Overview
The Mail Fetcher functionality allows mail from a remote POP3 mailbox
to be loaded into the Sambar Mail Server for later retrieval (via POP3
or WebMail).
The Mail Fetcher is designed to give users with "part time"
connections to the Internet or users without stable 7/24 full-time
connection suitable for running a mail server. The following
outlines how the Mail Fetcher might be used:
- You have a single ISP mailbox, e.g. "tod"
- You have a domain name "sambar.com" and your ISP routes
all mail to the "sambar.com" domain to the account "tod".
(This feature is often setup by default.) So mail sent to
"support@sambar.com" is deposited in the mailbox "tod".
Assuming you have setup local users/mailboxes for tod,
support and other, with the above configuration,
you would setup a Mail Fetcher as follows:
- Retrieve mail from the remote mailbox "tod"
- Configure the Fetcher to accept mail for the
Local Domains "*sambar.com".
- Configure the Unknown Mailbox for the fetcher as other
When the fetcher runs, all mail to tod@sambar.com is delivered
to the local mailbox tod, mail to support@sambar.com
is delivered to the local mailbox support, and mail
for any other sambar.com account is placed in the other mailbox.
Fetcher Routing
There are three routing options for mail retrieved via the fetcher.
- unknown Route all mail to the specified unknown mailbox.
This is the most reliable fetcher option as all it does is retrieve
the mail and place it in a single mailbox.
- local or all Route all local mail addresses
discovered in the To: and Cc: mail headers. If no
local address is found, the mail is placed in the Unknown mailbox.
- full Route all mail addresses found in the To: and
Cc: mail headers. In general, this option is not advised
for regular use (it is a special mail relay feature); looping of mail
can result.
Operation
When the Fetcher retrieves mail, there are two modes that can be used:
- Put all mail from the remote mailbox into a specific local account.
- Try to route mail to all the local address found in the
To: and Cc: mail headers.
If the second option is used for the Fetcher, the Local Domains
of both the [smtpd] section and fetcher configuration are used to
determine if the user has a "local" account.
Important! The fetcher will be automatically disabled if the
POP3 server mail is being retrieved from fails 10 successive times.
Note: This can be configured in the config/mail.ini
by modifying the Maximum Fetcher Failures parameter.
In the event a fetcher is disabled, mail will be sent to the
Unknown Mailbox account notifying the user of the failure
(if an unknown mailbox is configured).
Fetcher Aliases
A special aliases section of the mail.ini applies only to
the fetcher to accomodate mail delivered to mailing lists (where
no recipient is identified). For example, mail received from a
mailing list often has the same To and From address
(such as sambarlist@skyweb.se). Because no local user is associated
with this address, the fetcher would deliver the mail to the
Unknown Mailbox. You would not want to setup a standard alias
for this because this would prevent you from responding to the
mail message (outgoing mail would also be directed to aliased local account).
To accomodate these situations, the fetcher-aliases can be
configured to apply aliases to only fetcher retrieval. These
aliases function just like regular mail aliases, except they only apply
to mail delivered via the fetcher.
|