一般来说,大多数人会认为compute-1.amazonaws.com
是compute-1
amazonaws.com
但显然事实并非如此。根据公共后缀列表,compute-1.amazonaws.com
就像com
或一样,是一个后缀net
。
为什么会这样?这有什么意义?它是完全任意的,仅取决于它是否包含在公共后缀列表中,还是有更多内容?
答案1
该子域名仅作为 SOA 入口而存在。
root:~# dig compute-1.amazonaws.com
; <<>> DiG 9.8.4-rpz2+rl005.12-P1 <<>> @dns-external-master.amazon.com compute-1.amazonaws.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32744
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;compute-1.amazonaws.com. IN A
;; AUTHORITY SECTION:
compute-1.amazonaws.com. 5 IN SOA dns-external-master.amazon.com. hostmaster.amazon.com. 2013092946 180 60 2592000 5
;; Query time: 4 msec
;; SERVER: 204.74.108.1#53(204.74.108.1)
;; WHEN: Thu Jun 4 11:37:42 2015
;; MSG SIZE rcvd: 115