You can use DSCC to perform this task. For information, see Directory Service Control Center Interface and the DSCC online help.
Configure the mapping for unauthenticated clients.
$ dpconf set-server-prop -h host -p port \ user-mapping-anonymous-bind-dn:anonymous-mapping-bind-dn \ user-mapping-anonymous-bind-pwd-file:filename
The mapping for anonymous clients is configured in Directory Proxy Server because the remote LDAP server does not contain an entry for an anonymous client.
For information about permitting unauthenticated users to perform operations, see To Configure Anonymous Access.