Suppose you have a notebook PC which is configured to use other LAN environments and you want to use your mail user agent on the notebook PC without reconfiguring it.

• 假设你将一台笔记本电脑重新配置成可连入其它的LAN环境,而你不想再重新配置用户邮件代理,即:想直接用原来的配置收发邮件。