Unknown PC sometimes showing up on sidebar

Question

Level 1

14 points

Unknown PC sometimes showing up on sidebar

Hi,

I have noticed an unknown pc showing up on sidebar, which means they are in my network. A month ago, the pc name is hpc, and now the name is home-jh. It is pretty annoying they exist there.

I have AirPort Express but I unplugged it for a day and the pc still shows up on the sidebar. I have 4 printers but the printer names do not match hpc and home-jh. I have iPad and iPhone, but I don't think they will show up on the sidebar.

I have run netstat commands on both PC and Mac. Is there any way I can track their public IP or IP since I just know the host name.

I am suspecting a hacker is DNS cache poisoning my router DNS cache because I freqnetly find my Chrome/Firefox/Safari browser usually say it cannot find the website, say, Google, or many big-named sites despite my internet connection is normal. When I wait few seconds or restart my computer, browsers is functioning normal again.

I have googled and searched this Apple forum but all the solutions cannot solve my issue and so I post this thread here. Anybody has any idea that I can track down unknown PC IP?

Thanks.

iMac, Mac OS X (10.7.1), iMac, MacBook Pro, Mac Pro, iPhone, iPad, and more

Posted on Oct 3, 2011 10:16 PM

Reply

Answer 1

Best reply

rkaufmann87

Level 10

140,478 points

Oct 3, 2011 10:46 PM in response to Mr. Latte

No one is getting into your system. This only means you have File Sharing turned on and you can see another computer within range. It probably is a neighbor. If it bothers you can turn off file sharing (System Preferences - Sharing - de-select File Sharing) or you can make it so that Shared items are hidden in Finder. Open a Finder window move your cursor over the Shared items on the left pane then click hide.

Reply

Answer 2

Mr. Latte Author

Level 1

14 points

Oct 3, 2011 11:37 PM in response to rkaufmann87

Hi, Rkaufmann87,

thanks for your suggestion. However, I have 3 iMac's and 1 MBP in the office. They all have File Sharing turned off. They only have Screen Sharing turned on. And all of the Mac can see the unknown PC.

I had never had such problem in Snow Leopard before. Do you think it might be Lion's new feature AirDrop so that I can see other peoples PC despite they are in different workgroup? But if so, I should see all my neighbor office PC....but I don't see them excpet 1 PC.

Thx!

Reply

Answer 3

rkaufmann87

Level 10

140,478 points

Oct 3, 2011 11:45 PM in response to Mr. Latte

This has nothing to do with Air Drop, that only works on Macs and even then not all Mac. Here is Apple's information about Air Drop compatiblity.

AirDrop with my computer?

Again your systems are secure and they can only see there is a PC out there however if file sharing is turned off then you have nothing to worry about. Again if you want to not be able to see the PC in a Finder Window hover the mouse over the left pane where it says "Shared" then click hide and it will no longer be seen. Another (and easier method) is in Finder - Preferences - Sidebar tab - deselect what you don't want seen under Shared.

Reply

Answer 4

Mr. Latte Author

Level 1

14 points

Oct 3, 2011 11:58 PM in response to rkaufmann87

Yet to mention, I have 4 public PC sitting in the office and their names are showing up correctly and as expected. It is just the unknown PC showing up on the sidebar. I am sure I don't have that PC in my office as all my PC are enumerated in alphabetical order.

I prefer not to overlook the unknown PC by just hiding the share menu. I blieve if things are setup correctly, the name should show up correctly.

Thx!

Reply