Linux-Squid代理服务器
一.Squid的简介
Squid是一个支持HTTP HTTPS FTP等服务的Web缓存代理服务，可以通过缓存页面实现降低带宽占用并优化页面响应时间。此外，Squid还具有强大的访问功能。
Squid代码请求流程为：客户端访问Squid代理服务器，由代理服务器代表客户访问后端真实服务器，真实服务器将响应数据返回给代理服务器，代理服务器将数据返回给客户，同时将页面缓存到本地内存及硬盘中，当下次客户端再有响应要求时，代理服务器将直接从本地缓存中提取数据返回给客户端。
代理服务器有多种类型，一般意义上常分为标准正向代理服务器 透明代理服务器 反向代理服务器
二.Squid的正向代理
正向代理：代理服务器位于客户端和真实服务器之间的服务器，为了从真实服务器取得内容，客户端向代理发送一个请求并指定目标(真实服务器)，然后代理向真实服务器转交请求并将获得的内容返回给客户端。客户端才能使用正向代理。
客户端主动寻找代理服务器，为了通过代理服务器访问自己本身无法直接访问的主机，客户端借由正向代理可以间接访问很多不同互联网服务器的资源
正向代理作为客户端的代理，将从互联网上获取的资源返回给一个或多个的客户端，服务端（如Web服务器）只知道代理的IP地址而不知道客户端的IP地址。
实验前提：两台虚拟机，一台有网作为真实服务器，一台没网作为客户端
1.服务端虚拟主机的设定
（1）设置网络保证有网，火墙处于开启状态
[root@localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
TYPE=Ethernet
BOOTPROTO=none
DEVICE=eth0
ONBOOT=yes
DNS1=114.114.114.114
IPADDR=172.25.4.105 ##ip
PREFIX=24 ##子网掩码
GATEWAY=172.25.4.250 ##网关
[root@localhost ~]# systemctl status firewalld.service
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: active (running) since Sat 2019-05-04 22:12:28 CST; 38min ago
Docs: man:firewalld(1) ##火墙开启状态
Main PID: 4337 (firewalld)
CGroup: /system.slice/firewalld.service
└─4337 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
May 04 22:12:28 localhost.localdomain systemd[1]: Starting firewalld - dynami...
May 04 22:12:28 localhost.localdomain systemd[1]: Started firewalld - dynamic...
May 04 22:23:47 localhost.localdomain firewalld[4337]: ERROR: UNKNOWN_INTERFA...
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# ping www.baidu.com ##验证网络正常
PING www.a.shifen.com (183.232.231.172) 56(84) bytes of data.
64 bytes from 183.232.231.172 (183.232.231.172): icmp_seq=1 ttl=53 time=59.7 ms
64 bytes from 183.232.231.172 (183.232.231.172): icmp_seq=2 ttl=53 time=67.5 ms
64 bytes from 183.232.231.172 (183.232.231.172): icmp_seq=3 ttl=53 time=76.4 ms
64 bytes from 183.232.231.172 (183.232.231.172): icmp_seq=4 ttl=53 time=83.9 ms
（2）Squid服务器的安装
[root@localhost ~]# yum install squid -y
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-
: manager
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
westos | 4.1 kB 00:00
Resolving Dependencies
--> Running transaction check
---> Package squid.x86_64 7:3.5.20-2.el7 will be installed
--> Processing Dependency: perl(Digest::MD5) for package: 7:squid-3.5.20-2.el7.x86_64
--> Processing Dependency: squid-migration-script for package: 7:squid-3.5.20-2.el7.x86_64
--> Processing Dependency: libecap.so.3()(64bit) for package: 7:squid-3.5.20-2.el7.x86_64
--> Running transaction check
---> Package libecap.x86_64 0:1.0.0-1.el7 will be installed
---> Package perl-Digest-MD5.x86_64 0:2.52-3.el7 will be installed
--> Processing Dependency: perl(Digest::base) >= 1.00 for package: perl-Digest-MD5-2.52-3.el7.x86_64
---> Package squid-migration-script.x86_64 7:3.5.20-2.el7 will be installed
--> Running transaction check
---> Package perl-Digest.noarch 0:1.17-245.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
squid x86_64 7:3.5.20-2.el7 westos 3.0 M
Installing for dependencies:
libecap x86_64 1.0.0-1.el7 westos 21 k
perl-Digest noarch 1.17-245.el7 westos 23 k
perl-Digest-MD5 x86_64 2.52-3.el7 westos 30 k
squid-migration-script x86_64 7:3.5.20-2.el7 westos 47 k
Transaction Summary
================================================================================
Install 1 Package (+4 Dependent packages)
Total download size: 3.1 M
Installed size: 10 M
Downloading packages:
--------------------------------------------------------------------------------
Total 17 MB/s | 3.1 MB 00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : 7:squid-migration-script-3.5.20-2.el7.x86_64 1/5
Installing : libecap-1.0.0-1.el7.x86_64 2/5
Installing : perl-Digest-1.17-245.el7.noarch 3/5
Installing : perl-Digest-MD5-2.52-3.el7.x86_64 4/5
Installing : 7:squid-3.5.20-2.el7.x86_64 5/5
Verifying : 7:squid-3.5.20-2.el7.x86_64 1/5
Verifying : perl-Digest-1.17-245.el7.noarch 2/5
Verifying : perl-Digest-MD5-2.52-3.el7.x86_64 3/5
Verifying : libecap-1.0.0-1.el7.x86_64 4/5
Verifying : 7:squid-migration-script-3.5.20-2.el7.x86_64 5/5
Installed:
squid.x86_64 7:3.5.20-2.el7
Dependency Installed:
libecap.x86_64 0:1.0.0-1.el7
perl-Digest.noarch 0:1.17-245.el7
perl-Digest-MD5.x86_64 0:2.52-3.el7
squid-migration-script.x86_64 7:3.5.20-2.el7
Complete!
