BIWINE@VAXSAR.VASSAR.EDU (Bill Wine) (01/09/91)
Last month I asked the net if the POP3 protocol was appropriate for a large Mac/PC mail system. I received some replies to that question, but I received even more requests such as "if you get some good answers, please let me know, since we are looking for a mail system, too". For that reason, I thought it might be useful to present some basic information that I have gathered over the last 2 months about public domain Mac-based mail systems. I do not claim to be an expert on this topic. First, I am aware of 3 pd mail management protocols for which client-server software is available. These are POP2, POP3, and IMAP2. The protocol descriptions are available via anonymous ftp from nic.ddn.mil. cd to RFC:, first. POP2 is described in RFC937 (dated 2/85), POP3 in RFC1081 (11/88), and IMAP2 in RFC1176 (8/90). For information on what software is available and where to obtain it, I suggest an excellent article by Mike Liveright which can be found in the info-mac digest. Ftp to sumex-aim.stanford.edu, and get info-mac/digest/infomacv8-145.txt. The following is a summary of the pd mail systems I reviewed: 1. MacMS is an IMAP2 client. The mail is stored on the host. This means that you can read all of your mail no matter where you are. You could use a Mac client, a PC, Unix workstation or terminal. Also, the backup is done on the host, so the user is less likely to lose mail. The client remains logged into the host (1 host process per client). A check for newmail is done at a user-defined time interval. There is an excellent message selection feature - search on RFC header (from, subject, date, etc.) and/or body text. Also, an easy to use mail reader (close current message and open next). You can move selected messages from the current mailbox to another, but only 1 mailbox may be open at a time. I did not see a feature to append a file to a mail message. User preferences are set in a startup document. A PC client is available or will be soon. 2. TechMail is a POP3 client. Mail is transferred from the inbox on the host to the client, and deleted on the host (no option to save mail on host). You can have multiple mailboxes on the client, and transfer mail among them. More than 1 mailbox may be open at the same time. User preferences are easily set in the program. There is a built-in finger and directory. The client does not remain connected to the host. The client connects to the server, gets newmail, and disconnects. The main drawback to this product is that there is no automatic notification of newmail. The user must initiate this. I understand that newmail notification or automatic check will be provided in the next release. There is a discussion list with an archive. Text files may be sent with mail. No PC client. 3. Eudora is also a POP3 client, and it is similar in function to TechMail. One important difference is that Eudora checks for newmail by connecting to the host at a user-defined time interval. Setting the time to zero turns off the check. Also, Eudora gives the option of saving mail on the host after it is transferred to the client. This can be an important backup feature if the server is modified to move mail to an archive folder, or distinguish between old mail and new mail. Eudora supports enclosures of any file type (automatic binhex conversion). Supports multiple mailboxes on the client and can sort messages based on sender, subject or date. It also sends commands to a nameserver and gets back the results. No PC client. 4. HyperMail is a POP3 client. Unlike the 2 POP3 clients described above, it remains connected to the server, and mail remains on the host. It sees only the inbox folder on the host. Messages may be saved as individual files on the client. 5. MacPOP is a POP2 client which requires an enhanced POP2 server. I did not check out the difference, but it did not work with a regular POP2 server. The client remains connected to the host, and the mail remains on the host. Only the inbox on the host can be seen. The POP2 protocol does provide a folder command to select a different mailbox on the host, but this product does not seem to use that feature. One message at a time can be saved to an individual text file on the client. The interesting thing about MacPOP is that it uses an auxilliary program, POPAlert to provide notification of newmail. POPAlert is an init/cdev which listens on a DDP port. The package includes a modified comsat program that sends a DDP packet to the client Mac when newmail arrives. MacPOP polls a driver to discover the arrival of the DDP packet, and then automatically downloads the newmail from the host. The comsat program looks for a file in the login directory which contains the zone(s) in which the user's Mac is likely to be found. This works in a fairly static environment. There is also a PC version which works in a similar way (sends a UDP packet), but I did not try it. I have seen suggestions in the Techmail interest group mailing list that POPAlert and the modified comsat program could be used to provide asynchronous newmail notification for Techmail until the next release. This would notify the user with an alert, and the user could then opt to get the newmail from the host. Others may argue that it is too difficult (or not worth the trouble) to provide reliable asynchronous newmail notification in a non-static mixed client environment. The cost (in terms of cpu time) for a POP3 client to connect to a host and check for newmail is very low (with a fast server, less than 1 second of cpu time). On the other hand, the commercial mail systems do provide pop-up notification. 6. POPMail is a POP2 client Hypercard implementation. It does not remain connected to the server, and uses an auxiliary program (Nag) to notify the client when newmail arrives. Nag polls the host at a pre-determined interval. It does not support multiple mailboxes. Messages can be saved on the client as individual files, or in a stack archive. I did not spend a lot of time looking at the 2 Hypercard implementations. 7. MacPost uses a proprietary protocol, and is the only pd system I looked at that does not require MacTCP on the client. It's architecture seems closer to the commercial mail systems, such as QuickMail. The client Mac communicates with a dedicated server Mac, which communicates with an SMTP host. Newmail notification is provided. Multiple mailboxes are not supported. Text file enclosures only. Client must be registered with the server. There is an interest group mailing list. The most important step in choosing a Mac-based mail system is deciding on the underlying architecture. Do you want the mail to remain on the server, or should it be transferred to the client? Other questions: Do you need to support PC's as well as Macs? Will you support MacTCP or PC/IP on each client? Does the implementation support multiple mailboxes and enclosures? Is it generally easy to use? Is your server well matched to the number of clients? One feature that I did not see in any client is automatic filing of messages into mailboxes based on user-defined rules (as in some Unix systems). This would be nice on systems that transfer mail to the client. I hope that this article has been useful to readers looking for a Mac- based mail system. I have generally avoided references to ftp sites. See the info-mac digest article noted above for that information. The information presented here is based on my use of the software, and it is not guaranteed to be correct. Bill Wine biwine@vassar.edu