Hi Zhang...Thanks for your reply. In continuation to your Here are the features im looking for my application.

1) I want to search for a specific string on the subject field and if the match is found, move the email to a particular predefined folder say "Test".  I want this feature to be enabled for all users within the domain so that the feature is similar for all the users.  My Mobile application will be pointed to the "Test" folder to read the emails which matches the string criteria.  So i should be able to write sieve rules such a way that the rule applies to all users in domain at admin level rather than individual users at user level.
You mentioned i should be able to do this using webmail.  Does it mean can i login to webmail as admin and enable sieve rules for all users within domain?
Also when you refer webmail, is it different from Roundcube used by users?

Hi Zhang...Thanks again.  I installed iredmail on VM.  I had setup some filters on round cube and they apply only for individual user.  How can i setup global sieve rules which applies to all users?  Do i need to enable "sieve rules" plugin or "manage sieve" plugin should be enough to write global rules?  Do you have any document which helps to write global sieve rules?

Thanks for the document.  I created some global Sieve rules.  How should i apply those global sieve rules?  On which file should i write these global sieve rules?

I tried on below file but they do not work.

/var/lib/dovecot/sieve/default.sieve

Also some articles mentioned about the below file but i cannot write any rules to this file as it says i cannot write to this file.

/etc/dovecot/sieve/default.sieve

Hi Zhang....

That works....thanks for that....

Is there a way to create a folder like "Important" globally for all users at server level?  As and when i create a user that user should have this folder "Important" along with all other folders like Inbox etc.., 

Can we do this globally for all users so each user gets his own personal "Important" folder?

Hi Zhang,

Thanks again for you reply.  I tried based on your instructions.  I copied the Sent folder script for folder "Important" in between Junk and Archive section as mentioned below.  However when i create a new user, i did not see important folder created in his mailbox when i logged in through roundcube.  I rebooted the server to see if that would help and after the reboot i lost access to web access both admin and round cube users and it was throwing error "connection to storage server failed".

I removed the "Important" folder script which i added and rebooted the server again and I'm able to login now using round cube.

Could you please see if I'm using the right syntax and placing it on the right file?

vim /etc/dovecot/dovecot.conf

    mailbox "Junk E-mail" {
        auto = no
        special_use = \Junk
    }
  mailbox Important {
        auto = subscribe
        special_use = \Important
    }
    # Archive
    mailbox Archive {
        auto = no
        special_use = \Archive
    }

Hi Zhang...Thanks for the reply and all your support.  I tried without "special_use" and then it works. 

Is it possible to write "And" filter in Sieve rules?  Like checking a particular string (abc) on subject field "AND" checking a string (xyz) on body of the email?   I was reviewing the sieve rules document but could not find any thing related to AND conditions.  I can only see the sieve rules where it checks only one condition.  If it is not possible with sieve rules, do you have any recommendations?

Hi Zhang,
I tried looking at the syntax on the Roundcube webmail but i did not see right syntax for my requirements.  Appreciate if you can help me or direct me to the documentation where i can look for the right resources to setup AND filter on Sieve rules.
What I'm seeing currently on Roundcube webmail is provided below.  I also looked on some documents on internet but no luck.  It can search "any of" or "all of" in both the subject and body messages for all the conditions.  But in my case I'm looking for match with any of the condition.

Current Roundcube Syntax:
1)
require ["body","fileinto"];
if allof (header :contains "subject" "abc", header :contains "subject" "def", body :text :contains "123", body :text :contains "456")
{
    fileinto "Important";
}
2)
require ["body","fileinto"];
if anyof (header :contains "subject" "abc", header :contains "subject" "def", body :text :contains "123", body :text :contains "456)
{
    fileinto "Important";
}

However

My requirement:

if anyof (header :contains "subject" "abc", header :contains "subject" "def")
AND
if anyof (body :text :contains "123", body :text :contains "456)
fileinto "Important";

This AND condition match is something key for my requirement as i need to search both subject and body.

Appreciate all your support.

Hi Zhang,
Appreciate all your help so far.
We have a web application which wants to make a call to the user mailbox folders and display the emails within that folder on the web application.  It is similar to roundcube but we want to use our own web application instead of round cube.  Can our web application make a call to the mail server and pull the contents of the folder and display emails?  If so where should we point our web server to the email server (path)?

If respective folders is not possible, can web server make a call and pull the entire user mailbox?  If so where should we point our webserver to make a call to email server to pull the contents of the mailbox for that respective user?

Also can the web server authenticate with the email server LDAP database before pulling the mailbox contents after successful authentication?

So where should we point the IMAP query?  Do you have information about the destination path or folders on the Mail server we need to point the IMAP query from the web server?

FYI: https://docs.iredmail.org/network.ports.html

Yes you can modify files under mailbox directly, default directory is /var/vmail/vmail1/<domain>/...

WARNING: MODIFYING MAIL MESSAGE DIRECTLY IS NOT RECOMMENDED, USE IMAP PROTOCOL INSTEAD PLEASE.