If you see that your newly created Squid proxy server can’t access Google, Facebook and other sites then you are right place to get the solution. Actually this problem arises when your ISP have no IPV6 for you. And Google,Facebook type giant sites has IPV6. So Squid just route you to access by IPV6 whether you have or not. As you have no IPV6 , you are facing problem.
If you tail to access log , you will see that when you try to access google,facebook or other sites which doesn’t load, is actually trying to connect by IPV6.
tail -f /var/log/squid3/access.log
You need to edit configuration below.
Put below line in the top of the config and save.
This above line just a rule which will force squid to access IPV4 first instead of IPV6. Now restart squid server and you will be able to access those sites now.
service squid3 restart