When a user with a valid credential from LAN Manager logs in to Adaptive Server, the server checks whether the name is listed as a user in master..syslogins. If it is, Adaptive Server accepts that user name.
For example, a user logs in to LAN Manager as “ralph”, and “ralph” is listed in master..syslogins. Adaptive Server uses all roles and authorizations as defined for “ralph” on that server.
As an alternative example, a user with a valid credential logs in to Adaptive Server, but is unknown to the server. Adaptive Server accepts the login only when a secure default login has been defined with sp_configure. Adaptive Server uses the default login for any user who is not defined in master.syslogins, but who is validated by LAN Manager.