HP-UX Mailing Services Administrator's Guide (B2355-91064)

Maximum message size (option MaxMessageSize)
This option restricts the maximum message (in bytes) that sendmail will accept from
a remote system. If a message larger that this limit is originated form the local system,
the message will be truncated to the limit.
To enable this feature uncomment the line:
O MaxMessageSize=100000
Forwarding Nondomain Mail to a Gateway
Mail that is being sent to a domain other than the sender’s domain can be forwarded
to a mail gateway. To have nondomain mail forwarded to a mail gateway, edit the DS
line in the /etc/mail/sendmail.cf file to specify the host name of the mail gateway:
DSmailgw.hp.com
Setting Mail Header Lengths
You can set a limit for the mail header. The maximum header length by default is 32768.
To change the mail header length:
1. Open the sendmail.cf file.
2. Set the value of the option MaxHeadersLength=n, where n is the maximum
number of lines allowed in the mail header.
If a mail header exceeds the maximum value, the following error message is displayed
to the sender:
552 Headers too larger #MaxHeadersLength
Limiting Message Recipients
By default, the maximum number of recipients is 100. You can limit the number of
users allowed to receive a single mail message. This helps to prevent the flow of spam
on the mail server.
• In the sendmail.cf file, set the value of MaxRecipientsPerMessage=n, where
n is the maximum number of recipients allowed for a single mail message.
After a message has been sent to the maximum number of recipients allowed, Sendmail
sends the error message 452 Too many recipients to the sender of the message.
This will work only when all the recipients of the mail message have their mailboxes
on the same machine.
Timeout.*
• You can set the total time spent in satisfying a socket control request using the
Timeout.control option. The default setting for this option is:
Modifying the Default Sendmail Configuration File 45