DKIMProxy and port 587

[kaosmonk]

Hi guys,

I'm setting up Zimbra OSE 7 and have a question in regards to some of the DKIMProxy concepts. For the record, I've followed this howto on setting it up. In that manual, submission port is 'used' for signing, so I wonder if I need to tell my Zimbra Desktop client users to configure their clients for sending out emails through port 587? If yes, how to do that, as I do not seem to see that option there?
On the other hand, what's happening with the emails sent through webmail Zimbra interface? Do they get signed too and do I have to change anything in order to send all outbound emails through port 587?

I do admit that my thoughts are misleading and that I do not get the concept right, but I'd appreciate any help on this one.

Thanks in advance!

[kaosmonk]

If judging by this post, it seems that by checking these two options on the MTA tab in Global Settings, I'll force port 587 usage, right? Would that affect only web client users or even those using Zimbra Desktop?