## Connection Factory Object Properties >
Client Identification

Use this tab to re-specify default values of user name and password and to re-specify how a client will be identified (ClientID) to a broker. ClientId values are used mainly to keep track of durable subscribers.

Default Username Specifies the default user name that will be used to authenticate with the broker. The default value is `guest`.

Default Password Specifies the default password that will be used to authenticate with the broker. The default value is `guest`.

Disable setClientID() JMS API Specifies that client application is prevented from using API calls to change ClientID. It is generally better for you, the administrator, to control the assignment of ClientIDs.

If you check the box, you can use the Configure ClientID as field to specify a ClientID for the client. If you don't specify such a value, a default value consisting of the client' host's IP address is assigned by the system. While this is done as a convenience for developers, it prohibits a client application from creating more than one connection: the system does not allow two connections with the same ClientID.

Configure ClientID as Specifies an identifier for the client. If you don't specify this value and you have disabled the api call that sets the ClientID, a default value consisting of the client host's IP address is assigned by the system. While this is done as a convenience for developers, it prohibits a client application from creating more than one connection: the system does not allow two connections with the same ClientID.