Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

时间:2023-12-14 09:41:56

          Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

                                                作者:尹正杰

版权声明:原创作品,谢绝转载!否则将追究法律责任。

一.虚拟主机实现方案

1>.Apache httpd 有三种实现虚拟主机的方案

  基于ip:
    为每个虚拟主机准备至少一个ip地址
  基于port:
    为每个虚拟主机使用至少一个独立的port
  基于FQDN:
    为每个虚拟主机使用至少一个FQDN

2>.创建测试网页文件

[root@node101.yinzhengjie.org.cn ~]# mkdir /var/www/html/{a,b,c}site
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# echo "<h1>www.a.com</h1>" > /var/www/html/asite/index.html
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# echo "<h1>www.b.org</h1>" > /var/www/html/bsite/index.html
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# echo "<h1>www.c.net</h1>" > /var/www/html/csite/index.html
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /var/www/html/asite/index.html
<h1>www.a.com</h1>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /var/www/html/bsite/index.html
<h1>www.b.org</h1>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /var/www/html/csite/index.html
<h1>www.c.net</h1>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

二.基于不同的IP地址实现虚拟主机配置实战案例

1>.给一块网卡临时配置多个IP地址测试使用

[root@node101.yinzhengjie.org.cn ~]# ifconfig
eth0: flags=<UP,BROADCAST,RUNNING,MULTICAST> mtu
inet 10.0.2.15 netmask 255.255.255.0 broadcast 10.0.2.255
ether :::e0:bb: txqueuelen (Ethernet)
RX packets bytes (2.0 KiB)
RX errors dropped overruns frame
TX packets bytes (1.5 KiB)
TX errors dropped overruns carrier collisions eth1: flags=<UP,BROADCAST,RUNNING,MULTICAST> mtu
inet 172.30.1.101 netmask 255.255.255.0 broadcast 172.30.1.255
ether :::c1:c7: txqueuelen (Ethernet)
RX packets bytes (1.6 MiB)
RX errors dropped overruns frame
TX packets bytes (2.0 MiB)
TX errors dropped overruns carrier collisions lo: flags=<UP,LOOPBACK,RUNNING> mtu
inet 127.0.0.1 netmask 255.0.0.0
loop txqueuelen (Local Loopback)
RX packets bytes (15.2 KiB)
RX errors dropped overruns frame
TX packets bytes (15.2 KiB)
TX errors dropped overruns carrier collisions [root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ip addr a 172.30.1.200 dev eth1
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ip addr a 172.30.1.100 dev eth1
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ip a
: lo: <LOOPBACK,UP,LOWER_UP> mtu qdisc noqueue state UNKNOWN group default qlen
link/loopback ::::: brd :::::
inet 127.0.0.1/ scope host lo
valid_lft forever preferred_lft forever
: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu qdisc pfifo_fast state UP group default qlen
link/ether :::e0:bb: brd ff:ff:ff:ff:ff:ff
inet 10.0.2.15/ brd 10.0.2.255 scope global noprefixroute dynamic eth0
valid_lft 79421sec preferred_lft 79421sec
: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu qdisc pfifo_fast state UP group default qlen
link/ether :::c1:c7: brd ff:ff:ff:ff:ff:ff
inet 172.30.1.101/ brd 172.30.1.255 scope global noprefixroute eth1
valid_lft forever preferred_lft forever
inet 172.30.1.200/ scope global eth1
valid_lft forever preferred_lft forever
inet 172.30.1.100/ scope global eth1
valid_lft forever preferred_lft forever
[root@node101.yinzhengjie.org.cn ~]#

Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

2>.编辑httpd的配置文件

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf
ServerRoot "/etc/httpd"
Listen
Include conf.modules.d/*.conf
User apache
Group apache
ServerAdmin root@localhost
<Directory />
AllowOverride none
Require all denied
</Directory>
DocumentRoot "/var/www/html"
<Directory "/var/www">
AllowOverride None
Require all granted
</Directory>
<Directory "/var/www/html">
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>
<Files ".ht*">
Require all denied
</Files>
ErrorLog "logs/error_log"
LogLevel warn
<IfModule log_config_module>
LogFormat "%h %l %u %{%Y-%m-%d %H:%M:%S}t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" testlog
LogFormat "%h %l %u %t \"%r\" %>s %b" common
<IfModule logio_module>
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
</IfModule>
CustomLog "logs/access_log" testlog
</IfModule>
<IfModule alias_module>
ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
</IfModule>
<Directory "/var/www/cgi-bin">
AllowOverride None
Options None
Require all granted
</Directory>
<IfModule mime_module>
TypesConfig /etc/mime.types
AddType application/x-compress .Z
AddType application/x-gzip .gz .tgz
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
</IfModule>
AddDefaultCharset UTF-8
<IfModule mime_magic_module>
MIMEMagicFile conf/magic
</IfModule>
EnableSendfile on
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf      #查看主配置文件内容

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf  | grep ServerRoot
ServerRoot "/etc/httpd"
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf | grep IncludeOptional
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /etc/httpd/conf.d/virtualHost.conf
<VirtualHost "172.30.1.100:80">
DocumentRoot "/var/www/html/asite"
<Directory "/var/www/html/asite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_asite_log" testlog        #注意这个testlog变量需要在主配置文件中定义哟~
</VirtualHost> <VirtualHost "172.30.1.101:80">
DocumentRoot "/var/www/html/bsite"
<Directory "/var/www/html/bsite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_bsite_log" testlog
</VirtualHost> <VirtualHost "172.30.1.200:80">
DocumentRoot "/var/www/html/csite"
<Directory "/var/www/html/csite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_csite_log" testlog
</VirtualHost>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# httpd -t
Syntax OK
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# systemctl reload httpd
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ss -ntl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:80 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 128 :::22 :::*
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

3>.验证客户端是否可以正常访问

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_asite_log
172.30.1.100 - - -- :: "GET / HTTP/1.1" "-" "curl/7.29.0"
172.30.1.254 - - -- :: "GET / HTTP/1.1" "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebK
it/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"172.30.1.254 - - 2019-12-09 16:01:24 "GET /favicon.ico HTTP/1.1" 404 209 "http://172.30.1.100/" "Mozilla/5.0 (Windows
NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_asite_log

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_bsite_log
172.30.1.101 - - -- :: "GET / HTTP/1.1" "-" "curl/7.29.0"
172.30.1.254 - - -- :: "GET / HTTP/1.1" "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebK
it/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"172.30.1.254 - - 2019-12-09 16:02:25 "-" 408 - "-" "-"
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_bsite_log

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_csite_log
172.30.1.200 - - -- :: "GET / HTTP/1.1" "-" "curl/7.29.0"
172.30.1.254 - - -- :: "GET / HTTP/1.1" "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebK
it/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"172.30.1.254 - - 2019-12-09 16:01:39 "GET /favicon.ico HTTP/1.1" 404 209 "http://172.30.1.200/" "Mozilla/5.0 (Windows
NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36"172.30.1.254 - - 2019-12-09 16:02:31 "-" 408 - "-" "-"
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# tail /var/log/httpd/access_csite_log

Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

三.基于相同IP地址的不同端口实现虚拟主机配置实战案例

1>.编辑httpd的配置文件

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf
ServerRoot "/etc/httpd"
Listen
Include conf.modules.d/*.conf
User apache
Group apache
ServerAdmin root@localhost
<Directory />
AllowOverride none
Require all denied
</Directory>
DocumentRoot "/var/www/html"
<Directory "/var/www">
AllowOverride None
Require all granted
</Directory>
<Directory "/var/www/html">
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>
<Files ".ht*">
Require all denied
</Files>
ErrorLog "logs/error_log"
LogLevel warn
<IfModule log_config_module>
LogFormat "%h %l %u %{%Y-%m-%d %H:%M:%S}t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" testlog
LogFormat "%h %l %u %t \"%r\" %>s %b" common
<IfModule logio_module>
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
</IfModule>
CustomLog "logs/access_log" testlog
</IfModule>
<IfModule alias_module>
ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
</IfModule>
<Directory "/var/www/cgi-bin">
AllowOverride None
Options None
Require all granted
</Directory>
<IfModule mime_module>
TypesConfig /etc/mime.types
AddType application/x-compress .Z
AddType application/x-gzip .gz .tgz
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
</IfModule>
AddDefaultCharset UTF-8
<IfModule mime_magic_module>
MIMEMagicFile conf/magic
</IfModule>
EnableSendfile on
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf      #查看主配置文件内容

