
- High Volume
- Virus Package Choice
- Multi Platform
- Flexible
- Distributed
- Extensible to Other Applications
Virus Checking at the Boundary
Enterprises should be providing anti-virus protection in two places.
The first place, which is the primary target of most anti-virus solutions,
is on the desktop. Desktop protection, both for individuals and staff
within enterprises, is an important protection point, as this is where
viruses generally attack.
M-Switch offers complementary protection to desktop checking, by examining
email messages as they come in and go out of an organization or service
provider.
How does boundary checking work?
A boundary email anti-virus solution has two components.
- The software that checks for viruses. This is a specialist anti-virus
component that is not provided by Isode. Isode provides options to
work with commercial packages from Norman
or Sophos,
and from the free (Unix) ClamAV
package. Support for other anti-virus packages is generally straightforward
to add.
- The software that handles the email, and controls which email is
checked and how the overall process is managed at the email level.
This is the capability provided by M-Switch.

Boundary Messaging to provide anti-virus
What does M-Switch do to support Anti-Virus checking?
The basic function of M-Switch to handle viruses is very simple. It
takes an inbound stream of SMTP messages, separates out the message
content to hand to a virus checker, and then sends clean messages onward
by SMTP. M-Switch can be easily inserted into an SMTP message stream,
to add anti-virus capability. The more detailed process is:
- M-Switch has the concept of "channels" which perform specific functions
on messages in the internal queue. There is a core anti-virus channel,
which M-Switch uses to perform virus checking. This is programmable,
so it may be invoked (by the same instance of M-Switch) with different
parameters in different situation, or even with different virus checkers.
- M-Switch can be configured to invoke the anti-virus channel on
all messages, or on selected messages (e.g., "all inbound", "all outbound",
"all messages from organization X", "all messages to user X".
- M-Switch can control virus checking by size. In particular, virus
checking can be skipped for very small messages (which are common
and will be too small to carry a virus).
- The virus checking channel can do various things on detecting a
virus, including one or more of:
- sending a customizable message back to the sender
- sending a customizable message on to the intended recipient
(example below)
- removing the infected body part, and then replacing it with
another body part (typically one that says "there was a virus
infected thing here")
- if the virus checker can clean up the virus, the channel can
replace the infected body part with a clean one
- The virus channel logs all activity, which can be processed into
management reports as needed.
- The virus channel has a framework, which can be used with any virus
checker that provides an API or command line interface. Integration
is straightforward. While the virus checker is usually run on the
same machine as the message switch, it can also be set up to run remotely.

Why M-Switch Anti-Virus?
High Volume
M-Switch is a high volume message switching product used by large
organizations around the world, that provides strong management capabilities,
and flexible integration of value added processing. This makes is
an ideal base for controlling anti-virus processing.
Virus Package Choice
M-Switch can be used with your choice of anti-virus package or packages
(we recommend Sophos if you do not have a preference). Boundary checking
should, to gain maximum security, use a different package to the one
deployed on the desktop (Anti-virus companies generally fail to make
this important recommendation)
Unix as well as Windows
M-Switch can be used for anti-virus checking on Linux, Solaris or
Windows 2000 Server (many of the alternatives are Windows only).
Warnings
Warning email messages: M-Switch can deal with virus infected messages
automatically, sending warning messages both to sender and intended
recipient, according to enterprise policy. More details on this process
and configuration options are on www.isode.com
Flexible
M-Switch has a highly flexible configuration, allowing for example
checking of outbound messages, checking procedures to vary according
to message recipient.
Rock Solid
M-Switch has exceptional robustness and stability, including support
for fail-over clustering and Off
Site Hot Standby (Disaster Recovery).
Distributed
M-Switch can be deployed in a distributed manner, at one or more
locations, sharing a single configuration.
Policy Control
M-Switch provides a basic boundary message policy framework, which
can control the flow of messages in and out of the enterprise (e.g.,
to restrict who can send messages externally; to limit access to internal
addresses and lists; to distribute messages to multiple internal mail
servers).
Extensible to other applications
M-Switch can apply value added boundary processing in addition to
anti-virus, such as address rewriting, message archiving, and anti-SPAM
controls. By using M-Switch, you get a broad framework for managing
boundary messaging, as well as dealing with anti-virus.
Supported Platforms
M-Switch Anti-Virus is available on Solaris, Windows, Linux and HP-UX. More
details on supported platforms and versions can be found here.
When choosing platform, care should be taken to ensure that the chosen
virus checking package is available for that platform. In particular,
some packages are not available on 64bit platforms.