[Mimedefang] Semi OT: Best configuration for two servers to handle > 20,000 msgs/day

[Nels Lindquist]

On 3 May 2004 at 15:30, Shayne Hardesty wrote:

<snip>

>    1) New server becomes primary MX, has sendmail, mimedefang, 
> spamassassin, and uvscan.  Any incoming email gets scanned by new server 
> then handed off to current server (via SMTP) for storage.
>    Pros: Easy configuration/setup/management, somewhat scalable (just 
> add more primary servers)
>    Cons: Does not scan user to user (inter-company) email.  Does not 
> scan outbound email, unless current mail server is reconfigured to pass 
> email to new server, or user clients are reconfigured to use new server 
> as outgoing smtp server.  Does not handle unknown users in SMTP session 
> unless virtusertable is maintained from SQL database via perl scripts, 
> or LDAP.  Hard to use graphdefang - must collect stats from two 
> different maillogs.

I'd suggest a modification of scenario 1 in order to overcome some of 
the potential drawbacks.  If you were to switch from the UW IMAPD to 
Cyrus IMAPD 2.2.x, you could take advantage of a remote socketmap 
daemon for dynamic local user checking and use remote LMTP for 
delivery, which should be more efficent than SMTP.

All SMTP traffic would go through your new primary server.  Your old 
box would become a dedicated mailstore, handling all the web, POP3 
and IMAP traffic.  It could be renamed or, alternatively, you could 
port redirect with a router or directly on the new server to avoid 
client re-configuration.  You'd incur some extra overhead, but 
certainly far less than having to kluge a mailstore over NFS.

Other advantages: 
o local /etc/passwd accounts not required - better security
o SASL authentication store can be SQL - easier administration
o Cyrus supports a lot more features than UW IMAPD
o Far more scalable - Cyrus murder IMAP aggregator can be used for 
load distribution

Cons:
o Transferring mail to new server can be a headache
o Significant added complexity for initial setup

----
Nels Lindquist <*>
Information Systems Manager
Morningstar Air Express Inc.