Google Message Security Batch Reference Guide - Manual (Page 202)

Batch Commands 205
If junk email messages are reaching your users because the sender is falsifying a
domain name in your Approved Senders list, and if this spoofed domain is vital to
your business and cannot be removed from the approved senders list, use this
batch command to set up an IP lock on this domain.
Note: To create these IP locks you can create a batch file which should be
maintained and kept up to date with all valid IP's for the allowed domain. All
messages sent to you from this domain with IP addresses not in the allowed IP
lock list will be bounced with a SMTP error:
550 IP Authorization check
failed - psmtp .
• -- The associated email config organization for this
IP lock. These configurations affect the email config organization and all sub-
organizations. The sub-org’s settings will be overwritten when parent org IP
settings change.
Enclose in double quotes or preceded with a ‘\’
symbol if it contains a quote (‘), double quote (“), backslash (\), apostrophe,
commas, #, = symbols.
• -- The name of the sender’s domain whose messages are
locked to this organization. This domain can be the message’s envelope
MAIL
FROM
address or the message’s header
From:
address.
• -- The Internet Protocol (IP) address used by the locked
domain.
• -- In addition to an IP address, a subnetwork can
be listed using Classless Internet Domain Routing (CIDR) notation. The major
CIDR blocks are:
/24 allows for a full class C
/16 allows for a full class B
/8 allows for a full class A