An individual can intentionally or inadvertently overwhelm your mail server by flooding it with messages. This type of act is called a denial of service attack. If a denial of service attack is perpetrated against your mail server, either there may be a substantial impact to the throughput of your mail server or your mail server will become overloaded and nonfunctional.
SIMS provides features that enable you to minimize the possibility of a denial of service attack and well as help you control spam (unwanted or unsolicited email):
|
|
Email access restrictions - Enables you to specify which incoming messages are accepted or denied based on recipient or originating domain, client IP address, server IP address, or originating email address. (See "SMTP Access and Relay Restrictions" on page 106). |
|
|
Message size limits - Enables you impose a limit at which a message is deemed too large and rejected by a channel. (See "Message Limitation" on page 125.) |