15. WebMail Overview | (System Settings) |
This section describes how WebMail works. Please refer to the illustration at right.
WebMail Overview
You need to have a mail server (with email server software) other than the mail server where WebMail is installed. (See Note 1)
The mail server should comply with the standard email protocol, SMTP/POP3.
Clients will access the server machine where WebMail is installed with the browser. WebMail will serve as a mailer and communicate with the server machine.
To exchange mails both inside and outside of a department or company, the mail server should be properly set to execute these actions.
Note 1 The server machine where WebMail is installed and the mail server can reside on the same machine. In other words, both WebMail and the mail server can be installed on one machine.
The process for receiving email
This section describes the mechanism for receiving emails. A mail server in this section means a POP3 server.
- Mails sent from the outside will be delivered to the mail server and saved there temporarily. This is a function of the mail server, and at this stage WebMail is not involved.
- A client will open WebMail and communicate with the mail server to check if it has current emails. For example, Mr. A will use a client PC, open a browser, and log in "Cybozu Office 4". And using his POP3 server account (set at User Setting in WebMail) he can access the mail server and check if emails were sent. If they were sent, "You have --- new mails" will be displayed on the Portal Page.
- WebMail users may receive new email by opening WebMail from a client PC; the email will be delivered from the mail server. The received email will be saved in the server where WebMail is installed. Unless you set "Save Emails at POP3 server", emails on the mail server will be deleted.
At this time, WebMail does not support HTML mail with graphics.
The process for sending email
When you send email, the process is the exact opposite of receiving email. Email sent by WebMail will be delivered to the SMTP server. Normally, the SMTP server is functioning the same as the POP3 server. Copies of sent email will be saved in the "Sent" box in WebMail.
Limitations in sending/receiving email
WebMail does not comply with the following servers.
- A mail server that authenticates users only with the APOP or AUTH command
- A mail server that requires a POP authentication before sending
- A mail server that receives emails using a port number other than port number 25
- A mail server that receives emails using a port number other than port number 110
Hard Disk Space Used for WebMail
With WebMail, all received emails are saved on a server machine, and substantial hard disk space may be used. A minimum guideline is 1 Mbytes x numbers of WebMail users. For example, if 50 users use WebMail, a minimum of 50 Mbytes will be used.
If one user sends/receives 10 text-based mails per day, a total of 2 Mbytes of hard disk space will be used per month. For emails with attachments, it depends on the size of the attached files. For example, if 10 mails with a 1 Mbyte attachment each are received each day, it will total 10 Mbytes. Sent/received emails will be saved in the user's database.
Therefore, please carefully monitor how much hard disk is being used. Also, advise other users to frequently delete their sent/received emails.
You can pre-set total size of email to be saved per user in WebMail.
WebMail Speed
The operational speed of WebMail heavily depends on the transmission speed between WebMail and the mail server.
If many emails with attachments are exchanged, the transmission volume between WebMail and the mail server will grow substantially. As a result, the transmission speed will slow down tremendously.
If you expect that the transmission volume will increase substantially, we recommend that you use a high performance server machine and high speed network circuits. For example, if you use WebMail for 50 users, we recommend that you use a server machine with CPU Pentium III, memory 128MB or more, and high speed HD (Dell PowerEdge, Gateway 2000 ALR series, etc.) and install a high speed circuit of 100Mbps or more. For server OS, we recommend Windows NT/2000 or UNIX.
WebMail can be set to limit an email size. With this feature, you can block emails with large attachments.
WebMail is located inside the intranet, but the mail server may be outside the Intranet (on the Internet side). In this instance, the transmission speed between these two will be slower, and the operation speed may be delayed.