Por que recebo um erro ao resolver o nome do host no Linux?

Question

No Ubuntu 12.04 (Virtual Box) estou tentando resolver um nome de host usando

nslookup myhost 172.16.0.100

e recebo a resposta

Server:     172.16.0.100
Address:    172.16.0.100#53

** server can't find esy-buildserver: SERVFAIL

em que o IP 100.16.0.100 é o endereço de um servidor DNS interno da empresa. Qualquer conexão com a Internet da caixa do Linux para o mundo externo apenas funciona como de costume (pode ping google.com , por exemplo).

Na máquina windows, onde a caixa virtual com o Ubuntu 12.04 está rodando, eu faço (na linha de comando)

nslookup myhost

e obtenho o endereço IP correto, incluindo o IP do servidor DNS, que é 172.16.0.100 !!

Por que o comando nslookup funciona no Windows, mas não no Linux?

Informações adicionais:

• ipconfig na máquina do Windows (somente em alemão - é possível alterar isso para o inglês?)

  Ethernet-Adapter LAN-Verbindung 2:
  
  Medienstatus. . . . . . . . . . . : Medium getrennt
  Verbindungsspezifisches DNS-Suffix:
  
  Ethernet-Adapter LAN-Verbindung:
  
  Verbindungsspezifisches DNS-Suffix: myhost.ch
  Verbindungslokale IPv6-Adresse  . : fe80::1b2:42a7:102e:3e9
  IPv4-Adresse  . . . . . . . . . . : 172.16.5.16
  Subnetzmaske  . . . . . . . . . . : 255.255.255.0
  Standardgateway . . . . . . . . . : 172.16.5.1
  
  Ethernet-Adapter VirtualBox Host-Only Network:
  
  Verbindungsspezifisches DNS-Suffix:
  Verbindungslokale IPv6-Adresse  . : fe80::c1a3:5518:996e:5f
  IPv4-Adresse  . . . . . . . . . . : 192.168.56.1
  Subnetzmaske  . . . . . . . . . . : 255.255.255.0
  Standardgateway . . . . . . . . . :
  
  Tunneladapter isatap.myhost.ch:
  
  Medienstatus. . . . . . . . . . . : Medium getrennt
  Verbindungsspezifisches DNS-Suffix: myhost.ch
  
  Tunneladapter 6TO4 Adapter:
  
  Medienstatus. . . . . . . . . . . : Medium getrennt
  Verbindungsspezifisches DNS-Suffix:
  
  Tunneladapter isatap.{555CF642-7F0F-458A-BF05-81F5684C23D1}:
  
  Medienstatus. . . . . . . . . . . : Medium getrennt
  Verbindungsspezifisches DNS-Suffix:
  
  Tunneladapter isatap.{CAC63733-325B-44F7-AC88-D6649B265470}:
  
  Medienstatus. . . . . . . . . . . : Medium getrennt
  Verbindungsspezifisches DNS-Suffix:
  

• route print -4

  ===========================================================================
  Schnittstellenliste
  15...00 ff 55 5c f6 42 ......TeamViewer VPN Adapter
  11...e8 39 35 4e 73 16 ......Intel(R) 82579LM Gigabit Network Connection
  19...08 00 27 00 04 f7 ......VirtualBox Host-Only Ethernet Adapter
  1...........................Software Loopback Interface 1
  12...00 00 00 00 00 00 00 e0 Microsoft-ISATAP-Adapter
  13...00 00 00 00 00 00 00 e0 Microsoft-6zu4-Adapter
  14...00 00 00 00 00 00 00 e0 Microsoft-ISATAP-Adapter #2
  16...00 00 00 00 00 00 00 e0 Microsoft-ISATAP-Adapter #3
  ===========================================================================
  
  IPv4-Routentabelle
  ===========================================================================
  Aktive Routen:
  Keine
  Ständige Routen:
  Keine
  

• ifconfig na caixa do Linux

  eth0      Link encap:Ethernet  HWaddr 08:00:27:68:66:59
          inet addr:172.16.5.170  Bcast:172.16.5.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe68:6659/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:27955 errors:0 dropped:0 overruns:0 frame:0
          TX packets:15874 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:15451204 (15.4 MB)  TX bytes:2747503 (2.7 MB)
  
  lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:575 errors:0 dropped:0 overruns:0 frame:0
          TX packets:575 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:52064 (52.0 KB)  TX bytes:52064 (52.0 KB)