The CommuniGate POP is a CommuniGate communication module supporting E-mail message transfer using the POP3 Internet protocol (RF1939, RFC1725) via TCP/IP networks. MIME (RFC 1341) support and various attachment encoding methods are provided with the CommuniGate Server kernel itself.
The CommuniGate POP module supports multi-stream communications. For each registered user, POPGate can retrieve messages from several remote mailboxes. CommuniGate POP can retrieve mail for your entire domain using so-called "Unified Domain-wide accounts" and distribute it.
The CommuniGate POP module can operate as a POP3 server, provide access to CommuniGate user mailboxes for several remote users simultaneously. It can also provide access to Unified-Domain wide accounts.
The latest version of the CommuniGate POP module can be downloaded from:
<http://www.stalker.com>
or
<ftp://ftp.stalker.com>
To be notified about updates: send any message to <mailto:cgate-on@stalker.com>
Retrieving Mail
Sometimes (usually when your CommuniGate server is using dial-up connections to the Internet), mail is stored on some foreign "mail servers". The POP protocol allows client applications to connect to those mail servers and retrieve mail from mailboxes on those servers.
For dial-up linked system, you will use POP to retrieve your mail from the mail server(s), and you will use SMTP to send your mail. When a dial-up (PPP, SLIP) link is used, the CommuniGate POP module initiates dial-up connections only when it is allowed by the schedule set with the "TCP Schedule" CommuniGate Server settings.
Each registered CommuniGate user can specify the POP account(s) he/she has on remote mail servers, and CommuniGate POP will automatically make connections, retrieve new mail and store mail in user's In Box mailboxes.
If you do not have your own domain name, but use mailbox(es) on the host computer (i.e.,. if your mailboxes have names like <yourname>@<provider.host.name>), then enter the provider host name as your own Domain Name in the General Server settings.
Note: the domain name in your mailbox name should be the name of a real machine on the provider host (the so-called A-record). The domain name used to address mail to your provider system (MX-record) can be different. For example, mail to a mailbox on your provider system can be sent to user@xxxx.com, but the provider machine that actually keeps mailboxes can have a different name, for example pop.xxxx.com. In this case you should specify user@pop.xxxx.com as your POP account name.
Unified Domain-Wide Account
When you have many local users, you may consider getting your own domain name. In this case your network provider can store all messages directed to your domain in one POP account.
The CommuniGate POP module can retrieve mail from such a "unified", domain-wide account. When specified, that account is polled periodically, and all messages retrieved from that account are delivered to the CommuniGate users.
When you get your own domain name, do not forget to enter it in the CommuniGate Server GENERAL settings. CONTACT YOUR NETWORK PROVIDER TO GET YOUR OWN DOMAIN NAME and a UNIFIED DOMAIN-WIDE POP ACCOUNT.
Usually the message "envelope" information is lost when messages are stored in a POP account, so the CommuniGate POP module has to rely on the information stored in the To: and Cc: fields of retrieved messages. If addresses in those fields are username@your.domain.name, the message is routed automatically. Otherwise the CommuniGate POP module does NOT route a message retrieved from that account, instead that message is routed to the CommuniGate Postmaster.
Some systems can store the actual envelope information when they store messages in POP accounts. The envelope information is usually stored in the field named "X-Real-To:" or "X-Apparently-To:". If your provider system has this feature, enter the name of that field in the Special Header setting in the CommuniGate POP Service Settings. In this case, the To: and Cc: fields are not used, and the CommuniGate POP module "trusts" the addresses listed in the specified fields.
The included file "sendmail-UDWA.txt" is a sample update file for a Un*x sendmail configuration. It adds the X-Real-To header to messages stored in POP accounts. Send this file to your provider if they cannot reconfigure sendmail themselves.
