******21/03/2017 9:05:41 PM******
dhcp_start(netif=20005fe0) en0
dhcp_start(): starting new DHCP client
dhcp_start(): allocated dhcpdhcp_start(): starting DHCP configuration
dhcp_discover()
transaction id xid(abcd0001)
dhcp_discover: making request
dhcp_discover: realloc()ing
dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)
dhcp_discover: deleting()ing
dhcp_discover: SELECTING
dhcp_discover(): set request timeout 2000 msecs
dhcp_fine_tmr(): request timeout
dhcp_timeout()
dhcp_timeout(): restarting discovery
dhcp_discover()
transaction id xid(abcd0001)
dhcp_discover: making request
dhcp_discover: realloc()ing
dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)
dhcp_discover: deleting()ing
dhcp_discover: SELECTING
dhcp_discover(): set request timeout 4000 msecs
dhcp_fine_tmr(): request timeout
dhcp_timeout()
dhcp_timeout(): restarting discovery
dhcp_discover()
transaction id xid(abcd0001)
dhcp_discover: making request
dhcp_discover: realloc()ing
dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)
dhcp_discover: deleting()ing
dhcp_discover: SELECTING
dhcp_discover(): set request timeout 8000 msecs
dhcp_fine_tmr(): request timeout
dhcp_timeout()
dhcp_timeout(): restarting discovery
dhcp_discover()
transaction id xid(abcd0001)
dhcp_discover: making request
dhcp_discover: realloc()ing
dhcp_discover: sendto(DISCOVER, IP_ADDR_BROADCAST, DHCP_SERVER_PORT)
dhcp_discover: deleting()ing
dhcp_discover: SELECTING
dhcp_discover(): set request timeout 16000 msecs

已确认这是路由器本身的问题，换个路由器就好了。

修改网卡的mac地址（如00:12:34:56:78:90）也能解决问题。