POP/IMAP before SMTP

[Lai Yiu Fai <ccyflai@ust.hk>]

Hi all,

Has anyone implemented POP/IMAP before IMAP with ZMailer smtpserver using the
policy filtering?  How it works:  everytime someone successfully enters a 
correct userid/passwd to POP/IMAP server,  the IP address of remote client
is logged in a .db file together with a timestamp.   The database will then 
serve as a list of IP addresses that are allowed to perform an SMTP relay by
the smtpserver.   A background process is used to expire addresses from
the database as their validity runs out, say 15mins.

Will it possible for smtpserver to reread smtp-policy database file without
any racing problem for frequent modification, say per 30 second?

Is anyone actual implementing such for avoid anonymous mail submission?

Rgds,
=======================================================================
Lai Yiu Fai                       |  Tel.:       (852) 2358-6202
Centre of Computing Services      |  Fax.:       (852) 2358-0967
 & Telecommunications             |  E-mail:     ccyflai@ust.hk
                                  |
The Hong Kong University of       |  Clear Water Bay,
Science & Technology              |  Kowloon, Hong Kong.