Hi Drojas,
Some information regarding the different security settings are given below
•Restricted- Corresponds to Internet Explorer#%92s Restricted sites zone (high security).The form cannot access resources that are external to the form, such as Active X controls. Users can open and save forms but the script code cannot access the file system or other computer resources. The restricted model prevents use of custom task panes, data connections (except submission by email), managed code (VB.NET or C#) and roles.
•Domain- Corresponds to Internet Explorer#%92s Local Intranet Zone (medium low security) or forms running on the local computer during development. Forms can access databases and web services within a single domain. For example –forms running in the local oakleaf.org domain cannot access web services provided by a server in the public oakleaf.ws domain. Templates deployed to server shares on a local area network are considered to be in the same domain. ActiveX Controls, custom task panes, roles, managed code are enabled. This model is the most common security scenario for Published InfoPath forms.
• Full Trust- Corresponds to Internet Explorer's Trusted sites zones.(low security).These forms permit cross domain data access, permit running ActiveX controls that aren't marked safe for scripting, provide added managed code flexibility, and eliminate some security level prompts we receive at the domain security level. But we must sign the form with a code signing certificate or deploy the fully trusted forms to user's computers.By default InfoPath analyses our form and its programming code to automatically assign the most restrictive security model. However we can over ride this automatic security model assignment.
Regards,
Abhishek