When you are securing a system that allows access from another domain, you must consider both internal and external security.
External Security
External security involves administration to prevent access from an unauthorized source. These sources can include a subscriber who is administered to use email or remote AMIS analog networking. Users might send "mail bombs" to an enhanced-list. Mail bombs are harassing messages that not only do not serve your business needs, but also impose unnecessary traffic on your system.
ELA mailboxes are no more vulnerable to unauthorized use than are any other voice mailboxes. However, the impact on system performance can be many times greater.
To prevent unauthorized access to an ELA mailbox from an external source such as email users or remote AMIS Analog networking users, you can place those subscribers in a community with sending restrictions.
Internal Security
Internal security focuses on preventing or recovering from damage if a breach occurs, for example, if a virus is transmitted in a message component such as an attached software file.
Communication Manager Messaging allows for the transmission of two message components, text (originating from Message Manager or email) and binary file attachments (software files, such as a spreadsheet or word-processing file). With these components come related security considerations, namely, the inadvertent delivery of a computer virus that could be embedded in a file attachment. This problem can occur in any system that supports the delivery of software files. While the Messaging server cannot be infected with viruses embedded in these software files, client machines can become infected when a user launches the application associated with the software file.
Note ELA does not perform any virus detection. The customer needs to evaluate the security risks of file attachments carefully and make provisions for virus detection software on PCs running Message Manager or an email application supported by Communication Manager Messaging.
At a minimum, advise your users to detach (that is, not launch) file attachments and scan them for viruses before use.