Networking: screen sharing problems

Discussion in 'Mac OS X Server, Xserve, and Networking' started by jmfm, Nov 23, 2010.

  1. jmfm macrumors newbie

    Joined:
    Apr 17, 2010
    #1
    Hi,

    I have a strange problem when I try to connect to another Mac in my home network via screen sharing. Here's what happens in case somebody can help me.

    I'm trying to do this via Finder. I go to 'Shared' on the left column of finder and place my cursor on the name of the other computer in the network and I click on the 'Share Screen' button. When I do that, a little screen pops up saying "contacting 'other computer'"

    And after a while, the following error message appears:

    "Connection failed to 'other computer'"
    Please make sure that Screen Sharing (in the Sharing section of System Preferences) is enabled on the computer to which you are attempting to connect. Also make sure your network connection is working properly."

    However, Screen Sharing IS enabled in System Preferences (on both computers). I disabled the firewalls on both computers as well in case that was the cause of the problem.

    I have been wracking my brain trying to troubleshoot this and I've found some strange things that might be connected to the problem.

    I think I must have messed up something changing the name of the other computer. This is a computer that I have in another room of the house (from now on 'Computer 2', 'Computer 1' being my computer, the one I'm trying to connect from). In this computer I have various accounts for my children, for myself and for guests. The thing is that before the computer used to have another name (I don't remember the exact name) and then I changed it to Marta. (Note: the time also coincided with the upgrade of OS X to 10.6.5)

    Since I did that, when I look at the public folders in Computer 2, things are a bit amiss.

    The first thing I notice is that now the public folder looks different from the other folders:

    http://img146.imageshack.us/i/computer1mountfinder.png/

    View of the folder on the desktop:

    http://img717.imageshack.us/i/computer1mountdesktop.png/

    i.e it doesn't have the three little guys that mounted folders usually have.

    The second thing I notice is that now I can drag files to that public folder but I can only see the files that I have put in there at the moment. If I turn off the computer and turn it on again, I cannot see those files any more. Nevertheless, the files are there. I can see them when I go physically to computer 2 and I look at the contents of the public folder.

    Furthermore, I noticed that if I click on 'connect as' and I introduce the login name and password for my daughter's account, then I get to see another folder called 'mfm' (her user's name) which I don't see before doing 'connect as':
    http://img163.imageshack.us/i/mfm.png/

    Now, what you have to understand is that 'mfm' and 'Marta' are the same. That is, 'Marta' is my daughter and the name that I gave the computer. 'Marta's public folder' and 'mfm' are in fact also the SAME folder. If I do 'connect as' and enter mfm plus password, I can see all the files that I dragged to 'Marta's public' folder.

    So my hypothesis (for lack of a more reasonable one) is that I must have done something (probably when I changed the name of the computer to Marta) that has screwed up the network settings and now the computer is not recognized when I try to do 'Screen sharing'.

    If I try to do screen sharing from Computer 2 to Computer 1, things work smoothly. I get a pop up window with two options:

    . Enter your name and password to share the screen of Josep M. Fontana's iMac (my computer)

    - by asking for permission
    - as a registered user

    Then I give my user name and password and I can do screen sharing with no problems.

    As I said, when I try to do this from computer 1 to computer 2, I am not offered any options: a little screen pops up saying 'contacting "Marta"' and it stays there until I get the error message.

    I've wasted a lot of time trying to figure out what the problem is. I would REALLY appreciate any help anyone can give me to solve this problem.

    Thanks in advance.

    Josep M.
     
  2. milbournosphere macrumors 6502a

    milbournosphere

    Joined:
    Mar 3, 2009
    Location:
    San Diego, CA
    #2
    Josep, have you verified that Screen Sharing is set up to have access via the sharing panel in the System Preferences on computer 1? That's only thing I can think of considering that things work perfectly fine going the other way. Also, are you looking at computer 1 when you're trying to connect? It could be that permission is required to share computer 1's screen, and you're missing the pop-up on computer 1's screen. Hope this helps!

    From Apple: http://docs.info.apple.com/article.html?path=Mac/10.6/en/11848.html
     
  3. svenwillmann macrumors member

    Joined:
    May 6, 2008
    #3
    I am not quite sure if I understand your problem correctly, but I had screen sharing issues before and solved it the following way:
    - start the screen sharing app in /System/Library/CoreServices/Screen Sharing.app
    - go to Connection -> new
    - type the name of the computer to connect to eg. nameofcomputer.local
    - enter the name of the user as "Mark Smith" (instead of marksmith as the name one usually would enter)

    It solved my screen sharing problem using the name displayed not the actual user name (as stated above "Mark Smith" not "marksmith")
    In your case it will probably be 'Marta' instead of 'mfm'.
    Not sure if this helps.
     
