Tim you are my hero.
Just so you know my name is Sandy....Gary's other half. So he is not gay, not that there is anything wrong with that
So we truly thank you as all is working now. Just need to be careful re Spamming, Viruses and so on now that I have disabled SSL.
Cheers,
Sandy & Gary.
The only issue with Port 25 relay is that, in 'ye olden days' when the Internet was just getting going, the 'grandfathers and grandmothers' of the Internet who put together all the standards thought that it would, of course, be necessary to use a password to receive email but they never thought it would be necessary to have a password to send email. After all, you pick up your regular (paper) mail from a secure mailbox, but you can pop your new mail into any letterbox.
But the problem is simply that, if you don't have security on sending mail, anyone can send mail pretending to be you. After all, all they need to know is your email address - there's nothing else needed to set up a Port 25 SMTP account. So someone could start sending malicious emails purporting to have come from you. This happened at my University a few years ago when some students thought it would be funny to circulate emails, supposedly from the Head of Department, saying he was resigning!!!! After that, we banned Port 25 relay too!!
When you're sending from home, there's not a problem because your DSL line has to have an account and password to log on so Optus know it's you - or someone authorised by you - using that DSL line, so there's not a problem with Port 25. So that's why your PC worked OK. But on the 3G card Optus receive the Port 25 request over the general Internet and they have no way of confirming the identity of the originator.
Have a great weekend...
Tim