Provided by: opensmtpd-extras_5.7.1-1build1_amd64
filter-pause — smtpd filter to pause on new connections
filter-pause [-s seconds]
filter-pause is a filter for smtpd(8) which can be used to pause on new connections before emitting the standard initial SMTP greeting. This is useful to avoid the so called “slamming” technique used by some senders of spam mails. The options are as follows: -s seconds Set the number of seconds to pause before sending the initial greeting. The accepted values are withing the range of 1s and 300s. The default seconds value is 5s. With filter-pause enabled, smtpd simply waits the specified amount of seconds on each new connection. If the remote server starts sending SMTP commands before the greeting, the connection is rejected. Otherwise, the connection is accepted and normally processed.
filter_api(3), smtpd.conf(5), smtpd(8)
J. Klensin, Simple Mail Transfer Protocol, RFC 5321, October 2008.
The first version of filter-pause was written in 2015.
Joerg Jung <email@example.com>