Same results using the vagrant vm configured bind server:

vagrant@ubuntu-bionic:~$ nslookup ubuntu.com - 192.168.0.130
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   ubuntu.com
Address: 91.189.94.40
** server can't find ubuntu.com: SERVFAIL

vagrant@ubuntu-bionic:~$ nslookup amazon.com - 192.168.0.130
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   amazon.com
Address: 176.32.103.205
Name:   amazon.com
Address: 205.251.242.103
Name:   amazon.com
Address: 176.32.98.166
** server can't find amazon.com: SERVFAIL

vagrant@ubuntu-bionic:~$ nslookup google.com - 192.168.0.130
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   google.com
Address: 172.217.3.14
Name:   google.com
Address: 2607:f8b0:400f:801::200e

vagrant@ubuntu-bionic:~$


Pauses are the same upon the first nslookup for the domain.  After the first 
lookup, the entry is cached and there isn't a pause between the ipv4 and ipv6 
entries.

You can see the pause in the strace output (attached):
vagrant@ubuntu-bionic:~$ strace -ftt nslookup cononical.com - 192.168.0.130 2> 
strace.out


[pid  1836] 18:39:56.769691 futex(0x7f5ae18c30c8, FUTEX_WAIT_PRIVATE, 0, NULL 
<unfinished ...>
[pid  1838] 18:39:57.576985 <... epoll_wait resumed> [{EPOLLIN, {u32=20, 
u64=20}}], 64, -1) = 1


Also doing some playing with nslookup and IPV6 settings:

vagrant@ubuntu-bionic:~$ nslookup
> server 192.168.0.130
Default server: 192.168.0.130
Address: 192.168.0.130#53
> ubuntu.com
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   ubuntu.com
Address: 91.189.94.40
** server can't find ubuntu.com: SERVFAIL
> set querytype=a
> ubuntu.com
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   ubuntu.com
Address: 91.189.94.40
> set querytype=aaaa
> ubuntu.com
Server:         192.168.0.130
Address:        192.168.0.130#53

** server can't find ubuntu.com: SERVFAIL
> google.com
Server:         192.168.0.130
Address:        192.168.0.130#53

Non-authoritative answer:
Name:   google.com
Address: 2607:f8b0:400f:800::200e

So definitely something going on with the IPV6.  In your configuration,
do you get IPV6 records for google.com?

** Attachment added: "strace.out"
   
https://bugs.launchpad.net/ubuntu/+source/bind9/+bug/1787739/+attachment/5202670/+files/strace.out

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1787739

Title:
  postfix name lookup failed after dist-upgrade (Aug-2018)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/bind9/+bug/1787739/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to