ONLY WHEN A SPECIAL HEADER IS USED, AUTOMATIC MESSAGE DELIVERY IS GUARANTEED. If your provider does not store the envelope information with your messages, some messages will not be routed properly: they will go to the Postmaster, and the Postmaster will have to reroute them - manually or using the User Rules. For example, messages from mailing lists do not have any usable information in their To: and Cc: fields, so if no special header can be used, the CommuniGate POP module will route them to the Postmaster.
ONLY when a special header is used, you can use the CommuniGate Router to route the messages: without a special header, each address in the To: and Cc: field MUST be in the username@domainname form, where the domain name MUST be your own domain name, and the username MUST be a registered CommuniGate User name - not an alias, not an address on some other system.
CommuniGate POP as a POP Server. Remote Access.
You may want to enable access to the CommuniGate user mailboxes via Internet or your TCP/IP LAN. the The CommuniGate POP module can work as a POP3 server, so any regular E-mail software supporting the POP3 protocol over TCP/IP can be used to connect to your CommuniGate server and to retrieve mail from user mailboxes.
To enable the POP server, set the TCP Channels setting in the Serving POP Clients section to non-zero. This option limits the number of POP clients that can be served simultaneously over TCP/IP.
DO NOT SET the set the TCP Channels setting in the Serving POP Clients section if you have an individual dial-up link: the POP server is almost useless in such a configuration, but the server will try to keep your dial-up link up, ignoring the TCP Schedule restrictions.
The CommuniGate POP module supports POP client mailers that can employ AppleTalk (ADSP) protocol. To allow those POP mailer applications to connect to your server, set the AppleTalk Channels setting in the Serving POP Clients section to non-zero. Claris Emailer™ can be used as an AppleTalk POP mailer, if it is configured to use an "OfficeMail" account.
When AppleTalk access is enabled, the CommuniGate POP module registers itself on the AppleTalk as a service of type "RRPOP", and the CommuniGate Server domain name is used as the AppleTalk service name.
Providing Unified Domain Wide Accounts
You may want to use the CommuniGate POP server to provide Unified Domain-Wide accounts for your client systems. In order to store all mail for the domain xyz.com in the account ABC, you should:
• make sure that the DNS records direct the xyz.com mail to your CommuniGate server.
• register the CommuniGate user "ABC" with your server, and set the password for that user.
• add the following line to the CommuniGate Router:
xyz.com = <local>ABC
When a message is sent to localname@xyz.com (where localname is any address - simple or qualified), that message is stored in the ABC CommuniGate account. When that messages is being retrieved with a POP client, the CommuniGate POP module inserts the Special Header field into the message header. The header field format is:
X-Real-To: localname
Note that the X-Real-To header will contain only the localname. If you want to pass the "xyz.com" string as well (in case one domain-wide account is used for several domains), you should use 2 lines in the Router:
xyz.com = xyz.com%xyz-pop
xyz-pop = <local>ABC
The first line just adds a fictitious domain keeping the original one. The second one routes messages to the ABC account and removes that fictitious domain.
Installing the CommuniGate POP module
Place the CommuniGate POP module file into the Modules folder inside the CommuniGate Folder in your System Folder. Restart the CommuniGate Server computer.
If you use the FreePPP product as your link to the Internet, make sure that the TCP Agent application is placed into the Modules folder. That application can be found in the CommuniGate Server software archive.
Configuring
When the CommuniGate POP module is in the Modules folder on the Server computer, you can configure it from any workstation that has the "can configure" privilege.
1. Choose POP from the Monitor section of the Server menu. The POP Monitor window appears.
2. Choose Service Settings from the POP menu. The POP Service Settings dialog box appears.
3. Set the TCP/IP Channels option in the Poll External Hosts box. This option limits the number of simultaneous TCP/IP connections the CommuniGate POP can make to poll accounts on remote hosts. Usually, 1-3 is enough, you may increase that number if you have many users with many POP accounts on external hosts. The Use APOP option allows the CommuniGate POP module to encode passwords sent to a remote host (if that remote host supports this feature).
