在 /etc/apache2/sites-enabled 目录下，应该要存在以下文件：
000-default（默认设定，但是要修改）
abc.com（abc.com网站的设定，这里假定运行2个网站）
def.com（def.com网站的设定，这里假定运行2个网站）
block_ip_access（禁止使用IP地址直接访问apache的默认页）
这是apache的默认内置网站的设置文件。
1，一定要指定只能内部访问，否则当其他人设置其他域名指向你的IP地址，就会引致异常访问和DoS攻击，并且恐怕会有漏洞被利用。
所以要指定内置网站的“域名”，本机用localhost就可以访问，拒绝其他域名：
ServerName localhost
ServerAlias localhost
2，我尝试在其他电脑上修改了hosts，指定“localhost”为这台服务器的IP地址，证实这样也能通过Internet非法访问。
所以要指定除了内部IP地址外，其他地址不能访问：
搜索所有“Allow from all”，
修改为“Deny from all
allow from 127.0.0.0/255.0.0.0 ::1/128”
2个网站的配置文件，唯一要设定的是对应的域名：
ServerName abc.com
ServerAlias www.abc.com
若不设置一个文件来响应直接访问IP地址的访问，就会令访问者可以绕过abc.com、def.com而直接访问到apache的默认内置网站。
所以要指定IP地址禁止访问：
ServerName 公网IP地址
ServerAlias 公网IP地址
并且：
“Allow from all”改为“Deny from all”
最后附上我的四个设定文件，有问题请随时留言，尽复。
ServerAdmin [email protected]
ServerName localhost
ServerAlias localhost
DocumentRoot /var/www
Options FollowSymLinks
AllowOverride all
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Order allow,deny
Deny from all
allow from 127.0.0.0/255.0.0.0 ::1/128
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
AllowOverride all
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
ErrorLog ${APACHE_LOG_DIR}/error.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access.log combined
Alias /doc/ "/usr/share/doc/"
Options Indexes MultiViews FollowSymLinks
AllowOverride all
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
【block_ip_access】
ServerAdmin [email protected]
ServerName 198.74.48.110
ServerAlias 198.74.48.110
DocumentRoot /var/www
Options FollowSymLinks
AllowOverride all
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Order allow,deny
Deny from all
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
AllowOverride all
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Deny from all
ErrorLog ${APACHE_LOG_DIR}/error.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access.log combined
Alias /doc/ "/usr/share/doc/"
Options Indexes MultiViews FollowSymLinks
AllowOverride all
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
【网站1】
ServerAdmin [email protected]
ServerName beec-edu.com
ServerAlias www.beec-edu.com
DocumentRoot /var/www/beec-ifc
Options FollowSymLinks
AllowOverride all
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Order allow,deny
allow from all
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
AllowOverride all
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all
ErrorLog ${APACHE_LOG_DIR}/error.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access.log combined
Alias /doc/ "/usr/share/doc/"
Options Indexes MultiViews FollowSymLinks
AllowOverride all
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128
【网站2】
ServerAdmin [email protected]
ServerName beec-ifc.com
ServerAlias www.beec-ifc.com
DocumentRoot /var/www/beec-ifc
Options FollowSymLinks
AllowOverride all
Options Indexes FollowSymLinks MultiViews
AllowOverride all
Order allow,deny
allow from all
ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
AllowOverride all
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all
ErrorLog ${APACHE_LOG_DIR}/error.log
# Possible values include: debug, info, notice, warn, error, crit,
# alert, emerg.
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access.log combined
Alias /doc/ "/usr/share/doc/"
Options Indexes MultiViews FollowSymLinks
AllowOverride all
Order deny,allow
Deny from all
Allow from 127.0.0.0/255.0.0.0 ::1/128