Recently a customer wanted a new external Url for SharePoint (intranet.domain.com). I implemented it via Zones and alternate access mapping and so far it works fine. They also stopped using their internal url and use the intranet now everywhere.
Now it occured that users got emails whos links point to the internal SharePoint url instead of the external intranet url. It probably wouldn't be as much of a problem if there would not be a authentication problem with SharePoint and access via its internal (servername) url since some changes to the iis authentication methods.
I found a technet article which proposes a Cmdlet to update the urls of old Alerts and this is fine. But now I ask myself if new alerts might again use the internal url, or, if the site is only used via intranet, email links from new alerts will also use the intranet url.
Then I would also like to now what happens if I change the Default Zone to intranet[...]. Would this break SharePoint or is it a good idea (if the internal url isn't needed any more) to fix more of these "old urls used" problem?
Note: SharePoint 2010 is used