刚解决了一个问题，快速更新一下。当虚拟主机无法获得DHCP IP地址时，应该做的第一件事情是检查防火墙，无论是Windows防火墙或者物理防火墙。UDP端口67和68不能被阻挡掉。否则会出现虚拟主机只能获得169.x.x.x的IP地址，这个地址是不可用的，表示虚拟主机无法从DHCP服务器获得地址。
这两个端口是DHCP客户端用来从DHCP服务器获取IP地址的。具体的技术细节可以参考RFC文档。
DHCP uses UDP as its transport protocol. DHCP messages from a client
to a server are sent to the ‘DHCP server’ port (67), and DHCP
messages from a server to a client are sent to the ‘DHCP client’ port
(68). A server with multiple network address (e.g., a multi-homed
host) MAY use any of its network addresses in outgoing DHCP messages.
我在排错过程中也用到了这篇文章。