问答题

某时刻，一台PC开始抓取数据报文，其中一个报文展开如下所示。
IP:-----IP Header-----
IP:
IP:Version=4, header length=20 bytes
IP:Type of service=00
IP: 000......=routine
IP: ...0......=normal delay
IP: ....0.....=normal throughput
IP: .....0....=normal reliability
IP: ......0...=ECT bit-transport protocol
IP: .......0..=CE bit-no congestion
IP:Total length =166 bytes
IP:IdentifiCation =32897
IP:Flags =0X
IP: .0........=may fragment
IP: ..0.......=last fragment
IP:Fragment offset=0 bytes
IP:Time to live =64 Second/hops
IP:Protocol =17
IP:Header checksum=7A58(COrrect)
IP:Source addresS =[172.16.19.1]
IP:DeStination address=[172.16.20.76]
IP:No options
IP:
试回答以下问题： 该IP报文的源地址和目的地址是什么