[Galaxy Tab 2 Q&A, Help & Troubleshooting] onenonlycasper:
Barnacle tethering not usually supported with Galaxy Tab 2 7.0

As far as I can tell and in my experience with Barnacle and my Galaxy Tab 2 7.0, the issue often is that the Galaxy Tab doesn't support viewing or connecting to ad-hoc networks. And most, if not all, of the apps available on the play store that say they can tether your wifi are set up by using an AD-HOC network to share their internet. So if you are trying to do what many people are then I assume you are using a android mobile phone to share the internet connection to your tablet, am I correct??

I have been asked by a couple of people about the possibilities of using their phone to tether their wifi connection to their android tablet, and it typically does not work. But I have found after hours of searching in these forums and on other sites that there are some scenarios in which you might be able to configure the two devices (with root of course, possibly with a patch and some file adjustments, or even maybe through a mod on both the phone and the tablet) so that they can share your mobile internet connection wirelessly. If you look in the forums for either your phone model and/or your tablet model you will find that some people have fixed the issue with wifi tethering from phone to tablet with the tools I mentioned. It seems like a common method that works for some people involves first having root access on both the tablet and the phone, then with the correct "wpa_supplicant" patch or mod, it is possible to fix the problem but I have tried it several times on different devices and with different methods to the process and only 1 time did I successfully get a decent internet connection from a mobile phone to an android tablet (it was on a galaxy tab2) while using a third party app from the google play store.

So it's not entirely impossible to tether your phone internet to tablet using an app like Barnacle or the other dozens of wifi tethers in the play store and even on other sites, but it just doesn't seem to be consistent on all devices and there isn't one exact or simple way to actually fix the issue. The alternative way to share your phones internet through wifi to a tablet that has always worked for me is if your phone actually has its own wireless tether or mobile hotspot app or function already built-in to the system. This type of wifi tethering does not use AD-HOC networking so there is no issue when it puts out a wifi signal for your tablet to pick up. I would definitely say keep searching in the forums here and even on the web in general for new apps for tethering or possible mods that fix the issue because there are a lot of people having this issue so chances are there are people working on a solution to the problems. Another way I've seen a friend get around the problem is by of course rooting his phone flashing recovery then installing a custom rom that had a mobile hotspot feature built-in to the system (because at that point his phone did not have the same feature in stock rom or system, and the many different wifi tethers we tried to use didn't seem to work on his tablet either). It took a lot of trial and error, meaning we had to just keep trying different apps, roms, set ups, mods, basically anything we could adjust or add to the phone and sometimes even the tablet, we tried over and over using different phones and a few tablets all different models and manufacturers just to see what might work. In the end he was using his HTC phone (i think it was an Incredible) with root and a custom rom that had mobile hotspot feature already in system as an optional tether, and we got a few different tablets to connect without any real issues, but each tablet is different so every now and then one of us had to play with settings or at the most root the tablet and tweak things to get a good stable and consistent internet connection from his phone that ultimately was coming from his wireless cellular service which was 3G on VZW back then.

With all of that stated, goodluck with your tethering, and I hope something I said might have helped you in any way or at least explained what the issue could be......I guess what I'm trying to say in general is that the stock galaxy tablet system doesn't pick up the AD-HOC type of network that most of those wifi tethering apps usually use to share the internet connection. So if there is any chance of getting it to work, it all depends on different tablet models or phone models or again the simple fix is not to use a tethering app and to use the built-in function or mobile hotspot feature that some phones have already. Or just do what I do, and keep searching forums and websites for different methods that other people have found that work and try them out for yourself to see if it applies to your set up as well.

Gdluck,

OneNonlyCasper