por qué digfunciona bien, pero buscar en mi enrutador NetGear directamente no funciona (aunque primero también lo accede, porque es mi DNS, NetGear lo ha 8.8.8.8configurado como prim dns). Mi NetGear tiene IP 192.168.1.1en LAN. Aquí adjunto el escenario completo. Mi análisis de tramas muestra que, en mi opinión, ambas solicitudes llegan al enrutador NetGear 192.168.1.1en el puerto 53encima de UDP. No se diferencian en nada más, ¿o sí? por favor ayuda.
La única diferencia, aparte de los diferentes números de fotogramas y otras diferencias obvias, observable para mí es
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
presente en el marco OK y falta en el paquete fallido (fallido, me refiero a ninguna respuesta de 192.168.1.1)
dig cf16.eu
; <<>> DiG 9.9.2-P2 <<>> cf16.eu
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 24482
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;cf16.eu. IN A
;; ANSWER SECTION:
cf16.eu. 3600 IN A 89.75.41.50
;; Query time: 10 msec
;; SERVER: 127.0.1.1#53(127.0.1.1)
;; WHEN: Wed May 8 17:47:05 2013
;; MSG SIZE rcvd: 52
pero:
dig @192.168.1.1 cf16.eu
; <<>> DiG 9.9.2-P2 <<>> @192.168.1.1 cf16.eu
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached
Paquetes Wireshark: excavar cf16.eu [OK]
No. Time Source Destination Protocol Length Info
340 4.775113000 192.168.1.3 192.168.1.1 DNS 78 Standard query 0x5fa2 A cf16.eu
Frame 340: 78 bytes on wire (624 bits), 78 bytes captured (624 bits) on interface 0
Interface id: 0
WTAP_ENCAP: 1
Arrival Time: May 8, 2013 17:47:04.131360000 CEST
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1368028024.131360000 seconds
[Time delta from previous captured frame: 0.005265000 seconds]
[Time delta from previous displayed frame: 0.005265000 seconds]
[Time since reference or first frame: 4.775113000 seconds]
Frame Number: 340
Frame Length: 78 bytes (624 bits)
Capture Length: 78 bytes (624 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ip:udp:dns]
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
Ethernet II, Src: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc), Dst: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
Destination: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
Address: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Source: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc)
Address: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IP (0x0800)
Internet Protocol Version 4, Src: 192.168.1.3 (192.168.1.3), Dst: 192.168.1.1 (192.168.1.1)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))
0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Capable Transport) (0x00)
Total Length: 64
Identification: 0xf650 (63056)
Flags: 0x00
0... .... = Reserved bit: Not set
.0.. .... = Don't fragment: Not set
..0. .... = More fragments: Not set
Fragment offset: 0
Time to live: 64
Protocol: UDP (17)
Header checksum: 0x0108 [correct]
[Good: True]
[Bad: False]
Source: 192.168.1.3 (192.168.1.3)
Destination: 192.168.1.1 (192.168.1.1)
[Source GeoIP: Unknown]
[Destination GeoIP: Unknown]
User Datagram Protocol, Src Port: 47841 (47841), Dst Port: domain (53)
Source port: 47841 (47841)
Destination port: domain (53)
Length: 44
Checksum: 0x4831 [validation disabled]
[Good Checksum: False]
[Bad Checksum: False]
Domain Name System (query)
Transaction ID: 0x5fa2
Flags: 0x0120 Standard query
0... .... .... .... = Response: Message is a query
.000 0... .... .... = Opcode: Standard query (0)
.... ..0. .... .... = Truncated: Message is not truncated
.... ...1 .... .... = Recursion desired: Do query recursively
.... .... .0.. .... = Z: reserved (0)
.... .... ..1. .... = AD bit: Set
[Expert Info (Warn/Security): AD bit set in DNS Query]
[Message: AD bit set in DNS Query]
[Severity level: Warn]
[Group: Security]
.... .... ...0 .... = Non-authenticated data: Unacceptable
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
cf16.eu: type A, class IN
Name: cf16.eu
Type: A (Host address)
Class: IN (0x0001)
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
cavar 192.168.1.1 cf16.eu [falla]
No. Time Source Destination Protocol Length Info
603 7.972662000 192.168.1.3 192.168.1.1 DNS 78 Standard query 0xc755 A cf16.eu
