Linux – Cant get squid proxy to work

i need squid proxy on my centos server. But i just can't get it to work. I did yum install squid. Here is my squid.conf file (i removed all comments):

acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
acl SSL_ports port 443
acl Safe_ports port 80      
acl Safe_ports port 21      
acl Safe_ports port 443     
acl Safe_ports port 70      
acl Safe_ports port 210     
acl Safe_ports port 1025-65535  
acl Safe_ports port 280     
acl Safe_ports port 488     
acl Safe_ports port 591     
acl Safe_ports port 777     
acl CONNECT method CONNECT
acl our_networks src 192.168.1.0/24 192.168.2.0/24
http_access allow our_networks
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
http_access allow localhost
http_access deny all

icp_access allow all

http_port 3128

hierarchy_stoplist cgi-bin ?

access_log /var/log/squid/access.log squid

acl QUERY urlpath_regex cgi-bin \?
cache deny QUERY

refresh_pattern ^ftp:       1440    20% 10080
refresh_pattern ^gopher:    1440    0%  1440
refresh_pattern .       0   20% 4320

acl apache rep_header Server ^Apache
broken_vary_encoding allow apache

coredump_dir /var/spool/squid

Then i just put my server's public ip and port 3128 into my web browsers proxy settings… but it isn't working i can't visit any website. Please help. Thanks.