Hi I have two requirements , need to restrict opening site from both SharePoint designer and Infopath form.  I could do restrict SharePoint designer access either Webapplication level or site collection level but I am not finding any options to restrict infopath form access. How to do it? please let me know if you know it. thanks in advance.

To restrict access to the site, remove their permissions from that site so that they will not be able to open it or any list from Infopath