Courier Mail Server – Mail in your network!


Frequently Asked Questions

  1. Question:

    Message of failure to start SMTP/POP3 service because IP address/port is occupied appears when CMS starts. How to start it?


    Most likely, some other application using this address/port is running. It can be mail server, proxy server, firewall or antivirus monitor. You should shutdown it, or set it or CMS services to other IP addresses/ports.

    Run the command netstat -a -b -n -p TCP >ports.txt, to get in the file ports.txt the list of open ports and applications that opened them. The executing of command may take several minutes.

  2. Question:

    CMS services are started, but message "Could not connect to the server" appears when sending/receiving mail from other computer. How to solve this problem?


    Try to connect to services from this computer using telnet program. To do this in Start menu click Run command and enter: telnet address port, where address is the IP address of computer with CMS and port is number of SMTP or POP3 service port (standard values are 25 and 110 accordingly). In telnet program window a line starting with "220" characters for SMTP service and "+OK" for POP3 service shall appear. This line shall also contain host name or IP address of computer with CMS. In this case the corresponding service is available from this computer. Check mail client settings; the username or password may be incorrect.

    If connection to the server with telnet program failed, the problem might be due to the server settings (or if it is not started) or network troubles. Check the server settings, view the log — it contains connections/disconnection of clients.

  3. Question:

    Is it possible to connect to CMS over the remote access?


    Yes, to do that you should know the IP address of the remote computer that has CMS running. To find it out, connect to the remote computer and execute ping <remote computer name> command. The received IP address (usually should be used as SMTP/POP3 server address.

  4. Question:

    I have mail domain that is registered by provider. Messages addressed to come to one address — How do I adjust CMS to distribute messages from this remote mailbox between local users according to the name parameter?


    Create local domain in CMS and users of this domain. Create remote mailbox Select "Extract local recipients from these header fields" check box on "Recipients" tab of its properties and specify necessary fields.

  5. Question:

    Why cannot mail sometimes be deleted from the mailbox after it is received? Properties of the remote mailbox have only check box "Remove messages from mailbox" selected.


    Due to special features of POP3 protocol, the remote server physically deletes messages provided only the connection is successfully terminated. If messages remained in the remote mailbox, the connection with POP3 server was broken. CMS keeps received messages protocol; they will not be received repeatedly and will be deleted during next connection session.

  6. Question:

    How do I duplicate all incoming/outgoing mail to certain addresses?


    Create a new sorter with two rules; the first one will direct the messages to the current main sorter, the second one will add the recipient for copying of whole mail. If there is several such recipients, create several rules or use the aliases. Then assign created sorter as main sorter.

  7. Question:

    Why is remote mail received from three first mailboxes only?


    It can happen if mailboxes are located on the same POP3 server that can have at most three simultaneous connections from one IP address. Set "Max. number of simultaneous connections" parameter to three in the properties of CMS remote POP3 server.

  8. Question:

    Sending mail to external addresses fails; "550 Relaying prohibited" message appears. What does that mean?


    It means that this client is not allowed to send external mail in CMS. If the user is registered in CMS, his properties allow sending mail. At that, user's mail client shall have SMTP authentication activated. If the user is not registered in CMS, add IP address of his computer into group of IP addresses to whom sending of external mail is allowed (SMTP Service/Additional).

  9. Question:

    Is there a web interface for users to register on the server independently?


    No. It will be implemented in the future versions of CMS.

  10. Question:

    Why does users authentication of secondary domains fail?


    Specify full username: user@domain.

  11. Question:

    When sending the mail to certain SMTP servers CMS returns the error of the type "501 sender address must match authenticated user" and messages are not sent. How do I correctly adjust the sending to such servers?


    The specified error returns by SMTP servers requiring that sender address of the message coincided with name of authenticated user. In other words they require that their users sent the mail only under their own name.

    Often similar restriction set the large Internet services in purposes of the fight with sending of the spam and forged messages.

    If your provider (hoster) gives you the access to his SMTP server not having the said restriction then sending of the whole external mail in CMS advisable to adjust exactly through it.

    However CMS can be adjusted and for sending to servers with given restriction. Assume that you have remote mailbox with the address Corresponding SMTP and POP3 servers: and Adjust the CMS as follows:

    • Create SMTP server, herewith clear the check box "Authentication" and select the check box "Personal authentication".
    • Create the sending queue, for example "To", herewith select "on list" and add to the list only.
    • Create POP3 server
    • Create the remote mailbox, herewith fill the fields "E-mail address", "User" and "Password". The rest mailbox properties are not used when sending and can have any value.
    • Create the rule in the main sorter:
      If: From:"" AND If message has external recipients, Perform actions only for these recipients, Store message to this queue: "To", End message sorting.
    • Then create as usually task and schedule in the scheduler for sending the mail from queue "To".

    Now CMS will be able to send messages to server for any external recipients but only from sender (or from any local user for which such external address is assigned).

    To allow the sending from other your addresses of domain is enough to create corresponding remote mailboxes in CMS.

    To allow the sending from your addresses of other domain (for example is necessary to perform for this domain all actions enumerated above.

The site is updated: 01.11.2023
Current version of CMS: 3.11 (?)
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 27.10.2023  Released CMS 3.11.
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