[root@localhost ~]# systemctl start squid
（3）Squid服务器的设置
[root@localhost ~]# netstat -antlupe | grep squid ##查看squid服务端口为3128
tcp6 0 0 :::3128 :::* LISTEN 0 80808 7627/(squid-1)
udp 0 0 0.0.0.0:37751 0.0.0.0:* 23 80805 7627/(squid-1)
udp6 0 0 :::56003 :::* 23 80804 7627/(squid-1)
[root@localhost ~]# firewall-cmd --add-port=3128/tcp ##火墙添加3128端口
success
[root@localhost ~]# firewall-cmd --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: dhcpv6-client ftp http ssh
ports: 443/tcp 3128/tcp ##添加成功
protocols:
masquerade: no
forward-ports:
sourceports:
icmp-blocks:
rich rules:
[root@localhost ~]# vim /etc/squid/squid.conf ##编辑squid主配置文件
[root@localhost ~]# ll /var/spool/squid/ ##此目录用于存放缓存文件，此时无缓存文件
total 0
[root@localhost ~]# systemctl restart squid.service ##重启服务
[root@localhost ~]# ll /var/spool/squid/ ##缓存文件出现
total 196
drwxr-x---. 258 squid squid 8192 May 4 23:02 00
drwxr-x---. 258 squid squid 8192 May 4 23:02 01
drwxr-x---. 258 squid squid 8192 May 4 23:02 02
drwxr-x---. 258 squid squid 8192 May 4 23:02 03
drwxr-x---. 258 squid squid 8192 May 4 23:02 04
drwxr-x---. 258 squid squid 8192 May 4 23:02 05
drwxr-x---. 258 squid squid 8192 May 4 23:02 06
drwxr-x---. 258 squid squid 8192 May 4 23:02 07
drwxr-x---. 258 squid squid 8192 May 4 23:02 08
drwxr-x---. 258 squid squid 8192 May 4 23:02 09
drwxr-x---. 258 squid squid 8192 May 4 23:02 0A
drwxr-x---. 258 squid squid 8192 May 4 23:02 0B
drwxr-x---. 258 squid squid 8192 May 4 23:02 0C
drwxr-x---. 258 squid squid 8192 May 4 23:02 0D
drwxr-x---. 258 squid squid 8192 May 4 23:02 0E
drwxr-x---. 258 squid squid 8192 May 4 23:02 0F
-rw-r-----. 1 squid squid 72 May 4 23:02 swap.state
2.客户端虚拟主机的设定
[root@localhost ~]# ping www.baidu.com
ping: unknown host www.baidu.com
[root@localhost ~]# ping 114.114.114
connect: Network is unreachable
浏览器端测试及设定
三.Squid的反向代理
反向代理是服务器根据客户端的请求，从其关系的一组或多组后端服务器上获取资源，然后再将这些资源返回给客户端，客户端只会得知反向代理的IP地址，而不知道在代理服务器后面的服务器簇的存在
反向代理是作为服务器端（如Web服务器）的代理使用，反向代理是供很多客户端都通过它间接访问不同后端服务器上的资源，而不需要知道这些后端服务器的存在，而以为所有资源都来自于这个反向代理服务器。
企业自己进行设置 让客户进行访问时候访问代理服务器看到资源服务器的东西，代理服务器中并没有资源
实验前提：三台主机
1.服务器端：有http 无squid并且关闭火墙
2.代理端 无http 有squid
3.客户端进行测试
服务端的设置：172.25.4.104
[root@localhost ~]# systemctl stop firewalld.service ##关闭火墙
[root@localhost ~]# systemctl status firewalld.service ##查看火墙状态
firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
Active: inactive (dead) since Sat 2019-05-04 12:25:38 EDT; 10s ago
Main PID: 498 (code=exited, status=0/SUCCESS)
May 04 12:15:35 localhost systemd[1]: Started firewalld - dynamic firewall ...n.
