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上一篇文章介绍了如何通过设置DNS服务器来加速上网体验,今天我要向大家介绍的是如何设置透明代理实现HTTP的缓存,稍后将介绍如何过滤屏蔽相关广告站点。

首先我们已经配置好了无线热点,如果不清楚的话可以 参考我前面的文章 ,配置好的效果是通过无线网卡连接到树莓派,然后流量经过wlan0网卡转到eth0然后出口,也就是说eth0相当于我们路由器的WAN口,而wlan0相当于局域网LAN口,理清这个关系后下面我们继续。

首先要安装squid3,这里可以直接通过下面的命令进行:

apt-get install squid3

之前大家应该记得我设置无线路由功能时使用了下面的iptables配置:

sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT

如果我们已经做了上述配置,那么下面只要再运行一条iptables命令就可以把80端口的流量转到squid3的3128端口了:

iptables -t nat -A PREROUTING -i wlan0 -p tcp --dport 80 -j REDIRECT --to-ports 3128

替换之前我们设置的 iptables.ipv4.nat ,当然先备份一下:

sudo mv /etc/iptables.ipv4.nat /etc/iptables.ipv4.nat.old
sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

做完上述命令后你会发现现在所有的网页都出现了squid的默认拒绝访问的画面,说明squid3已经开始工作了,下面我们需要对其进行配置,参考如下的patch编辑配置文件 /etc/squid3/squid.conf

-- /etc/squid3/squid.conf.orig 2013-02-25 11:31:23.839560066 +1300
+++ /etc/squid3/squid.conf      2013-02-26 09:07:15.388951441 +1300
@@ -702,6 +702,7 @@
 #acl localnet src 192.168.0.0/16       # RFC1918 possible internal network
 #acl localnet src fc00::/7       # RFC 4193 local private network range
 #acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) machines
+acl localnet src 192.168.42.0/24
 
 acl SSL_ports port 443
 acl Safe_ports port 80         # http
@@ -828,7 +829,7 @@
 # We strongly recommend the following be uncommented to protect innocent
 # web applications running on the proxy server who think the only
 # one who can access services on "localhost" is a local user
-#http_access deny to_localhost
+http_access deny to_localhost
 
 #
 # INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
@@ -837,7 +838,7 @@
 # Example rule allowing access from your local networks.
 # Adapt localnet in the ACL section to list your (internal) IP networks
 # from where browsing should be allowed
-#http_access allow localnet
+http_access allow localnet
 http_access allow localhost
 
 # And finally deny all other access to this proxy
@@ -1133,7 +1134,7 @@
 #
 
 # Squid normally listens to port 3128
-http_port 3128
+http_port 3128 intercept
 
 #  TAG: https_port
 # Note: This option is only available if Squid is rebuilt with the
@@ -2073,7 +2074,7 @@
 #      accessed frequently in memory to improve performance whilst low
 #      enough to keep larger objects from hoarding cache_mem.
 #Default:
-# maximum_object_size_in_memory 512 KB
+maximum_object_size 128000 KB
 
 #  TAG: memory_replacement_policy
 #      The memory replacement policy parameter determines which
@@ -2229,7 +2230,7 @@
 #
 
 # Uncomment and adjust the following to add a disk cache directory.
-#cache_dir ufs /var/spool/squid3 100 16 256
+cache_dir ufs /var/spool/squid3 1000 16 256
 
 #  TAG: store_dir_select_algorithm
 #      Set this to 'round-robin' as an alternative.
@@ -2611,7 +2612,7 @@
 #      Note2, for Debian/Linux the default of logfile_rotate is
 #      zero, since it includes external logfile-rotation methods.
 #Default:
-# logfile_rotate 0
+logfile_rotate 10
 
 #  TAG: emulate_httpd_log      on|off
 #      The Cache can emulate the log file format which many 'httpd'
@@ -3673,7 +3674,7 @@
 #      during shutdown mode.  Any active clients after this many
 #      seconds will receive a 'timeout' message.
 #Default:
-# shutdown_lifetime 30 seconds
+shutdown_lifetime 2 seconds
 
 # ADMINISTRATIVE PARAMETERS
 # -----------------------------------------------------------------------------

注意这里 maximum_object_size ,由于我通过 free -m 查看发觉内存已经被消耗了200多M了,所以综合考虑我让squid3再用128M作为内存缓存用; cache_dir ufs /var/spool/squid3 1000 16 256 根据个人情况设置,我根据存储卡大小设置为1000,也就是1GB。

设置完成后通过 squid3 -k parse 检查一下有没有错误,没有错误的话直接通过 squid3 -k reconfigure 加载配置。

现在可以正常浏览网页了吧?

下面讲解如何屏蔽广告站点,首先还是编辑squid3的配置文件 /etc/squid3/squid.conf ,添加如下内容:

## disable ads ( http://pgl.yoyo.org/adservers/ )
acl ads dstdom_regex "/etc/squid/ad_block.txt"
http_access deny ads
#deny_info TCP_RESET ads

建立广告列表更新脚本 ad_servers_newlist.sh

#### Calomel.org  ad_servers_newlist.sh 
#
## get new ad server list
wget -O /etc/squid3/ad_block.txt 'http://pgl.yoyo.org/adservers/serverlist.php?hostformat=squid-dstdom-regex&showintro=0&mimetype=plaintext'

## refresh squid
/usr/sbin/squid3 -k reconfigure

具体的被屏蔽的广告列表见 这里 ,好了,下面需要运行一下这个脚本:

sudo sh ad_servers_newlist.sh

然后任意访问刚才广告列表中列出的网址,看看是不是被squid3拦截了?

参考文档:

2013年12月9日更新

今天在树莓上架设了Web服务器,然后发现在eth0没有联网的情况下,访问这个Web服务会异常缓慢,于是决定改写上面的iptables规则,假设树莓主机wlan0的IP地址是192.168.43.1,我们可以让所有访问这个地址的不进行转发,最终的规则整理如下,当然在操作前建议使用 sudo iptables -t nat -F 清空先前的设定:

sudo iptables -t nat  -A PREROUTING -i wlan0 -p tcp -d 192.168.43.1 --dport 80 -j ACCEPT
sudo iptables -t nat -A PREROUTING -i wlan0 -p tcp --dport 80 -j REDIRECT --to-ports 3128
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT