MILTER_NO_NAGLE
Turn off Nagle algorithm with Milters Tune with confENVDEF
Named for its creator, John Nagle, the Nagle algorithm
is used to automatically concatenate a number of
small network messages together and then transmit
them together. This process (called nagling)
increases the efficiency of a network application
system by decreasing the total number of packets
that must be sent for the same data. The Nagle
algorithm is sometimes considered undesirable for
use in interactive environments, such as with some
client/server situations like sendmail-to-Milter
communications. In such cases, nagling may be turned
off by defining the TCP_NODELAY sockets option.
If you wish to turn off nagling for sendmail’s communication with its Milters, you may do so by defining the following, and then rebuilding sendmail:
APPENDDEF(`conf_sendmail_ENVDEF', `-DMILTER_NO_NAGLE=1')
By default, nagling is turned on for communication with Milters because turning it off does not improve performance on all operating systems.
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