Guys, thank you very much for your replies!! I'm going to jump right into 'em if that's kosher:
You win a prize for detail, but what is it you want to do? Control playback from the desktop? If so, see Tremote on our wiki.
I suppose you've said, but I read half way through the message and didn't see it.
Again, apologies for the huge post-- I actually don't like not being able to figure things out, and since people around here tend to be very knowledgeable and helpful, I wanted to limit the amount of hand-holding you guys would have to do to help me get it properly set up. Not looking to win any prizes.
What I want to do is to use MC on my desktop to play the files physically located on my desktop to/via MC on my laptop.
The Tremote solution only works in reverse for me; I can see the desktop from the laptop, but not the laptop from the desktop. After reading your post, I again disconnected my laptop from the library on my desktop and quickly reconfigured the Tremote from the client/laptop, but it still came back up the same way: desktop can be seen under Playing Now on laptop, laptop cannot be seen on desktop.
One note: opening up the Media Server icon simply goes to MC itself, and as the Library Server and Media Server wiki pages both mention the feature is outdated, I've assumed that's normal. If not, let me know!
As a troubleshooting step, try turning authentication off; with authentication off can you see the laptop as a DLNA device on your desktop?
I originally assumed you were referring to the laptop, so I tried that again briefly (and went and did a couple of things around the house to give it time to recognize), and it was a no-go. I closed MC (and ended it in taskmgr) and relaunched, but the laptop is still not showing up as a "Playing Now" option on the desktop. I also tried unchecking Authenticate on the desktop (with it still checked on the laptop), and no dice. I tried unchecking both last night with the same result.
You don't mention wi-fi; what happens when your tablet is on the same Wi-Fi LAN (rather than using 4g)? Can you access both devices then? If so that might be a workaround.
Good call. It worked fine connecting to my desktop, but wouldn't connect to my laptop (and I tried it with and without Authentication selected). As far as it being a workaround, it is to a degree, but I have to reimport whenever I download new music this way, whereas I can just drop it directly into MC and have it play when I use the application directly from the desktop.
Based on the info you provided (changing the laptop to wi-fi broke the configuration, laptop only accessible from "outside the network," inability to use gizmo to control laptop from outside the network), it sounds as though there's a disconnect between the wired portion of your LAN and the wireless portion. The Gizmo test I suggested above will tell more about it, but it really sounds like you're having to go "outside the network" to reach your laptop.
I'm not an expert on these issues, but those troubleshooting steps should provide more info.
Based on the line of thought in your (very helpful!) post, that does seem more likely. As a quick attempt at a fix, I went back and power cycled my router, but it's still doing the same thing, so no luck there. I can reset my router if it's necessary, but it'll take me some time to save all my settings first. If it'll help, though, I'm all for it!
it seems to me you want to use Library Server and configure your file paths such that both server and client see the same paths. This can be done either using mapped drive letters or UNC-style paths. This allows you to have the client play back files "locally" - in other words, via Windows' file sharing instead of streamed via MC.
That may be the route I need to go; I'm not familiar with UNC file paths or what you're referring to with mapped drive letters in this instance, but I'll do some reading and try to figure it out. The odd thing is that my current setup has worked in the past, even (shortly) after I moved and re-set it up in my new apartment.
I didn't see any mention of setting the Client Option under Media Network. Be sure to check out the options there to allow the above, and to allow you to play music to remote MC zones via Library Server.
Totally reasonable point, but yes, I just went back and confirmed I haven't unchecked it or anything. I have all three checkboxes ('Auto sync with server,' 'Play local file if one that matches Library Server file is found,' and 'Show playback zones from the server on the client') selected on my laptop. In fact, those options are selected on my desktop as well, so I unchecked 'Show playback zones' on the desktop just to see if it would have any effect, and it actually neither caused the laptop to show up on the desktop Playing Now destinations, nor caused the desktop to stop showing up on the laptop (which is what I would have anticipated happening). Again, odd. Switched the desktop back to all three checkboxes though to minimize the number of variables we have at play.
You can probably ignore DLNA and WebGizmo options.
Those are my fallbacks in case I can't get MC working like I want it to, but that makes sense in regards to primary playback. Especially since we've already done so much to try to make those work here.
I'll start looking into UNC file paths, thanks for the tip MrC! If anyone has any other ideas, questions, or idle thoughts, please don't hesitate to share them. Again, guys, I REALLY appreciate the help you all are always so willing to give!!
I'll swing back by the thread in a while and see if there are any other moments of epiphany somebody wants to share