May 04 12:25:38 localhost systemd[1]: Stopping firewalld - dynamic firewall.....
May 04 12:25:38 localhost systemd[1]: Stopped firewalld - dynamic firewall ...n.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# yum install httpd -y
Loaded plugins: langpacks
Resolving Dependencies
--> Running transaction check
---> Package httpd.x86_64 0:2.4.6-45.el7 will be installed
--> Processing Dependency: httpd-tools = 2.4.6-45.el7 for package: httpd-2.4.6-45.el7.x86_64
--> Processing Dependency: /etc/mime.types for package: httpd-2.4.6-45.el7.x86_64
--> Processing Dependency: libapr-1.so.0()(64bit) for package: httpd-2.4.6-45.el7.x86_64
--> Processing Dependency: libaprutil-1.so.0()(64bit) for package: httpd-2.4.6-45.el7.x86_64
--> Running transaction check
---> Package apr.x86_64 0:1.4.8-3.el7 will be installed
---> Package apr-util.x86_64 0:1.5.2-6.el7 will be installed
---> Package httpd-tools.x86_64 0:2.4.6-45.el7 will be installed
---> Package mailcap.noarch 0:2.1.41-2.el7 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
httpd x86_64 2.4.6-45.el7 westos 1.2 M
Installing for dependencies:
apr x86_64 1.4.8-3.el7 westos 103 k
apr-util x86_64 1.5.2-6.el7 westos 92 k
httpd-tools x86_64 2.4.6-45.el7 westos 84 k
mailcap noarch 2.1.41-2.el7 westos 31 k
Transaction Summary
================================================================================
Install 1 Package (+4 Dependent packages)
Total download size: 1.5 M
Installed size: 4.3 M
Downloading packages:
--------------------------------------------------------------------------------
Total 9.0 MB/s | 1.5 MB 00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : apr-1.4.8-3.el7.x86_64 1/5
Installing : apr-util-1.5.2-6.el7.x86_64 2/5
Installing : httpd-tools-2.4.6-45.el7.x86_64 3/5
Installing : mailcap-2.1.41-2.el7.noarch 4/5
Installing : httpd-2.4.6-45.el7.x86_64 5/5
Verifying : httpd-tools-2.4.6-45.el7.x86_64 1/5
Verifying : apr-util-1.5.2-6.el7.x86_64 2/5
Verifying : mailcap-2.1.41-2.el7.noarch 3/5
Verifying : httpd-2.4.6-45.el7.x86_64 4/5
Verifying : apr-1.4.8-3.el7.x86_64 5/5
Installed:
httpd.x86_64 0:2.4.6-45.el7
Dependency Installed:
apr.x86_64 0:1.4.8-3.el7 apr-util.x86_64 0:1.5.2-6.el7
httpd-tools.x86_64 0:2.4.6-45.el7 mailcap.noarch 0:2.1.41-2.el7
Complete!
[root@localhost ~]# systemctl stop firewalld.service
[root@localhost ~]# systemctl status firewalld.service
firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled)
Active: inactive (dead) since Sat 2019-05-04 12:25:38 EDT; 10s ago
Main PID: 498 (code=exited, status=0/SUCCESS)
May 04 12:15:35 localhost systemd[1]: Started firewalld - dynamic firewall ...n.
May 04 12:25:38 localhost systemd[1]: Stopping firewalld - dynamic firewall.....
May 04 12:25:38 localhost systemd[1]: Stopped firewalld - dynamic firewall ...n.
Hint: Some lines were ellipsized, use -l to show in full.
[root@localhost ~]# cd /var/www/html/
[root@localhost html]# ls
[root@localhost html]# vim index.html
[root@localhost html]# cat index.html
www.shenzhen.com
[root@localhost html]# systemctl restart httpd
[root@localhost html]# systemctl enable httpd
ln -s '/usr/lib/systemd/system/httpd.service' '/etc/systemd/system/multi-user.target.wants/httpd.service'
代理端设置：172.25.4.105
[root@localhost ~]# firewall-cmd --permanent --add-port=80/tcp ##添加80端口
success
[root@localhost ~]# firewall-cmd --reload
success
[root@localhost ~]# firewall-cmd --list-all
public (active)
target: default
icmp-block-inversion: no
interfaces: eth0
sources:
services: dhcpv6-client ftp http ssh
ports: 443/tcp 3128/tcp 80/tcp
protocols:
masquerade: no
forward-ports:
sourceports:
icmp-blocks:
rich rules:
[root@ftp_server ~]# vim /etc/squid/squid.conf ##编辑主配置文件
[root@ftp_server ~]# systemctl restart squid
59 http_port 80 vhost vport ##允许通过的端口为80，80为虚拟化端口
60 cache_peer 172.25.254.205 parent 80 0 proxy-only ##80端口仅作代理
客户端的测试：输入代理端ip看是否能得到服务端内容