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf  | grep ServerRoot
.ServerRoot "/etc/httpd"
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf | grep IncludeOptional
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /etc/httpd/conf.d/virtualHost.conf
Listen 8080          #注意,千万别忘记监听不同的端口哟~
Listen 8081
Listen 8082 <VirtualHost "*:8080">
DocumentRoot "/var/www/html/asite"
<Directory "/var/www/html/asite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_asite_log" testlog
</VirtualHost> <VirtualHost "*:8081">
DocumentRoot "/var/www/html/bsite"
<Directory "/var/www/html/bsite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_bsite_log" testlog
</VirtualHost> <VirtualHost "*:8082">
DocumentRoot "/var/www/html/csite"
<Directory "/var/www/html/csite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_csite_log" testlog
</VirtualHost>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# httpd -t
Syntax OK
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# systemctl reload httpd
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ss -ntl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:8080 *:*
LISTEN 0 128 *:80 *:*
LISTEN 0 128 *:8081 *:*
LISTEN 0 128 *:8082 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 128 :::22 :::*
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

2>.验证客户端是否可以正常访问

Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

四.基于FQDN实现虚拟主机配置实战案例

1>.配置hosts文件解析

[root@node101.yinzhengjie.org.cn ~]# hostname
node101.yinzhengjie.org.cn
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# hostname -i
172.30.1.101
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# grep 172.30.1.101 /etc/hosts          #添加咱们要配置的虚拟主机FQDN解析,我这里是实验环境添加本地解析即可,生产环境需要添加DNS解析哟~
172.30.1.101 node101.yinzhengjie.org.cn www.a.com www.b.org www.c.net
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ping www.a.com
PING node101.yinzhengjie.org.cn (172.30.1.101) () bytes of data.
bytes from node101.yinzhengjie.org.cn (172.30.1.101): icmp_seq= ttl= time=0.011 ms
^C
--- node101.yinzhengjie.org.cn ping statistics ---
packets transmitted, received, % packet loss, time 0ms
rtt min/avg/max/mdev = 0.011/0.011/0.011/0.000 ms
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# ping www.a.com

[root@node101.yinzhengjie.org.cn ~]# ping www.b.org
PING node101.yinzhengjie.org.cn (172.30.1.101) () bytes of data.
bytes from node101.yinzhengjie.org.cn (172.30.1.101): icmp_seq= ttl= time=0.010 ms
^C
--- node101.yinzhengjie.org.cn ping statistics ---
packets transmitted, received, % packet loss, time 0ms
rtt min/avg/max/mdev = 0.010/0.010/0.010/0.000 ms
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# ping www.b.org

[root@node101.yinzhengjie.org.cn ~]# ping www.c.net
PING node101.yinzhengjie.org.cn (172.30.1.101) () bytes of data.
bytes from node101.yinzhengjie.org.cn (172.30.1.101): icmp_seq= ttl= time=0.015 ms
^C
--- node101.yinzhengjie.org.cn ping statistics ---
packets transmitted, received, % packet loss, time 0ms
rtt min/avg/max/mdev = 0.015/0.015/0.015/0.000 ms
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# ping www.c.net

