The RPOP module can be used when the CommuniGate Pro Server has a dial-up connection with dynamically assigned IP address, and thus the Server cannot receive mail via SMTP. The RPOP module polls the specified remote host (ISP) accounts, retrieves messages and stores them in the Server mailboxes.
The RPOP module is useful even if the CommuniGate Pro Server has a full-time Internet connection. A user that has several accounts on several hosts can instruct the RPOP module to poll those accounts, so all their mail is collected in their CommuniGate Pro account.
The RPOP module supports Domain-Wide Accounts. A Domain-wide account is an account on the ISP or any other host that collects all messages sent to your domain. The RPOP module retrieves all messages from such an account and distributes them based on the addressing information in the message headers. The RPOP module can poll several Unified Domain-Wide Accounts.
The RPOP module activity can be limited using the TCP Activity Schedule. The module does not poll any remote account till the TCP Activity Schedule allows the Server to initiate outgoing network connections.
Use a Web browser to configure the RPOP module.
Click the Update button to modify the RPOP module settings.
If a mail account on an external host collects mail directed to all users of your domain, the RPOP module can be instructed to retrieve mail from that account and distribute it to local users.
Standard POP servers accept incoming connections on the TCP port 110.
If you need to poll an account on a remote POP server that uses a non-standard port, specify
the port number after the host name, using the colon (:) symbol as the separator:
There is always an empty row in the Unified Accounts table. Use it to specify a new Unified Account. To remove an account, set the Poll Every option to never.
Click the Update button to modify the RPOP module list of the Unified Domain-Wide Accounts.
When a message is sent via the Internet, the information about the sender and the message recipients is sent in the so-called mail envelope. If mail is sent via SMTP, the envelope is sent as a sequence of the protocol commands, if mail is sent via UUCP, the envelope is sent using additional files. The information in the envelope is usually the same as the information in the message headers, but it is not always true. The most important exceptions are:
When a message is stored in a mailbox, the envelope information about the sender is added to the message headers as the Return-Path header field. Usually, the envelope information about the recipients is not added to the message headers.
When the RPOP module retrieves a message from a Unified Domain-Wide Account, it has to recompose the message envelope and deliver the message to its final recipient. If the message contains the Return-Path header field, the address in that field is placed in the new envelope as the sender's address, and the header field is removed from the message (it will be recreated when the message is delivered to its final destination).
If a Unified Domain-Wide Account is created with the mail system that can copy the recipient addresses from the envelope into some message header field, then the delivery via RPOP is as reliable as SMTP and UUCP delivery. Enter the name of that header field into the Unified Account settings, and the RPOP module will look for that field in all messages retrieved from that account. The addresses from that field will be placed into the new envelope and the messages will be directed to those addresses. The header field itself is removed from the message.
All Stalker mail servers can be used to create Unified Domain-Wide Accounts. For those accounts, the envelope recipients are added to the message headers as the X-Real-To fields.
A popular sendmail system can be configured to add X-Real-To header fields, too (See the Appendix A).
If the host system cannot store envelope recipients in the message headers, leave the Special-Header field empty. In this case, the RPOP module will search for all To:, Cc: and Bcc: header fields in a retrieved message. It will use the addresses from those fields only if the domain name in those addresses can be routed to any non-SMTP module of the CommuniGate system. If the address is routed to the SMTP module, or the address cannot be routed at all (unknown user, etc), the RPOP module does not send any error messages to the sender, but simply ignores the address.
As explained above, this can cause problems when envelope addresses are not the same as the addresses in the message headers. Besides, some systems do not process the Unified Accounts correctly, so if a message is sent to three users in your domain, those systems store three copies of the message in the Unified Account mailbox. Since each message header contains the addresses of all three users, the RPOP module will deliver three copies of the message to each user.
The problems with Bcc, mailing lists, and duplicated message can be very annoying, so we strongly recommend you to ensure that the provider's mail system adds envelope information to the messages stored in your Unified Domain-Wide Account.
The CommuniGate Pro RPOP module can poll POP accounts on remote hosts on behalf of the CommuniGate Pro users. For each user an unlimited number of external accounts can be specified. The accounts can be specified by the Server administrator, via a link on the Account settings page, or by the user themselves, via the User Web Interface, if the right to specify remote accounts has been granted to the user by the administrator.
The settings are the same as for the Unified Accounts, but the Special Header field is not presented. All messages retrieved on the user behalf are directed to that user, regardless of the message header contents.
The following file can be used to force sendmail to store the envelope information in the messages headers.# This file should be placed into the directory cf/feature from
After these updates are applied, make sure that sendmail delivers all mail for you domain to one account on the sendmail system. The sendmail configuration for that unified account should list the 'mailer' marked with the 'T' flag.