4. Your provider host can collect all mail for your own domain in one POP account. If you have such a "Unified account" on some host, fill the Unified Domain-Wode account settings. Put the account name into the Account field, the account password - into the Password field. The account name should be accountname@domain.name, where domain.name is the PROVIDER POP SERVER DOMAIN NAME, not your own domain name. Use the Check Every setting to specify how often the Unified account should be polled. If the provider system stores the message envelope information in a special message header field (see above), enter that field name in the Special Header field.
5. If you want to use POP mailers with your CommuniGate Server, configure the Serving POP Clients options. The TCP/IP Channels option limits the number of simultaneous incoming POP connections the CommuniGate POP module can accept. You should set a nonzero value if you want remote users to be able to connect to your CommuniGate server using any E-mail program that supports the POP3 protocol.
Note: You usually set this option to 0 if you use a personal dial-up link to the Internet, otherwise the CommuniGate POP module will reopen your dial-up link as soon as it is closed.
The CommuniGate POP can serve POP clients that use AppleTalk instead of the TCP/IP (as Claris Emailer™ in its "OfficeMail" mode). Specify non-zero AppleTalk channels if you plan to use POP mailers over your AppleTalk network. The CommuniGate POP registers itself on the AppleTalk as a service of "RRPOP" type, and the Communigate Server domain name is used as the service name. The AppleTalk service is avalable only for the CommuniGate Server using the OpenTransport networking.
6. If you have allowed the module to serve POP clients (see above), then you can set the default POP Access settings. Each user can override these options using the POP Access panel in his/her User Settings.
See the Using POP mailers to Access CommuniGate Accounts section below.
7. Set the Log level.
Note: if you select the All Info log level, log files will become very large very quickly and the system may operate slowly when a POP connection is active.
Setting Individual User Accounts
Each CommuniGate user may have one or several E-mail POP accounts on one or several external servers - even if there is a Unified Domain Wide account for the CommuniGate Server domain. Each user may want to make the CommuniGate Server poll those accounts periodically and retrieve all messages on the user behalf, so all mail directed to the user - either sent directly to the user's CommuniGate account, or sent to one of his/her old POP accounts on other hosts will be collected in the CommuniGate InBox.
To specify POP accounts to poll, a user should choose User Settings from the Edit menu and select POP Accounts in the list on the left side of the User Settings dialog box.
Each account should be entered as <username>@<host name>, for example: myaccount@that.host. The Check Every option allows you to specify how often that account should be checked. When the CommuniGate POP module connects to one of the specified accounts and detects new mail there, it downloads new messages and they appear in the usewr InBox.
When the CommuniGate Server does not have its own domain name and it cannot receive Internet E-mail for all its users (no uucp link, no smtp feeds, no unified POP-accounts), each user may want to select one of his or her accounts on foreign hosts as the "primary account", i.e. its account name should appear as the 'From:' address in all the messages posted by that user.
Let's say your account with the CommuniGate Server is John Smith, the CommuniGate Server domain is cGate.mycompany.com (i.e. not a real domain), and all your mail goes to the host mail.mycompany.com where you have an account jsmith@mail.mycompany.com.
You enter this account (jsmith@mail.mycompany.com) into the list of your POP accounts, so it is polled and mail from there appears in your (John Smith) CommuniGate In Box.
When you compose a message, the From: address generated is John_Smith@cGate.mycompany.com.
If you want jsmith@mail.mycompany.com to be your From: address, so all replies will go to your POP account, you should choose User Settings from the Edit menu, select the Personal Info panel, and enter jsmith@mail.mycompany.com into the Special 'From:' Address field.
Using POP mailers to Access CommuniGate accounts
When the CommuniGate POP module is installed, each CommuniGate user can enable remote access to his/her mailbox, so any POP-based E-mail program can be used to retrieve mail from the CommuniGate Server remotely. You may need this feature if you have to use POP mailers on your network: mailers like Eudora® or Claris Emailer® are POP-based, and they use the POP3 protocol to retrieve mail.
