beautypg.com

PLANET CS-2000 User Manual

Page 350

background image

CS-2000 UTM Content Security Gateway User’s Manual

- 344 -

Mail Transferring Process

The 3 elements of the e-mail send / retrieve:MUA, MTA, MDA.

„

MUA ( Mail User Agent )

The client PC needs to use the MUA provided by the OS to process

send / retrieve. For example, the outlook express is a kind of MUA. The MUA can receive or

send the mails via the mail server, and also provide the user to read and edit mails.

„

MTA ( Mail Transfer Agent )

User need to use MTA to send / retrieve the mails. The MTA

includes 3 functions :

1.

To retrieve the mails from external mail server:The MTA will receive the mails from the

external mail server, when the recipient mail account existed in the MTA.

2.

To help user to send the mails:When the user has the authority to use the MTA, then he can

send the mails via MTA.

3.

To let the user can receive his own mails:User can receive his own mails from the mail

server.

The mail server is a kind of MTA.

„

MDA ( Mail Delivery Agent )

The MDA can deliver the mails to destination local user’s

mailbox from the MTA, or send the mails from the current MTA to next MTA.