Administration Guide : Security settings : Editing an existing ACL

Editing an existing ACL
Clicking either the Edit subtab or the Edit icon from the Summary page.
Note: Access Control List name (ACLs): Due to a limitation of the use of ACL's with Portal, in addition to designating specific server access, the address of the Portal server must be included for Change Password and Collection downloads to function properly for Portal users.
If the User can change password option to true in the Volumes/Users > Users > Edit User tab, then set the Access Control List Name and IP Host (name or N.N.N.N) in the AFP/Access > Access Restriction (ACLs) > Edit ACL tab. Each IP Host added will display in the Access Granted List.
To editing an existing ACL
Select the ACL in the Select ACL to edit pop-up list.
If you’re creating a new ACL based on an existing one, change the name in the Access Control List Name type-in box. If you truly want to edit an existing ACL, leave the name alone.
AppleTalk Network Range [Will not appear on Windows and OS X servers] Click Add after entering the range.
IP Network
Enter the IP address and use the Add with ... pop-up list to select the number of significant bits. Setting the significant bits allows you to decide how much of any incoming IP address should be tested against the acceptable entries.
An IPv4 address is a 32-bit number, some part of that signifying the “network” part, and the rest being the “host” part (in an address like #.#.#.#, each # represents 8 bits). The bits are consecutive, starting with the left (Most Significant). How many bits are the network part, however, depends completely on your local configuration.
IP Host (Click Add after typing in a host address or name)
Login Account (The Account is added automatically upon selection. You can always delete an Account if you make a mistake.)
Group (The Group is added automatically upon selection. You can always delete a Group if you make a mistake.)
Existing ACL (The ACL is added automatically upon selection. You can always delete an ACL if you make a mistake.)
Each item you add will appear in the Access Granted To list. You can delete any item from that list using the shaded Delete icon next to it.
When you have finished editing, click the Submit button to register your changes.