Mirrored local accounts to connect to database on different server and domain My database client and database server are on different machines and are not connected to the same domain (this is not supported with my web host). I'm not keen to send username/password details via a connection string and want to use windows authentication to connect to the database.

In this article's overview, it mentions this (emphasis mine):


  When you use Windows authentication to connect to SQL Server, you use
  either Kerberos or NTLM authentication depending on the configuration
  of your servers and domain. You might not be able to use Kerberos
  authentication if:
  
  
  Your database client and database server are separated by a firewall
  which prevents Kerberos authentication.
  Your application server and database server are in separate domains
  with no trust.
  
  
  In these situations, you can use either mirrored local accounts or SQL
  authentication. With mirrored local accounts, you configure two
  accounts on each server with identical user names and passwords. You
  must ensure that the passwords remain the same.


I'm assuming this just means creating a windows user with the same username and password on both machines, however I'm skeptical this would work. When I'm adding permissions for this user on the database client, it prefixes the username with the servername, and the same thing happens when creating a database login on the database server.

Is this what it means to create a mirrored local account? If so, how does this work considering the users are in different domains?
That is not a sql server question but a windows question.
If you have multiple computers, login on one with a local account and try to connect to another computer it will try to use the username and check it against its own local account database. If the passwords match the challenge/respone authentication will succeed.
As far as I remember the users have to be local accounts - on both sides.