  4. FourCandles, Nov 23, 2010
    Last edited: Nov 23, 2010

    FourCandles macrumors 6502a

    Joined:
    Feb 10, 2009
    Location:
    England
    #4
    Just one more idea:

    Following exactly what you've said above, I think you must have a username and password for Computer 2 saved in your Keychain on Computer 1, otherwise it would be asking you for a user/password as it does when connecting the other way. Maybe with the various changes you've said you've made, this user/password is no longer valid. Try going into your keychain on Computer 1 and seeing if there's something stored for Computer 2. And/or, log in as a different user on Computer 1 and then try to Screen Share Computer 2.
     
  5. jmfm, Nov 24, 2010
    Last edited: Nov 24, 2010

    jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #5
    Thanks milbournosphere,

    Screen Sharing is set up on the two computers.

    I'm sure it is not a matter of confirming permission. I don't even get the chance to request permission. No pop-up appears on the screen. I just got a MacBook air and tried to do Screen Share right next to Computer 2 (Computer 2 is actually the one I'm trying to connect, using the terminology I established in my first message). I don't see any pop-up appearing when I click on the "Share Screen" button.

    Again, when I try to do the same from Computer 2 to the MacBook Air, screen sharing works fine.


    JM
     
  6. jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #6
    Re: Networking: screen sharing problems

    Thanks svenwillmann,

    That didn't work either. I have the same problem as when I tried to do that from Finder. When I introduce Marta.local after Host:, I get the same pop-up saying "Contacting Marta.local" and it stays there until I get the error message that says that I should make sure that Screen Sharing is enabled.

    Actually, I am pretty confused with all the naming scheme. 'mfm' is the short user name for one of the accounts in that computer but actually the name of that particular account (as set up in System Preferences > Accounts) is also 'Marta'. When I access the terminal inside this account called 'Marta', I get 'mfm' at the prompt. Furthermore, even though, the account's name is 'Marta', the home username that appears in Finder is 'mfm', not 'Marta'. What is the difference between the account name and the home username? Shouldn't they be the same? How/where does one modify the home username?

    But wait, it gets more confusing (for me at least, coming from the Dark Side of Windows PCs).

    The name of the computer is also 'Marta', as set up in System Preferences > Sharing > Computer Name:. OK, so when I am on Computer 1 (or on the MacBook Air), I see 'Marta' under shared. That's OK. This is the way it is supposed to be because I'm seeing the computer name. But sometimes I also see another icon that says 'mfm' (it is also a computer screen but it has a different color: darker blue). While I can see all the public folders for the accounts on Computer 2 when I click on Marta, I see nothing when I click on 'mfm'.

    One more thing :) (I have to pay homage to Steve in spite the problems I'm having) I forgot to say this in my first message but I'm able to connect to Computer 2 from Computer 1 or from the MacBook Air from Finder by clicking the button 'Connect As...' and introducing the username and password of any of the accounts in Computer 1 (including Marta/mfm). This makes it more difficult to troubleshoot because it seems clear that it is not a problem with the network connection. I can see the contents of all the folders without any restrictions once I access this way. I just can't do Screen Sharing.

    JM
     
  7. jmfm, Nov 24, 2010
    Last edited: Nov 24, 2010

    jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #7
    Re: Networking: screen sharing problems

    Thanks FourCandles,

    I think I might have confused you guys with the naming of the computers. I think you mean to say Computer 2 when you say Computer 1 and viceversa. Computer 2 is the one I'm trying to connect to via screen sharing (say "the server") and Computer 1 is the one I'm trying to connect from ("the client").

    OK, I went to Utilities > Keychain Access in Computer 1 and I didn't see anything stored which might be related to Computer 2 (under Category All Items). I cannot see anything related to Computer 1 in Keychain Access on Computer 2.

    I think that this is not the problem since I've tried to access Computer 2 from a new MacBook Air (which I had never used to try to access Computer 2) and I encounter exactly the same problem.

    The problem is not only with one of the accounts in Computer 2. At the beginning I was trying to do screen sharing when I was logged in as 'Marta' (or 'mfm', see the other message). After that I logged into the Admin account and into another account I have in that computer: same problem.

    It's so frustrating. Here in the MacRumors forums at least I have gotten 3 responses (you guys rock) but in the official Apple forums I still have not gotten any response. Bearing in mind that some "official" Apple people might hang out in those forums, I take it that my problem is a hairy one.

