Over the weekend my Technomancer hit a very basic point of disagreement with my GM: physical devices being hidden entirely inside hosts. My Crack Sprite failed to get onto the host when I sent it to set up Suppression before the rest of us tried to jump on, and thus alerted the host (and the spider). I decided to run the rest of the mission from outside the host, directly targeting the physical objects that were wireless-enabled rather than risking the IC and angry spider on his home turf (I was kind of hoping to draw him out here with me so I could fight him without the IC backing him up), but the GM ruled that none of the objects could be targeted – by Matrix or Resonance actions – until I hopped onto the host.
This completely doesn't match my expectations of how the Matrix works, but I couldn't find a reference that specifically said it works the way I think it does, either. The closest I could find was that you can get marks on a host in order to enter it through the direct-connection hack on an object slaved to the host, which seems impossible by his ruling, but that's kind of weak.
Please note this isn't a Rule Zero situation where the GM has looked at how the Matrix works and decided to change it for his game. This is his interpretation of RAW and RAI, not a house rule. We both admit we're rather new to this, and the Matrix chapter of the book is especially poorly written. Is there an expectation as to how this is supposed to work?
Clarification: I am logged onto the Matrix, but not into a specific host, just out on the grids. My GM's ruling is that physical devices can be not just slaved to (and thus benefit from the Firewall rating of), but also have their icons drawn into the host to make them completely immune to hacking unless the hacker has already hacked into that host.
Best Answer
(Please see my updated answer)
TL;DR: As a GM, I would call that the Technomancer is right, and the GM should rethink hacking devices slaved to hosts. If a device is wireless, you can hack it like normal, using the host's rating as a firewall (unless you have DNI, and then you just attack it directly). Just like a PAN, devices are still visible to the Matrix even when slaved. Icons in the host are assumed (by me) to be virtual. Look at the Dante's Inferno example if you want to know why I assume so.
I've been searching for prime book examples, but it's hard to find it spelled out. So, below is the research I did, followed by my conclusion.
First, on 216:
This sets what we already know: You can slave a device to a host. I wanna make sure we define what a host is, so on page 219 we find:
Simple enough, right? Hosts are servers on the cloud.
I found this bit at the top of 221 interesting:
Alright, so we've established that hosts can block people who are connecting from certain grids.
Page 224 has an example of attacking a host, but using a DNI and connecting directly to an offending unit. But they do say this:
This tells me he has the option of hacking the lock using the Matrix, but he'd have to go against the firewall. Instead, he's using a DNI, so no firewall. And he's not even on the host yet. Key piece of data there, but let's read on to see what else we can find.
I found a bunch more relating to the effects of attacking hosts, but that's not needed. Hmm, what else.
Ah, on page 233:
So, we've established that devices can be slaved to a host via a WAN. Alright. And it looks like you CAN attack a device without being on the WAN, as per the example, but you'd have to go through the host's firewall. Alright. And if you get a hit, you get a hit on the host, of course. Let's keep going just in case, but right now it's looking like the GM might need to rethink the rules. But, let's read on, I know there's more:
Page 236 gives us:
And later:
So accessing the host requires that you have a mark. But the previous example implies, to me, that you didn't have to have access to the host to hack the maglock. So far it all seems in line.
Page 239 has the Enter/Exit Host action, which requires a mark on the host. So, you'd have to be able to hack the host before you can get inside. And since slaved devices are hackable points, that tells me, still, you don't have to be on the host to hack the devices.
Page 246 says:
So, there's that. I guess hosts can ban people from a certain grid, but you can still hack into it from the public grid. You just won't be invited. But wait! I found a section about icons being drawn into the host!
Page 246 also said:
The thing I want to point out is that there's no mentioning of hosts being able to put their slaved device icons internal, because these are physical devices and they're just being slaved. So, if the device is wireless, then you can hack it. If it isn't, you need a DNI or access to the host.