You can determine the connector ID by using the central logs or by using the idsync printstat command.
You can find the connector ID of the directory sources being synchronized by looking in the central audit log. At start up, the central logger logs the ID of each connector and the directory source that it manages. Look for the last instance of the startup banner for the most recent information.
For example, the following log entry contains two connector IDs:
CNN101 is a Directory Server connector that manages dc=example,dc=com
CNN100 is an Active Directory connector that manages the example.com domain
[2006/03/19 00:00:00.722 -0600] INFO 16 "System Component Information: SysMgr_100 is the system manager (CORE); console is the Product Console User Interface; CNN101 is the connector that manages [dc=example,dc=com (ldap://host1.example.com:389)]; CNN100 is the connector that manages [example.com (ldaps://host2.example.com:636)];"
For information about using the idsync printstat command to determine the connector ID, see Using the idsync printstat Command