Configure an alternate service account to represent the Exchange server. You can create a computer account or a user account for the Alternate Service Account (ASA).
Because a computer account does not allow interactive logon, it may have simpler security policies than a user account and therefore is the preferred solution for the ASA credential. If you create a computer account, the password doesn't actually expire, but we still recommend updating the password periodically. Local group policy can specify a maximum account age for computer accounts and there might be scripts scheduled to periodically delete computer accounts that do not meet current policies. Periodically updating the password for computer accounts ensures that your computer accounts are not deleted for not meeting local policy. Your local security policy determines when the password needs to be changed.
There are no particular requirements for the name of the ASA credential. You can use any name that conforms to your naming scheme.
Groups and Roles
The ASA credential does not need special security privileges. If you are deploying a computer account for the ASA credential, the account only needs to be a member of the Domain Computers security group. If you are deploying a user account for the ASA credential, the account only needs to be a member of the Domain Users security group.
The password you provide when you create the account is actually never used. Instead, the script resets the password. So when you create the account, you can use any password that conforms to your organization’s password requirements. All computers within the Exchange server must share the same Service Account . In addition, any CAS that are called on in a data center activation scenario must also share the same Service Account.