Question and response
Question
dig smtp.21vianet.com. TXT
Answer
smtp.21vianet.com. 600 TXT "v=spf1 ip4:59.151.19.91 ip4:106.120.80.109 -all"
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0