2>.修改httpd的配置文件

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf
ServerRoot "/etc/httpd"
Listen
Include conf.modules.d/*.conf
User apache
Group apache
ServerAdmin root@localhost
<Directory />
AllowOverride none
Require all denied
</Directory>
DocumentRoot "/var/www/html"
<Directory "/var/www">
AllowOverride None
Require all granted
</Directory>
<Directory "/var/www/html">
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>
<IfModule dir_module>
DirectoryIndex index.html
</IfModule>
<Files ".ht*">
Require all denied
</Files>
ErrorLog "logs/error_log"
LogLevel warn
<IfModule log_config_module>
LogFormat "%h %l %u %{%Y-%m-%d %H:%M:%S}t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" testlog
LogFormat "%h %l %u %t \"%r\" %>s %b" common
<IfModule logio_module>
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
</IfModule>
CustomLog "logs/access_log" testlog
</IfModule>
<IfModule alias_module>
ScriptAlias /cgi-bin/ "/var/www/cgi-bin/"
</IfModule>
<Directory "/var/www/cgi-bin">
AllowOverride None
Options None
Require all granted
</Directory>
<IfModule mime_module>
TypesConfig /etc/mime.types
AddType application/x-compress .Z
AddType application/x-gzip .gz .tgz
AddType text/html .shtml
AddOutputFilter INCLUDES .shtml
</IfModule>
AddDefaultCharset UTF-8
<IfModule mime_magic_module>
MIMEMagicFile conf/magic
</IfModule>
EnableSendfile on
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]#

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf      #查看主配置文件内容

[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf  | grep ServerRoot
ServerRoot "/etc/httpd"
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# egrep -v "^ *#|^$" /etc/httpd/conf/httpd.conf | grep IncludeOptional
IncludeOptional conf.d/*.conf
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# cat /etc/httpd/conf.d/virtualHost.conf
<VirtualHost "*:80">
DocumentRoot "/var/www/html/asite"
ServerName "www.a.com"        #别忘记在这里写上相应的虚拟主机的名称哟~以下配置类似修改即可。
<Directory "/var/www/html/asite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_asite_log" testlog
</VirtualHost> <VirtualHost "*:80">
DocumentRoot "/var/www/html/bsite"
ServerName "www.b.org"
<Directory "/var/www/html/bsite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_bsite_log" testlog
</VirtualHost> <VirtualHost "*:80">
DocumentRoot "/var/www/html/csite"
ServerName "www.c.net"
<Directory "/var/www/html/csite">
Require all granted
</Directory>
CustomLog "/var/log/httpd/access_csite_log" testlog
</VirtualHost>
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# httpd -t
Syntax OK
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# systemctl reload httpd
[root@node101.yinzhengjie.org.cn ~]#
[root@node101.yinzhengjie.org.cn ~]# ss -ntl
State Recv-Q Send-Q Local Address:Port Peer Address:Port
LISTEN 0 128 *:80 *:*
LISTEN 0 128 *:22 *:*
LISTEN 0 128 :::22 :::*
[root@node101.yinzhengjie.org.cn ~]#

3>.如下图所示,编辑windows系统的本地解析文件("C:\Windows\System32\drivers\etc\hosts")

Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

4>.验证客户端是否可以正常访问

Httpd服务入门知识-Httpd服务常见配置案例之虚拟主机

五.总结

  上面我们已经演示了基于IP,端口和FQDN来实现虚拟主机的实战案例,接下来我们分析一下这3种方案的区别。

    基于IP:
      需要使用多个不同的IP地址实现虚拟主机,无疑是会浪费多余的公网IP地址。
  
    基于端口:
      只需要一个公网IP地址即可,并将多个端口的绑定到同一个IP地址上,相对于基于IP实现的虚拟主机要更加节省IP地址,但会占多个端口号实,从而浪费多余的套接字文件。     FQDN:
      基于FQDN只需要一个IP地址和一段端口即可,所有的虚拟主机只绑定在同一个端口即可,不同的虚拟主机根据客户端的请求报文中的"HOST"参数来判断是要访问哪个虚拟主机。如果客户端不指定"HOST"的属性,而是直接输入的是IP地址,则默认使用虚拟主机配置文件中的第一个虚拟主机来进行响应哟~
      基于FQDN实现虚拟主机要比基于IP实现虚拟主机更加节省公网IP地址。
      基于FQDN实现虚拟主机要比基于端口实现虚拟主机更加节省公网IP地址的端口数量。   综上所述,我们生产环境中实现虚拟主机大多数运维人员都会选用基于FQDN的方案实现。