本文出自Simmy的个人blog：西米在线
http://simmyonline.com/archives/72.html
It's common to know that DNS use both protocal UDP and TCP for data transmission,but why and how ?
here's the note
DNS uses TCP instead of UDP for transmitting data when the data size
exceeds 512 bytes. DNS also uses TCP for transferring entire DNS zones
between zones. In either case, port 53 is used.
exceeds 512 bytes. DNS also uses TCP for transferring entire DNS zones
between zones. In either case, port 53 is used.
本文转simmy51CTO博客，原文链接：http://blog.51cto.com/helpdesk/122661
，如需转载请自行联系原作者
