SMTP
This means the server you use to send mail out through

The SMTP server name is mail.yourdomain.co.nz or yourdomain.co.nz

Note:

Outlook Express
If you use the NZservers mail server you will need to set Outlook Express authentication settings to validate the password.

Choose Tools, Accounts and select the mail tab
Select Properties and then Servers and choose 'Outgoing Mail Server Option'
Tick the box that says 'My server requires authentication' Click the settings tab and make sure the use same settings as the incoming mail server

Pegasus Mail 4.x

Open Pegasus Mail and go to the drop down menu called Tools, then select Internet Options.

Complete the SMTP Host with yourdomain.co.nz.