Found a nice article by Jason at http://blog.configmgrftw.com/?p=598
“Options” like /mp that are prefixed with a forward-slash are parameters for CCMSETUP itself. Thus, they control or affect the behavior of CCMSETUP and not the client agent. So, even though /mp contains the letters ‘m’ and ‘p’, this does not in any way mean that it sets the MP for the client agent. What /mp actually does is instruct CCMSETUP which MP to use to query for a DP (as mentioned above) thus bypassing the normal MP lookup.
Multiple MPs can be specified using /mp by separating them with a comma (this enables the lookup to try each MP in order if availability of the MPs is a concern):
Additionally, if an MP requires HTTPS communication, you should specify the prefix in URL format including the protocol:
It is always a good practice to use the full FQDN and ensure that name resolution is working for this name on the target clients. If name resolution is not working, you’ve got bigger problems that CCMSETUP cannot magically solve. Note also that CCMSETUP setup parameters require a colon between the option name and the value specified for that option.
“Options” like SMSMP that are in all capital letters are public properties that are not processed or used in any way by CCMSETUP but are instead passed directly to client.msi when CCMSETUP executes it. Thus, these properties do directly affect the client agent and its configuration. Note that you don’t actually have to specify the properties in all capital letters on the command-line, but it is best to do this so that they clearly stand-out.
SMSMP specifies the initial MP that the client agent uses (“initial” because with 2012, we can have multiple MPs within a single primary site and this will rotate periodically on clients). Without SMSMP, the client agent relies on normal MP location processes (AD, DNS, WINS) just like CCMSETUP does to initially set the MP that the client agent will use.
As with /mp, you should use the full FQDN of the MP and if an MP uses HTTPS, you should also specify the name of the MP in URL format including the prefixed protocol:
Unlike /mp, you can only specify a single MP with SMSMP. Also, public properties are not prefixed with a forward-slash and use an equals sign to set the value of the property.
One thing to make sure of is that you specify all CCMSETUP parameters on the command-line before you specify any public properties. This simply has to do with how CCMSETUP parses the command-line: it assumes that all parameters come first so as soon as it encounters a property, it stops looking for anymore parameters.
You can of course use both these options together which is common because the reason for using them is the same: you don’t want to (or can’t) rely on normal MP lookup. If MP lookup is working, then there’s no reason to use either. The only time to really expect any issues with MP lookup is when the target client is untrusted like when it’s in a workgroup. Remember that during a Build and Capture task sequence, the target/reference system should not be joined to a domain so specifying SMSMP in the Setup Windows and ConfigMgr task should be done – no need to specify /mp though because the source files needed by CCMSETUP are part of the client agent install package and thus already resident locally.
Although I haven’t tested explicitly and so I’m not sure of the exact ramifications, if a client is destined to be within a secondary site’s scope, you should still specify the MP for the primary site for both of these options instead of the MP at the secondary site. Remember, that clients always need to be able to communicate the MP in their primary site even if they are within the scope of a secondary.