sendmail, 4th Edition

ConnectionRateWindowSize

Window of time in which to measure connection rates V8.13 and later

Under V8.13, two new sendmail macros, called ${client_rate} (${client_rate} on page 814) and ${total_rate} (${total_rate} on page 847), are available to control the number of simultaneous connections allowed. They are used by the corresponding new FEATURE(ratecontrol) (FEATURE(conncontrol) on page 619) and FEATURE(conncontrol) (FEATURE(ratecontrol) on page 638), which perform the same functions via the access database.

This new ConnectionRateWindowSize option sets the size of the window of time that is used to measure these rates. It is declared like this:

O ConnectionRateWindowSize = secs                 ← configuration file (V8.13 and
later)
-O ConnectionRateWindowSize = secs                ← command line (V8.13 and later)
define(`confCONNECTION_RATE_WINDOW_SIZE', `secs') ← mc configuration (V8.13 and
later)

Here, secs is of type time. If this option is omitted, the default for the window of time is 60 seconds. If this option is defined, but the time units are omitted, the default units are seconds.

We recommend you change the default only if you have not already made connection-limiting entries in your access database. If you make those entries first, and then later change this setting, you will silently change the meaning of those access database entries.

The ConnectionRateWindowSize option is not safe. If specified from the command line, it can cause sendmail to relinquish its special privileges.