Smart Setup Systems 1. DNS machine

We will need our own authoritative DNS server for the hosted domains to speed up DNS queries inside the infrastructure. This machine will serve to the mail servers involved in the setup, as well as to some mail service related requirements. It is recommended that this DNS server would be run as a caching server also, with the positive TTL for queries to be fairly large and the negative TTL to be small, since many DNS queries can return negative responses due to high loads caused by spam.

This server can also run a DNS local blacklist, which is faster than the public ones, and is also in control of the setup's administrator.

2. The mail infrastructure front-end machine

This machine will perform the task of running the mail server that receives all incoming connections and will consist in the largest part of the DNS traffic since it will be responsible with the initial checks of the incoming connections. The task of this machine will mainly consist in being able to manage all incoming connections and perform the DNS checking phase of the remote hosts.

After a connection is accepted, the mail server will only perform the routing of the message to the next machine that will perform the next checking phase of the message.

3. The message analyzing machine

Depending on the volume of messages, the role of this machine can be divided and distributed to two machines. The purpose of this machine will be to perform AV and AS scanning of messages received from the front-end.

If the two machine situation is required, the AV part can be handled by one machine, since the hardware load for the AV scanning process is lower than the one for the AS scanning process, and it may be required, although optional, to use more AV scanning products to process the message. The AS scanning machine can be organized similar to the AV scanning machine.

4. The back-end machine

This machine will actually store and manage all domain accounts, preferences and messages. Just like in the previous example, of the scanning machines, more machines can be used to store user accounts in this case too. This machine will only receive the already processed messages and deliver them to the intended recipient's mailbox.

This machine will also take care of the sending process for the stored users.

5. The sending machine (optional)

If required, a final machine can be introduced in this design, to take care of processing the messages before they leave the mail infrastructure; some companies desire to scan the outgoing messages too, so a separate machine that will perform scanning of the messages before they are sent may be required to relieve the back-ends of this time consuming operation.