Apparently, no one uses SMTPClient because there is a bug that has lingered for ages. Using it raises the following Squeak error message:
TelnetProtocolError: 501 malformed auth input (#5.5.4)
Here's my test Squeak method:
mailTo: userAddress subject: subject text: text
....| client |
....client := SMTPClient openOnHostNamed: 'host_mail_server' port: 25.
....client user: 'my_user_id'; password: 'my_password'; login; initiateSession.
....client mailFrom: 'my_email_address';
I managed to find a fix. In the #encodeString: method of the #SMTPClient in the Network-Protocols package, amend the last statement to read:
....^ str truncateTo: (str size - 2)
Perhaps it will be fixed in the next Squeak release. It's probably very low priority as I seem to be the only person who cares about it.