Three different service account modes of SQL Server

1. SQL Server service account types include built-in system accounts and domain user accounts ", however, "built-in system accounts" are subdivided into three types: "local system accounts", "network service accounts", and "local service accounts ".
Different service account types in SQL Server online help are described as follows:
The local System option specifies a local administrator-level system account that does not require a password, similar to the local system account in SQL Server 2000.
The "Network Service Account" is a special built-in account, which is similar to the user account that passes authentication. The Network Service account and Users Group members have the same level of resource and object access permissions. Services running as network service accounts use the creden。 of computer accounts to access network resources.
The local service account is a special built-in account, which is similar to the user account that passes identity authentication. The local service account and Users Group members have the same level of resource and object access permissions. If the security of individual services or processes is threatened, the limited access permission helps to protect the security of the system. Services running as local service accounts will access network resources in the form of an empty session without creden.
"Domain user account" is a domain user account that uses Windows authentication to set and connect to SQL Server. Microsoft recommends that you use a domain user account with the minimum permissions for SQL Server, because SQL server does not require administrator account privileges.

We recommend that you use "domain user account" if multiple SQL Server servers communicate with each other in the actual environment ". In a personal testing environment, the Service Account type is based on your preferences.