$ sudo a2enmod proxy_http

client denied by server configuration: proxy:http://localhost:81/aipo/

$ sudo vim /etc/apache2/mods-enabled/proxy.conf

AddDefaultCharset off

Order deny,allow

Deny from all

#Allow from .example.com

Allow from all

$ sudo vim /etc/apache2/sites-available/default

​P​r​o​x​y​P​r​e​s​e​r​v​e​H​o​s​t​ ​ ​ ​O​n​

​​P​r​o​x​y​P​a​s​s​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​/​a​i​p​o​/​ ​ ​ ​ ​ ​ h​t​t​p​:​/​/​l​o​c​a​l​h​o​s​t​:​8​1​/​a​i​p​o​/

​​P​r​o​x​y​P​a​s​s​R​e​v​e​r​s​e​ ​ ​ ​ ​/​a​i​p​o​/​ ​ ​ ​ ​ ​ h​t​t​p​:​/​/​l​o​c​a​l​h​o​s​t​:​8​1​/​a​i​p​o​/

$ sudo /etc/init.d/apache2 restart