Sending BT Yahoo after recent smtp verification changes

Question

BY Yahoo recently changed their smtp mail to require verification ( a process that requires registration of your password at the BT Yahoo website). In association with this the BT server has changed from 'smtp.btinternet .....' to 'mail.btinternet.com' for both incoming and outgoing mail.
However I, and others, have been unable to send mail from 'Mail in Mac OSX' since that time and the BT Helpline offers no solution ( I say that after more than 5 hours of talking to them, over 6 days including 'Rescue me' connection to my machine, confirming all my settings are correct.) .
Today I found a solution:
I deleted my mail accounts in 'Mail' and set up new accounts using the Leopard automatic feature.
This led me to discover that BT, in changing the outgoing server, failed to change the server name on the 'Equifax Secure Certificate Authority' - which still shows the previous server name.
The certficate can be 'over -ridden' although that leaves a security risk apparently as any server 'posing' as that name could be picking up my outgoing mail.
This lack of certification only shows up in Mac OSX when opening a new account.
I have found that over-riding the certification works (at least the server I'm connected to is passing on my mail!). ( choose 'connect' when the warning appears)
I have written to, and spoken to, BT broadband who seem totally uninterested - or perhaps they simply don't understand (it's hard to tell!).
There was a slight curiosity in setting up the new accounts - on my Mac Pro it all seems to work through port 110, while on my Powerbook it set up and worked through port 465. BT say that 110 is the correct port.

Answer 1

Gordon,
Port 110 is a proper port for an Incoming POP3 server, not using SSL. Port 465 is a port only used with an Outgoing Server/SMTP, and normally with SSL. You should not be finding these two very different port references in the same analogous position in Mail Preferences set up info?
Perhaps someone using btinternet will come along and be better informed, but I will try to help. Can you give me a link to a support site describing setting up email in any email program -- doesn't have to be Mail for me to interpret.
Ernie