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