Few Questions about Postfix.

Hi group,

I'm thinking about moving from MS Exchange mail server to Postfix, but I
need to know a few things before.
Because all my users have got McAfee AV running on their Windows machines I
think that I can runnaway from Microsoft insecutity (I'm talking about
Windows mail server) because users are locally protected.
Last week the mail server (Windows 2000 Advanced Server) was infected by a
vírus and it stops running, that's why I want to move for Linux, because
mail is essencial for the company business.
I'm new at the job, so I have to make some decisions.
I've got good underground with Linux and Postfix either, but I don't want my
users asking for functionalities that they had with Exchange.
For example:
Is it possible to make an autoreply when a user goes for hollidays?
Can you enumerate a few pros and conns?

Beste regards,

Nuno Paquete.

On 2004-12-31 09:24:47 -0500, "Nuno Paquete" <nmp@ispgaya.pt> said:

> Hi group,
>
> I'm thinking about moving from MS Exchange mail server to Postfix, but
> I need to know a few things before.
> Because all my users have got McAfee AV running on their Windows
> machines I think that I can runnaway from Microsoft insecutity (I'm
> talking about Windows mail server) because users are locally protected.
> Last week the mail server (Windows 2000 Advanced Server) was infected
> by a mail is essencial for the company business.
> I'm new at the job, so I have to make some decisions.
> I've got good underground with Linux and Postfix either, but I don't
> want my users asking for functionalities that they had with Exchange.
> For example:
> Is it possible to make an autoreply when a user goes for hollidays?
> Can you enumerate a few pros and conns?
>

Postfix by itself won't allow for clients to retrieve mail; you'll need
an IMAP or POP3 server for that. Keep that in mind as you make
comparisons between Exchange and a solution that includes Postfix.

Exchange offers a number of collaborative functions (group scheduling,
task assignments, etc.) as well as the "out of office" functionality
you mentioned. I'm sure that these functions can be recreated with a
"best of breed" mix of open source solutions, although I will be the
first to admit that I don't know which solutions to suggest nor can I
comment on the difficulty (or lack thereof) of integrating these
various separate pieces.

If you are concerned about the security of Exchange server, there are a
number of steps you can take to protect yourself without chunking
Exchange entirely:

1. Place a Postfix-based mail relay to handle all inbound and outbound
Internet e-mail. This isolates the Exchange server from the Internet
(no direct e-mail connections between the Exchange server and the
Internet). You can add ClamAV (an open source virus engine) to provide
another level of protection, as well as block executable attachments at
the Postfix relay before they hit your Exchange server. You can also
add SpamAssassin for improved anti-spam functionality as well.

2. Place an Apache-based reverse proxy server to protect all inbound
HTTP traffic (for Outlook Web Access). Using mod_security, mod_ssl,
and mod_proxy, you can offload all SSL processing to the Apache reverse
proxy (saving CPU load on your Exchange server) as well as block
potentially damaging attacks (think Code Red and Nimda) before they
ever reach the Exchange server.

With regards to e-mail, the real security risk is on the desktop (in
Outlook) not on the Exchange server, IMHO. That is where you have to
worry about web bugs, HTML script exploits, ActiveX controls in HTML
messages, VBScript attachments, etc. Of course, that's just my
personal position.

HTH.

--
Scott Lowe