Does your ISP require the POP-before-SMTP authentication? It is whether you need to connect to the POP mail server within a certain time before sending mails. If so, there is a convenient way. To do that, put the following lines in your ~/.gnus.el file:
(setq message-send-mail-function 'message-smtpmail-send-it)
(add-hook 'message-send-mail-hook 'mail-source-touch-pop)
It means to let Gnus connect to the
POP mail server in advance whenever you send a
mail. The mail-source-touch-pop function does only a
POP authentication according to the value of
mail-sources without fetching mails, just before
sending a mail. Note that you have to use
message-smtpmail-send-it which runs
message-send-mail-hook rather than
smtpmail-send-it and set the value of
mail-sources for a POP connection
correctly. See Mail
Sources.
If you have two or more POP mail servers
set in mail-sources, you may want to specify one of
them to mail-source-primary-source as the
POP mail server to be used for the
POP-before-SMTP
authentication. If it is your primary POP mail
server (i.e., you are fetching mails mainly from that server),
you can set it permanently as follows:
(setq mail-source-primary-source
'(pop :server "pop3.mail.server"
:password "secret"))
Otherwise, bind it dynamically only when performing the POP-before-SMTP authentication as follows:
(add-hook 'message-send-mail-hook
(lambda ()
(let ((mail-source-primary-source
'(pop :server "pop3.mail.server"
:password "secret")))
(mail-source-touch-pop))))