I just want to be clear that Telstra Mail is not a mail client software and it refers to the mail platform that your emails are hosted on.
Customers will have the option to configure their email program with POP or IMAP configurations. This link provides information about the differences between the two protocols.
You can find the email configurations for all three mail platforms currently used by BigPond mailboxes here. If your mailbox is not currently on Telstra Mail, then you will need to manually configuring the settings to match the POP servers under BigPond email settings.
I hope this helps.
- Shelly