SMTP Traffic Throttling identifies IP addresses or sender addresses that deliver connection
requests or email messages too frequently and blocks these addresses if they trigger
specific
rules. You can customize IP-based and sender-based throttling rules to monitor behaviors
of
all IP addresses and senders and take actions on them if necessary. The rule criteria
include
the duration to monitor, maximum number of connections or messages allowed, and block
duration. The difference is that sender-based throttling does not allow you to specify
the
maximum number of connections while IP-based throttling does.
The following process takes place after IMSVA receives a
connection request from a sending mail server or a sender:
-
SMTP Traffic Throttling records the number of connections from this IP address in the specified duration to monitor.
-
SMTP Traffic Throttling records the number of email messages from this IP address in the specified duration to monitor.
-
SMTP Traffic Throttling records the number of email messages from this sender in the specified duration to monitor.
-
When the number of connections or messages from this IP address reaches the threshold you set, SMTP Traffic Throttling will add this IP address to the Blocked List and block subsequent connections or messages from this IP address temporarily.
-
When the number of messages from this sender reaches the threshold you set, SMTP Traffic Throttling will add this sender to the Blocked List and block subsequent messages from this sender temporarily.