Sendmail 8.9.3 Release Notes

12 Chapter1
New and Changed Features
New Features
sendmail.cf with loose_relay_check
sendmail.cf with promiscuous_relay
The sendmail.cf file generated using this script will differ from the
default sendmail.cf file provided in the /usr/newconfig/etc/mail
directory with respect to the check_* rulesets(check_mail, check_relay,
check_rcpt) only. All the other options are identical.
New Configuration File Options
Described below are the new configuration file (sendmail.cf) options
added in sendmail-8.9.3.
• MaxHeadersLength
This option will limit the maximum length of a mail header. If the
maximum length exceeds the limit, it will send an error message "552
Headers too large #MaxHeadersLength" to the sender of the mail.
The default maximum length is 32768.
This option is set using,
O MaxHeadersLength=32768
This option is commented out in the default sendmail.cf file.
• MaxRecipientsPerMessage
This option will limit the number of recipients for a single mail
message (a common feature of spam messages) if the recipients of the
mail message are having their mailboxes on the same mail server. For
example, if users Tom, Dick and Harry have their mailboxes on
machine test and if the MaxRecipientsPerMessage is set to 2 on
machine test then, if a message is sent to Tom, Dick and Harry then
the message will be delivered only to Tom and Dick while it will be
discarded for Harry.
The maximum value for this option is 100. It can be changed
depending on your network. After the maximum number is reached,
sendmail returns error message "452 Too many recipients" to all
RCPT commands. This feature can be used to discourage the use of
the mail server for spamming.
This option is set using,
O MaxRecipientsPerMessage=100
This option is commented in the default sendmail.cf file.