Fixed server roles can be mapped to the more specific permissions that are included in SQL Server 2005. The following table describes the mapping of the fixed server roles to permissions.
bulkadmin
Granted: ADMINISTER BULK OPERATIONS
dbcreator
Granted: CREATE DATABASE
diskadmin
Granted: ALTER RESOURCES
processadmin
Granted: ALTER ANY CONNECTION, ALTER SERVER STATE
securityadmin
Granted: ALTER ANY LOGIN
serveradmin
Granted: ALTER ANY ENDPOINT, ALTER RESOURCES, ALTER SERVER STATE, ALTER SETTINGS, SHUTDOWN, VIEW SERVER STATE
setupadmin
Granted: ALTER ANY LINKED SERVER
sysadmin
Granted with GRANT option: CONTROL SERVER
The public role is granted VIEW ANY DATABASE permission.
Members of the securityadmin fixed server role can grant both server-level and database-level permissions.