Why can't I access Google and other sites when tethering my phone? When I tether my phone, I can't access Google or Gmail (other sites, too [see below]!). 

cmd: ping http://www.google.com; Ping request could not find host...




List of problem sites/applications:

    Sites:

http://www.google.com; http://www.google.co.jp; https://encrypted.google.com.
http://www.gmail.com.

http://search.yahoo.com, same issue.

Also, http://play.google.com. 

Further, https://github.com.

Dang!  https://www.freelancer.com.

http://www.sugarsync.com.

http://www.dropbox.com.

Parts of http://www.titanpad.com (i.e., login); makes me curious as to whether or not it's a language-blocking issue....

    Apps:

ET Naver Line (a.k.a. LINE) jp.naver.android.npush

I experience this on various sites and apps; however the above are sites tested as working over emobile (separate modem)--the URLs should be correct.  I would change the question title, but I have a support request in with the developers to contact me via this site for a resolution.



Device info:

    Phones:

 - Softbank Fujitsu Arrows 301F; 4.1-Jelly Bean.
 - Softbank Aquos 104SH; 4.0-Icecream Sandwich.
 - Connected via USB, debugging mode enabled, in MTP mode.
 - Phone's DNS: Google DNS; OpenDNS.
    PC's:

 - PC OS: Windows 7 SP 1 (please request any hardware specs).
 - Connection methods tested: chrome latest, IE10 latest, cmd (ping), telnet.
 - PC's DNS: OpenDNS; Google DNS; no DNS.
    Non-specific:

 - Tethering software: easytether lite (no root).



Known error messages:

Via Chrome:


  This webpage is not available
  
  Reload  Less Google Chrome could not load the webpage because
  www.google.co.jp took too long to respond. The website may be down, or
  you may be experiencing issues with your Internet connection. Check
  your Internet connection. Check any cables and reboot any routers,
  modems, or other network devices you may be using. Allow Chrome to
  access the network in your firewall or antivirus settings. If it is
  already listed as a program allowed to access the network, try
  removing it from the list and adding it again. If you use a proxy
  server... Check your proxy settings or contact your network
  administrator to make sure the proxy server is working. If you don't
  believe you should be using a proxy server: Go to the Chrome menu >
  Settings > Show advanced settings... > Change proxy settings... > LAN
  Settings and deselect "Use a proxy server for your LAN". Error code:
  ERR_CONNECTION_TIMED_OUT


Via IE 10:

Via CMD: 


  Ping request could not find host http://www.google.com. Please check
  the name and try again.


Via Telnet:

Connecting To http://www.google.com...Could not open connection to the host, on port 23: Connect failed

Via LINE: 


  Unable to login due to network issues.  Please check your connection
  and try again.




Question summary:

Why am I experiencing these issues (not being able to connect to the above-mentioned websites), and how can these issues be resolved?  Can you help me test what I think is causing the issues?



Proposed causes:


Perhaps the reason I cannot access these sites is because they are in use by the phone?  If that is the case, I am not sure how to
test it.  So far, when I "force-stop" and "disable" an app like
LINE, I still cannot connect.  So, I thought: it's possible that
the phone is reserving the app's networking info, somehow.  So, I went so far as to uninstall Line from my phone and reset the phone
and PC.  Still unable to use Line on the PC.  Furthermore; Skype
works simultaneously on PC and Phone.
Perhaps it's a PC or OS issue?  I still have yet to tether my phones to a different PC or OS.
Perhaps it's a DNS issue?  I still have yet to test this, but I believe I get a similar error with OpenDNS when trying to access localhost.
"Activate EasyTether or use it with UDP and secure sites BLOCKED?  This message appears at the top of Easy Tether's settings screen.  I'm very curious to know whether or not this is the cause.  It seems highly likely.
Resolution

EasyTether Light (No Root) is the best tethering software I've been able to find on the Play store; however, it blocks UDP ports and secure protocols.  Updating to EasyTether Full (cost: 9.99 USD) resolved the issues on all of the above-listed sites and services.  It was very bothersome to go through all this and e-mail the developer, only to get a kind of boggled response from him.  Their FAQ does not mention this, and the message in the app was covered up by the "warning, do not scratch the camera" message I had written on my screen guard, up until yesterday; so, I simply didn't notice.  I hope the developer will upgrade the app to include some kind of pop-up message indicating that this is the cause of the issue, or at least add the issue to the FAQ.

Thanks for all the comments and wonderful help!