我有几个bind服务器最近升级到了 Ubuntu 16.04（从 14.04 开始）。Crondig . ns每天运行一次以获取bind配置中使用的根服务器的更新列表。
cron 运行的脚本检查ADDTIONAL SECTION输出以确定查询是否失败。自升级以来，它一直失败，因为部分不再被返回。有人知道这是怎么回事吗？我还没有在谷歌上找到任何具体的东西。
在 14.04 dig 返回此
# dig . ns
; <<>> DiG 9.9.5-3ubuntu0.19-Ubuntu <<>> . ns
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1492
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 27
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 900
;; QUESTION SECTION:
;. IN NS
;; ANSWER SECTION:
. 73048 IN NS e.root-servers.net.
. 73048 IN NS b.root-servers.net.
. 73048 IN NS j.root-servers.net.
. 73048 IN NS d.root-servers.net.
. 73048 IN NS m.root-servers.net.
. 73048 IN NS k.root-servers.net.
. 73048 IN NS g.root-servers.net.
. 73048 IN NS l.root-servers.net.
. 73048 IN NS c.root-servers.net.
. 73048 IN NS i.root-servers.net.
. 73048 IN NS h.root-servers.net.
. 73048 IN NS a.root-servers.net.
. 73048 IN NS f.root-servers.net.
;; ADDITIONAL SECTION:
a.root-servers.net. 222215 IN A 198.41.0.4
a.root-servers.net. 308618 IN AAAA 2001:503:ba3e::2:30
b.root-servers.net. 73048 IN A 199.9.14.201
b.root-servers.net. 73048 IN AAAA 2001:500:200::b
c.root-servers.net. 308618 IN A 192.33.4.12
c.root-servers.net. 308618 IN AAAA 2001:500:2::c
d.root-servers.net. 73048 IN A 199.7.91.13
d.root-servers.net. 73048 IN AAAA 2001:500:2d::d
e.root-servers.net. 73048 IN A 192.203.230.10
e.root-servers.net. 73048 IN AAAA 2001:500:a8::e
f.root-servers.net. 73048 IN A 192.5.5.241
f.root-servers.net. 75235 IN AAAA 2001:500:2f::f
g.root-servers.net. 308618 IN A 192.112.36.4
g.root-servers.net. 75235 IN AAAA 2001:500:12::d0d
h.root-servers.net. 308618 IN A 198.97.190.53
h.root-servers.net. 312215 IN AAAA 2001:500:1::53
i.root-servers.net. 73048 IN A 192.36.148.17
i.root-servers.net. 75235 IN AAAA 2001:7fe::53
j.root-servers.net. 73048 IN A 192.58.128.30
j.root-servers.net. 75235 IN AAAA 2001:503:c27::2:30
k.root-servers.net. 73048 IN A 193.0.14.129
k.root-servers.net. 75235 IN AAAA 2001:7fd::1
l.root-servers.net. 73048 IN A 199.7.83.42
l.root-servers.net. 75235 IN AAAA 2001:500:9f::42
m.root-servers.net. 73048 IN A 202.12.27.33
m.root-servers.net. 75235 IN AAAA 2001:dc3::35
;; Query time: 1 msec
;; SERVER: 192.168.136.183#53(192.168.136.183)
;; WHEN: Thu Feb 28 09:31:26 CST 2019
;; MSG SIZE rcvd: 811
在 16.04 上 dig 返回此
# dig . ns
; <<>> DiG 9.10.3-P4-Ubuntu <<>> . ns
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57497
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;. IN NS
;; ANSWER SECTION:
. 55229 IN NS j.root-servers.net.
. 55229 IN NS a.root-servers.net.
. 55229 IN NS h.root-servers.net.
. 55229 IN NS b.root-servers.net.
. 55229 IN NS d.root-servers.net.
. 55229 IN NS i.root-servers.net.
. 55229 IN NS c.root-servers.net.
. 55229 IN NS m.root-servers.net.
. 55229 IN NS g.root-servers.net.
. 55229 IN NS l.root-servers.net.
. 55229 IN NS f.root-servers.net.
. 55229 IN NS e.root-servers.net.
. 55229 IN NS k.root-servers.net.
;; Query time: 1 msec
;; SERVER: 192.168.32.4#53(192.168.32.4)
;; WHEN: Thu Feb 28 09:30:41 CST 2019
;; MSG SIZE rcvd: 239
更新：16.04，具有+additional
# dig . ns +additional
; <<>> DiG 9.10.3-P4-Ubuntu <<>> . ns +additional
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32682
;; flags: qr rd ra; QUERY: 1, ANSWER: 13, AUTHORITY: 0, ADDITIONAL: 2
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;. IN NS
;; ANSWER SECTION:
. 402756 IN NS l.root-servers.net.
. 402756 IN NS h.root-servers.net.
. 402756 IN NS j.root-servers.net.
. 402756 IN NS b.root-servers.net.
. 402756 IN NS e.root-servers.net.
. 402756 IN NS g.root-servers.net.
. 402756 IN NS m.root-servers.net.
. 402756 IN NS f.root-servers.net.
. 402756 IN NS d.root-servers.net.
. 402756 IN NS a.root-servers.net.
. 402756 IN NS c.root-servers.net.
. 402756 IN NS k.root-servers.net.
. 402756 IN NS i.root-servers.net.
;; ADDITIONAL SECTION:
a.root-servers.net. 107396 IN A 198.41.0.4
;; Query time: 0 msec
;; SERVER: 192.168.32.4#53(192.168.32.4)
;; WHEN: Wed Mar 06 09:57:10 CST 2019
;; MSG SIZE rcvd: 255