Hello everybody.

The following giagram describes how the two mail servers processes POP
load balancing of Courier-IMAP(3.0.8).

--------------------------------------------------------------------
       |            |                  |
    Load balancer(CSS)     OpenLDAP Server        Client
     |   |
  MailSpoolA    MailSpoolB
   |       |
   |       |
    ------NFS-------

To explain the flow of the data, first, client establishes POP connection
to the virtual address of  loadbalancer to retreaves their email.

The loadbalancer uses "round robin" method, which decision relise on
the sender's IP addresses.

Nornally, this works with no issues, however, on OutLookExpress(6) with
"make copy of email on server" option enabled, within 2-5 days later,
clients are receiving same email that they've already received in past 2-5
days.

Folowing is the result of IMAP's UIDL command:

***********************************************************
■MailSpoolA
[EMAIL PROTECTED] root]# telnet localhost 110
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
+OK Hello there.
user [EMAIL PROTECTED]
+OK Password required.
pass *****
+OK logged in.
list
+OK POP3 clients that break here, they violate STD53.
1 11120
2 11370
3 1328
.
uidl
+OK
1 1196222123.16414.pop02.example.com,S=10855
2 1196248456.26392.pop03.example.com,S=11101
3 1196248477.26870.pop02.example.com,S=1299
.
■MailSpoolB
[EMAIL PROTECTED] root]# telnet localhost 110
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
+OK Hello there.
user [EMAIL PROTECTED]
+OK Password required.
pass *****
+OK logged in.
list
+OK POP3 clients that break here, they violate STD53.
1 11120
2 11370
3 1328
.
uidl
+OK
1 UID147-1195179386
2 UID148-1195179386
3 UID149-1195179386
.
***********************************************************

The values presented with UIDL command does not matches to one another.
Can you tell us which value is correct, and are there any suggesion on
how to avoid this issue from being occuring?

■System implemented with:
RedHat ES 4(U4)
Courier-IMAP 3.0.8
qmail-1.03

Thank you for your time to look in to this issue.





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