debian exim4 smarthost and relay

[Harry Putnam <reader@newsguy.com>]

I hope this is the correct group for debian exim4 questions.  I'm sure
someone will point me elsewhere if not

 - Setup: New install of debian 10, in VBox vm attempting to get exim4
   working.
 - Internet host with no recognized or dns resolvable name, or domain
 - Receives dhcp address, but made mostly permanent by router
   capabilities

When editing a smarthost line in udpate-exim4.conf.conf
How does one enter a server that requires ssl 465.

Is adding 465 port all that is necessary? ..like

     dc_smarthost='smtp.server.com:465'

I've also seen two colons used while googling on this:

    dc_smarthost='smtp.server.com::465'

Which if any is correct?

-------       -------       ---=---       -------       -------

If one uses the port number in update-exim4.conf.conf is it also
required in passwd.client?

   smtp.server.com:465:user@some.domain:SECRETpw

And again .. one or two colons? Or is this not required?

-------       -------       ---=---       -------       -------
My googling has also caused some confusion to me about
editing something for smtp transport:

Will it also be necessary to edit something into smtp transport
regarding the use of ssl 465?  If so, can anyone show an example of
how that is done?