Frame 603: 78 bytes on wire (624 bits), 78 bytes captured (624 bits) on interface 0
Interface id: 0
WTAP_ENCAP: 1
Arrival Time: May 8, 2013 17:49:36.816366000 CEST
[Time shift for this packet: 0.000000000 seconds]
Epoch Time: 1368028176.816366000 seconds
[Time delta from previous captured frame: 0.402535000 seconds]
[Time delta from previous displayed frame: 0.402535000 seconds]
[Time since reference or first frame: 7.972662000 seconds]
Frame Number: 603
Frame Length: 78 bytes (624 bits)
Capture Length: 78 bytes (624 bits)
[Frame is marked: False]
[Frame is ignored: False]
[Protocols in frame: eth:ip:udp:dns]
Ethernet II, Src: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc), Dst: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
Destination: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
Address: Netgear_bb:b7:2c (00:1b:2f:bb:b7:2c)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Source: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc)
Address: Micro-St_4b:47:dc (d4:3d:7e:4b:47:dc)
.... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
.... ...0 .... .... .... .... = IG bit: Individual address (unicast)
Type: IP (0x0800)
Internet Protocol Version 4, Src: 192.168.1.3 (192.168.1.3), Dst: 192.168.1.1 (192.168.1.1)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00: Not-ECT (Not ECN-Capable Transport))
0000 00.. = Differentiated Services Codepoint: Default (0x00)
.... ..00 = Explicit Congestion Notification: Not-ECT (Not ECN-Capable Transport) (0x00)
Total Length: 64
Identification: 0xf651 (63057)
Flags: 0x00
0... .... = Reserved bit: Not set
.0.. .... = Don't fragment: Not set
..0. .... = More fragments: Not set
Fragment offset: 0
Time to live: 64
Protocol: UDP (17)
Header checksum: 0x0107 [correct]
[Good: True]
[Bad: False]
Source: 192.168.1.3 (192.168.1.3)
Destination: 192.168.1.1 (192.168.1.1)
[Source GeoIP: Unknown]
[Destination GeoIP: Unknown]
User Datagram Protocol, Src Port: 37226 (37226), Dst Port: domain (53)
Source port: 37226 (37226)
Destination port: domain (53)
Length: 44
Checksum: 0x09f5 [validation disabled]
[Good Checksum: False]
[Bad Checksum: False]
Domain Name System (query)
Transaction ID: 0xc755
Flags: 0x0120 Standard query
0... .... .... .... = Response: Message is a query
.000 0... .... .... = Opcode: Standard query (0)
.... ..0. .... .... = Truncated: Message is not truncated
.... ...1 .... .... = Recursion desired: Do query recursively
.... .... .0.. .... = Z: reserved (0)
.... .... ..1. .... = AD bit: Set
[Expert Info (Warn/Security): AD bit set in DNS Query]
[Message: AD bit set in DNS Query]
[Severity level: Warn]
[Group: Security]
.... .... ...0 .... = Non-authenticated data: Unacceptable
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
cf16.eu: type A, class IN
Name: cf16.eu
Type: A (Host address)
Class: IN (0x0001)
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
Respuesta1
En este escenario, su enrutador actúa como un servidor DNS para solicitudes locales y actúa como un reenviador para direcciones desconocidas, realizando la consulta en el servidor 8.8.8.8, procesando la respuesta y luego enviando un paquete indicando el resultado. si usa excavar sin una referencia de servidor, usa la zona raíz para resolver y su enrutador reenviará la búsqueda a los servidores raíz para su resolución.
Cuando especifica un servidor en excavación, normalmente intenta determinar si la zona que acaba de crear/importar funciona bien en este servidor, por lo que no se puede permitir que se produzca el reenvío o se ocultaría una falla potencial en el servidor en el que está específicamente. intentando probar. no estás diciendo "dame información sobre este dominio", sino "dame la información que este servidor específico tiene sobre este dominio".
Dado que el dominio en cuestión no reside en una zona que realmente exista en el enrutador, no obtiene respuesta.
Ver más información aquí: http://en.wikipedia.org/wiki/Dig_%28command%29
Cuando no se especifica un servidor de nombres específico en la invocación del comando, utilizará el solucionador predeterminado del sistema operativo, generalmente configurado a través del archivo resolv.conf. Sin ningún argumento, consulta la zona raíz del DNS.