Here is info I researched -> Medium level, but with additional restrictions
And as you see :) them a leading host in hole world O.o

As a leading web host, we need to make sure that the resources on our systems are distributed fairly and that no single application has a negative effect on the other applications or on the whole system. It is therefore essential that we define a so-called trust level for the use of ASP.NET applications that restricts certain features of the .NET framework.

For instance, no ASP.NET application may access the registry or carry out file accesses outside a particular user directory. Nor may the execution of so-called “unmanaged code” (i.e. code that is not administrated by the .NET framework and which, for instance, carries out its own storage administration) be permitted.

You will not be able to access an Microsoft Access database via ODBC or OLEDB because these procedures still contain the "unmanaged code" as mentioned before. You will therefore have to use Microsoft’s SQL server and the corresponding classifications in the .NET framework (System.Data.SqlClient) if you want to run ASP.NET applications with a database.

The other restrictions set by the trust level are of little relevance to the majority of ASP.NET applications. They include the non-availability of so-called IsolatedStorage and the barring of the system’s environment variables. For safety and performance reasons, ASP.NET applications cannot be traced or debugged by the server. Any non-present or non-accessible backend services such as MessageQueues, DirectoryServices, Printing or PerformanceCounter cannot be addressed via an ASP.NET application.

Some other restrictions are:
Access to the .NET Framework isolated storage
Use of system printers
Control of security relavant infrastructure like ControlAppDomain, ControlEvidence, RemotingConfiguration, UnmanagedCode and others
Access to the registry
Access to confidential environment variables
Create or open network sockets
Access to the system event log
Access to system performance counters
Use of the .NET Framework Data Provider for OleDb and ODBC

just received answer from help center

Dear client,
Thank you for contacting us.

Shared Hosting packages runs on a Medium Trust Level.
While on Server packages, runs on a Full Trust Level.
Your package is a shared hosting package, so it already runs on a Medium Trust Level.

Do I really need Full Trust Level?

FYI I checked and EnvironmentPermissions has the following definitions in the web_mediumtrust.config :

.net 2.0 version:

<IPermission class="EnvironmentPermission" version="1" Read="TEMP;TMP;USERNAME;OS;COMPUTERNAME"/>

.net 4.0 version:

<IPermission

                                    class="EnvironmentPermission"

                                    version="1"

                                    Read="TEMP;TMP;USERNAME;OS;COMPUTERNAME"

                            />

As you can see the ability to read the computername (which I would assume is the link demand that getMachineName() requires) is a default permission –so it surprises me that people are seeing this issue -please note dotnetnuke.com runs under medium trust and is using the client dependency framework without seeing this issue. I suspect there may be something else at play here but i'm not sure what it is.

 

---

Buy the new Professional DNN7: Open Source .NET CMS Platform book Amazon US