Exchange Server

Richard · Guest

Now that SMTP is the default protocol for Exchange 2000/2003, are
there any advantages in having dedicated SMTP "bridgehead" servers for
routing inbound/outbound Internet mail?

The proposed design is a pretty typical architecture including a
4-node Active/Passive Exchange 2003 Cluster. An ISA server acts as an
SMTP smart host in the DMZ.

All messages are virus checked and filtered for SPAM.

Theoretically, all of the backend Exchange servers can send outbound
SMTP mail directly to the SMTP smart host (in this case, ISA Server).
Inbound mail can also be directly routed to the backend Exchange
servers. Are there any advantages of having SMTP mail relayed to the
Exchange "bridgehead" servers before being routed to the smart host?

I can think of some potential advantages for having two (redundant)
dedicated bridgehead servers:

1. Message Tracking Logs are centralised. An administrator can more
easily track messages in a large messaging environment as they will
know which Exchange server (bridgehead server) to connect to every
time.

2. Having dedicated SMTP bridgehead servers increases service uptimes
on the backend Exchange servers. For example, lets say a third party
application requires a dedicated mail relay to be hosted on Exchange.
This may require the SMTP virtual server to be restarted on the
dedicated bridgehead server. This would have caused interruptions to
services on the backend servers.

3. Having dedicated SMTP bridgehead servers lessons the performance
impact on the backend servers. For example, let's say a custom
in-house application creates 20,000 customer services email per day
and this requires the use of a mail relay on Exchange. If the backend
Exchange servers were used as the mail relay, this could cause a
performance impact. Having the bridgehead SMTP servers perform this
role lessons the impact on the backend servers.

Disadvantages:

1. Extra cost for dedicated servers.
2. Increased administration.

The concept of an SMTP bridgehead servers dates back to Exchange 5.5
and I havn't heard Microsoft recommending this need since Exchange 2K.
I would be really interested in hearing people's
opinions/recommendations.

Regards,
Rich.

Jim Schwartz · Guest

In my opinion you pretty much hit the nail on the head. In addition to #3
you can better plan capacity in a larger environment as you can scale up the
front end servers without having to worry about the user impact.

You can also put AV on the front end servers that is different from the one
the mailbox servers for defense in depth.

"Richard" <richard_mart@hotmail.com> wrote in message
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