Interesting.
If I use smtp.fasthosts.co.uk, I still get the phishing warning because of the email address listed as the sender, so it probably still wouldn't work (but we're not worse off than we were before). I'm still going to have someone test it, though.
If I use smtp.gmail.com with TLS/SSL and port 587 as per
here, I get Error 330 (net::ERR_CONTENT_DECODING_FAILED): Unknown error." which is obviously less than helpful.
If I try the same but going to AdminCP > Settings > Options > Cookies and HTTP Header Options and turning off gzip, I get
Code:
Warning: fsockopen() [function.fsockopen]: SSL operation failed with code 1. OpenSSL Error messages: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number in [path]/includes/class_mail.php on line 604
Warning: fsockopen() [function.fsockopen]: Failed to enable crypto in [path]/includes/class_mail.php on line 604
Warning: fsockopen() [function.fsockopen]: unable to connect to tls://smtp.gmail.com:587 (Unknown error) in [path]/includes/class_mail.php on line 604
If I use TLS/SSL with port 465, it acts like it's going to send the email but I get nothing (which is what Hotmail and Yahoo users see).