Google Message Security for Google Apps Administration Guide - Manual (Page 262)

262 Message Security for Google Apps Administration Guide
Click Update Blocked Domains.
Size Limits for Sender Lists
The maximum number of characters for each approved/blocked list in the
Administration Console is 4000. If each address or domain is 30 to 40 characters,
each sender list can include approximately 100 to 130 addresses and domains.
The maximum number of characters for all lists for each user in the Message
Center is 1000.
For each address, add an additional 2 characters to get an accurate count.
If you run out of space and attempt to add another address, you receive an error
similar to this:
List length limit (4000) exceeded
To free up more space, delete addresses that are no longer used.
You may consider adding an address from user’s list to the appropriate
organization-level list to improve filtering for all users, while freeing up space for
that particular user.
Using Batch Commands for Approved/Blocked Lists
Use the batch commands modifyorg and modifyuser to modify the approved/
blocked sender lists. For information on batch commands, see “ Batch
Processing” on page 381.
The batch-command syntax to add an address or domain to an approved/blocked
sender list is as follows:
modifyorg ORGNAME, approved_senders=ADDRESS_OR_DOMAIN
or
modifyuser USER_ADDRESS, blocked_senders=ADDRESS_OR_DOMAIN
or
modifyorg ORGNAME, approved_senders=+ADDRESS_OR_DOMAIN
or
modifyuser USER_ADDRESS, blocked_senders=+ADDRESS_OR_DOMAIN
ORGNAME The name or IID of the organization associated with the
approved/blocked sender list
USER_ADDRESS The address of the user associated with the approved/
blocked sender list
ADDRESS_OR_DOMAIN The domain or email address to add