[Bug 1745540] [NEW] Ubuntu 17.10 - DNS query via TCP not working

[Dmitry Alexandrov]

Public bug reported:

TL:DR seem's like "ping/wget" etc become dislike truncated UDP DNS reply and the become tell "Temporary failure in name resolution" instead fallback to TCP protocol...
 


https://github.com/DNSCrypt/dnscrypt-proxy/issues/2

I'm using DNSCrypt-proxy running at 127.0.2.1:53

me at nb:~$ cat /etc/resolv.conf 
nameserver 127.0.2.1


me at nb:~$ nslookup ya.ru
Server:     127.0.2.1
Address:    127.0.2.1#53

Non-authoritative answer:
Name:   ya.ru
Address: 87.250.250.242

me at nb:~$ ping ya.ru
PING ya.ru (87.250.250.242) 56(84) bytes of data.
64 bytes from ya.ru (87.250.250.242): icmp_seq=1 ttl=50 time=31.3 ms
^C
--- ya.ru ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 31.320/31.320/31.320/0.000 ms

now I'm setting TCPOnly on into /etc/dnscrypt-proxy/dnscrypt-proxy.conf

me at nb:~$ sudo service dnscrypt-proxy restart
me at nb:~$ nslookup ya.ru
;; Truncated, retrying in TCP mode.
Server:     127.0.2.1
Address:    127.0.2.1#53

Non-authoritative answer:
Name:   ya.ru
Address: 87.250.250.242

me at nb:~$ ping ya.ru
ping: ya.ru: Temporary failure in name resolution

Is it possible to serve DNS over UDP but communicate between DNSCrypt
proxy and DNSCrypt server over TCP?

** Affects: resolvconf (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: dns

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https://bugs.launchpad.net/bugs/1745540

Title:
  Ubuntu 17.10 - DNS query via TCP not working

Status in resolvconf package in Ubuntu:
  New

Bug description:
  TL:DR seem's like "ping/wget" etc become dislike truncated UDP DNS reply and the become tell "Temporary failure in name resolution" instead fallback to TCP protocol...
   


  
  https://github.com/DNSCrypt/dnscrypt-proxy/issues/2

  I'm using DNSCrypt-proxy running at 127.0.2.1:53

  me at nb:~$ cat /etc/resolv.conf 
  nameserver 127.0.2.1

  
  me at nb:~$ nslookup ya.ru
  Server:     127.0.2.1
  Address:    127.0.2.1#53

  Non-authoritative answer:
  Name:   ya.ru
  Address: 87.250.250.242

  me at nb:~$ ping ya.ru
  PING ya.ru (87.250.250.242) 56(84) bytes of data.
  64 bytes from ya.ru (87.250.250.242): icmp_seq=1 ttl=50 time=31.3 ms
  ^C
  --- ya.ru ping statistics ---
  1 packets transmitted, 1 received, 0% packet loss, time 0ms
  rtt min/avg/max/mdev = 31.320/31.320/31.320/0.000 ms

  now I'm setting TCPOnly on into /etc/dnscrypt-proxy/dnscrypt-
  proxy.conf

  me at nb:~$ sudo service dnscrypt-proxy restart
  me at nb:~$ nslookup ya.ru
  ;; Truncated, retrying in TCP mode.
  Server:     127.0.2.1
  Address:    127.0.2.1#53

  Non-authoritative answer:
  Name:   ya.ru
  Address: 87.250.250.242

  me at nb:~$ ping ya.ru
  ping: ya.ru: Temporary failure in name resolution

  Is it possible to serve DNS over UDP but communicate between DNSCrypt
  proxy and DNSCrypt server over TCP?

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