailbox path. Most of user related queries have to lookup the 'indimail' table in MySQL.
Rather than making individual connections to MySQL for extracting information from the 'indimail' table, IndiMail programs use the service of the inlookup(8) server. Programs use an API function inquery() to request service. InLookup is a connection pooling server to serve requests for inquery() function. It is implemented over two fifos. One fixed fifo for reading the query and reading the path of a randomly generated fifo. The randomly generated fifo is used for writing the result of the query back. inlookup(8) creates a read FIFO determined by the environment variable INFIFO. If INFIFO is not defined, the default FIFO used is /var/indimail/inquery/infifo. inlookup(8) then goes into an infinite loop reading this FIFO. If INFIFO is not an absolute path, inlookup(8) uses environment variable FIFODIR to look for fifo named by INFIFO variable. Inlookup(8) can be configured by setting environment variables in /service/inlookup.info/variables
  • inlookup helps in optimizing connection to MySQL(1), by keeping the connections persistent.
  • It also maintains the query result in a double link list.
  • It uses binary tree algorithm to search the cache before actually sending the query to the database.
  • IndiMail clients send requests for MySQL(1) queries to inlookup through the function inquery() using a fifo.
  • The inquery() API uses the InLookup service only if the environment variable QUERY_CACHE is set. If this environment variable is not set, the inquery() function makes a direct connecton to MySQL.
  • Clients which are currently using inquery are qmail-smtpd(1), proxyimap(8), proxypop3(8), vchkpass(8) and authindi(8).
  • inlookup(8) service is one of the reasons why IndiMail is able to serve million+ users using commodity hardware.
The program inquerytest simulates all the queries which inlookup supports and can be used as a test/diagnostic tool for submitting queries to inlookup. e.g
% sudo inquerytest -q 3 -i "" user@example.com



Post a Comment

Popular posts from this blog

IndiMail Installation for newbies in < 10 steps

Installing Indimail using YUM/APT Repository Install OS
OpenSUSE
openSUSE Leap 42.3
openSUSE Leap 42.2
openSUSE 13.2
openSUSE 13.1
SUSE Linux Enterprise 12 SP2
SUSE Linux Enterprise 12 SP1
SUSE Linux Enterprise 12
Red Hat
Feodra 27
Fedora 26
Red Hat Enterprise Linux 7
Red Hat Enterprise Linux 6
CentOS 7
CentOS 6
Debian
Debian 8.0
Debian 7.0
Ubuntu 17.04
Ubuntu 16.10
Ubuntu 16.04
Ubuntu 14.04
Ubuntu 12.04
Click the below URL for Install Instructions
https://software.opensuse.org/download.html?project=home%3Aindimail&package=indimail Shutdown MySQL if already running and disable MySQL from being started up by the system % /etc/init.d/mysqld stop % sudo chkconfig mysqld off % /bin/rm -f /service/mysql.3306/down
Start IndiMail
% sudo service indimail start Check Servicess
% sudo /usr/bin/svstat /service/* /service/clamd: up (pid 1014) 2985 seconds /service/dnscache: up (pid 1021) 2985 seconds /service/fetchmail: down 2985 seconds /service/freshclam: up (pid 1020) 2…

Using Docker Engine to Run IndiMail / IndiMail-MTA

IndiMail now has docker images. You can read about installing Dockerhere. Once you have installed docker-engine, you need to start it. Typically it would be
$ sudo service docker start
To avoid having to use sudo when you use the docker command, create a Unix group called docker and add users to it. When the docker daemon starts, it makes the ownership of the Unix socket read/writable by the docker group.
Warning: The docker group is equivalent to the root user; For details on how this impacts security in your system, see Docker Daemon Attack Surface for details.$ sudo groupadd docker $ sudo usermod -aG docker your_username
Log out and login again to ensure your user is running with the correct permissions. You can run the unix id command to confirm that you have the docker group privileges. e.g.
$ id -a uid=1000(mbhangui) gid=1000(mbhangui) groups=1000(mbhangui),10(wheel),545(docker) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
Now we need to pull the docker image for I…

Writing Filters for IndiMail

IndiMail provides multiple methods by which you can intercept an email in transit and modify the email headers or the email body. A filter is a simple program that expects the raw email on standard input and outputs the message text back on standard output. The program /bin/cat can be used as a filter which simply copies the standard input to standard output without modifying anything. Some methods can be used before the mail gets queued and some methods can be used before the execution of local / remote delivery.

It is not necessary for a filter to modify the email. You can have a filter just to extract the headers or body and use that information for some purpose. IndiMail also provides the following programs - 822addr(1), 822headerfilter(1), 822bodyfilter(1), 822field(1), 822fields(1), 822header(1), 822body(1), 822headerok(1), 822received(1), 822date(1), 822fields(1) to help in processing emails.

Let us say that we have written a script /usr/local/bin/myfilter. The myfilter program …