Note: if your name (as registered with the CommuniGate Server) contains spaces, use the underscore (_) symbols in place of the spaces when specifying your account name in a POP mailer: if you are registered as John Smith with the CommuniGate Server mycompany.com, then the account to be used with a POP mailer applications is John_Smith@mycompany.com.
Passwords
To enable POP access to your mailbox, choose User Settings from the Edit menu and select the Password panel.
When using POP mailers to access your In Box, you can use your MacOS password set with the Users&Groups panel on the CommuniGate Server computer, and you can specify an alternative password. If you do not access the CommuniGate Server via LAN, you may be not registered with the Users&Groups panel on the Server, so you should specify an alternative password. If you have a MacOS password set in the Users&Groups panel on the server computer, but you do not want to use that password when connecting with a POP client, disable the Use MacOS password option. If you disable that option and the alternative password field is empty, access to your InBox via the POP protocol is disabled.
Access Options
To specify the POP Access options, choose User Settings from the Edit menu and select the POP Access panel.
If you select the Use the POP module Defaults option, POP access to your CommuniGate Inbox is controlled with the Serving POP Clients settings of the CommuniGate POP module.
Usually E-mail applications retrieve mail using the POP protocol and mark the retrieved messages as deleted. You can specify what the system should do with those marked messages: it can either delete them, or it can just mark them as Read. If the Marked as Read option is selected, the marked messages are left in your In Box and they can be read with the CommuniGator and IMAP mailers, but they disappear for POP-based E-mail applications: the CommuniGate POP module shows only new, "unread" messages to remote POP clients. Please note that the read/unread markers a POP mailer displays have nothing to do with the read/unread status of the messages in the CommuniGate InBox.
The Require APOP Authentication option forces remote users to use the secure APOP method when sending passwords to your CommuniGate server.
Note: the APOP authentication method is available only for the passwords set with the Password panel: MacOS passwords (entered with the Users&Groups control panel) cannot be used with APOP.
Forced Polling
When the POP Monitor window is active in the CommuniGator application, selecting the Activate Service Now option forces the POP module to poll the Unified Domain Wide account and all User accounts immediately (if the number of TCP/IP Channels used for polling is big enough).
Troubleshooting
If you see that the CommuniGate POP module tries to poll an account on some host, but it fails, or it cannot negotiate with that host, switch the Log Level setting to Low-Level Info or All Info. After the next attempt, switch the log level back and examine the log. If you still cannot find the source of the problem, and the administrator of that host cannot help either, copy that part of the log and e-mail it to support@stalker.com with the detailed description of the problem as you see it. Include the information about the versions of your CommuniGate Server and CommuniGate POP (choose the About CommuniGate from the Apple menu in the CommuniGator application).
Revision History
2.5 24-Aug-97
• Serving POP clients via AppleTalk is implemented.
2.4 13-Jun-97
• The new STREAMS kernel manager is used for all communications.
• The new "unconditional" priority is used for incoming connections (important if the server also runs a dial-up IP gateway).
• The "200 visible messages per mailbox" limitation is removed.
2.3.1 16-May-97
• Module name changed to POP
• The new Apple technique is used to avoid the situation when the CommuniGate POP server becomes "deaf".
• The balloon help is implemented for the Service Settings dialog box.
2.3 05-May-97
•The UIDL command (used by Netscape and other mailers) is implemented.
• The secure APOP authentication mechanism for outgoing connection is implemented.
• The secure APOP authentication mechanism for incoming connections from POP clients is supported.
• The new communication services of the CommuniGate Server 2.9 are employed.
• The time of the last connection to the Unified POP account is shown in the Service Settings dialog box.
2.2 28-Feb-97
• If polling a remote POP account fails, the next retry will be made in 3, not one minutes. This allows a PPP link to time-out.
• Password is removed from the POP Access panel in the User Settings: a separate Password panel is used now.
• TCP Scheduling is supported for dial-up lines now.