    By the way, do you guys know whether there is somewhere where I can post this as a bug or as a request for help directly to Apple?


    JM
     
  8. milbournosphere macrumors 6502a

    milbournosphere

    Joined:
    Mar 3, 2009
    Location:
    San Diego, CA
    #8
    Okay, let's see if we can get more specific info on the error that occurs. Why don't you open the console and see what the output is when you request the connection? Perhaps posting that info here would give us a better idea of what's going on.

    http://en.wikipedia.org/wiki/Console_(Mac_OS_X)
     
  9. jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #9
    Thanks milbournosphere!! With your help I'm much closer to solving the problem.

    This is one of those "Duh!" moments.

    OK, so I haven't solved my problem but your suggestion to check the console log (I should have thought of this, hence the "Duh!") shed the light I needed to start solving this mystery.

    I'm attaching the console log (Marta_All Messages_26_11.txt) with the relevant lines so that people who have more expertise than I do on these issues can help me find a solution. It looks like I have a hidden firewall that is not allowing connections through certain ports.

    Let me explain this a little better. A while ago (when the computer named 'Marta' was my main computer) I installed an additional firewall called WaterRoof (http://www.hanynet.com/waterroof/). You see, I come from the PC world and that had made me very sensitive about security issues. Anyway, the thing is that I UNINSTALLED the damn thing quite a long time ago. I had even used an app called AppZapper (http://www.appzapper.com/) which is supposed to do a very thorough uninstallation job.

    As you can see in the log, though, WaterRoof seems to be still alive and kicking on that computer and it seems certain that this is what is responsible for my inability to connect to that computer via screen sharing. The computer was turned on at 8:53. At around 9:00 I made the first attempt to do screen sharing from the other computer. You can see that around that time some TCP connections are denied.

    I'm trying to figure out how to get rid of WaterRoof. I've done some searches via spotlight but I cannot find any related file. Google searches with 'WaterRoof' and 'uninstall' do not yield any useful results, either. What I fail to understand is why is WaterRoof still active (or any firewall for that matter) if I have the OS X firewall deactivated in my System Preferences. From what I understood, WaterRoof is only a frontend that allows you to tinker with the default Mac firewall in a more sophisticated way than the default GUI allows.

    I would appreciate any help you guys can offer to take the final step to solve this problem.

    Josep M.
     

    Attached Files:

  10. svenwillmann macrumors member

    Joined:
    May 6, 2008
    #10
    I have a feeling that waterproof tempered with your ipfw

    what does the following command tell you in terminal

    $ sudo /sbin/ipfw list
     
  11. milbournosphere, Nov 27, 2010
    Last edited: Nov 27, 2010

    milbournosphere macrumors 6502a

    milbournosphere

    Joined:
    Mar 3, 2009
    Location:
    San Diego, CA
    #11
    When in doubt, format. :) No, I agree with the previous poster. Looks like WaterRoof managed to mess things up for you. Let's see what it did to your ipfw. It looks like WaterRoof is simply a frontend GUI for ipfw, so even though you uninstalled it, the rules it created are probably still in use by the mac. My guess is that some additional cleanup will be required. Glad I could help!
     
  12. jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #12
    Re: Networking: screen sharing problems

    Thanks svenwillmann and milbournosphere.

    That is indeed what was happening. I was a little confused about IPFW. I wasn't aware of the fact that OS X has two different firewalls. Since I had the default firewall (the one that is managed via System Preferences) deactivated, I could not understand how certain rules could still be active.

    I did some googling and learned about IPFW. What I did then was simply reinstall WaterRoof (nice little free app) and flush all the active IPFW rules. Now everything is working as it should.

    Thanks a lot for your help. This forum seems to better than the official Apple forums to obtain help :)

    Josep M.
     
  13. svenwillmann macrumors member

    Joined:
    May 6, 2008
    #13
    haha...
    ... thats what we want to prevent here ;-)

    glad it is working now

    just on the side
    I believe you could have achieved this by using following in terminal (without installing waterproof again)

    $ sudo /sbin/ipfw -f flush
     
  14. milbournosphere macrumors 6502a

    milbournosphere

    Joined:
    Mar 3, 2009
    Location:
    San Diego, CA
  15. jmfm thread starter macrumors newbie

    Joined:
    Apr 17, 2010
    #15
    Thanks guys,

    Yes, you are right. Once I understood what the difference between the default firewall and ipfw was and WaterRoof did, I didn't mind reinstalling WaterRoof, though. It is really a nice front end.

    Josep M.
     

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