warum digfunktioniert es OK, aber mein NetGear-Router direkt funktioniert nicht (obwohl der erste auch dorthin geht, weil es mein DNS ist, NetGear selbst hat es 8.8.8.8als primären DNS eingestellt). Mein NetGear hat eine IP 192.168.1.1im LAN. Hier habe ich das komplette Szenario angehängt. Meine Analyse der Frames zeigt meiner Meinung nach, dass beide Anfragen 192.168.1.1über den Port 53auf UDP an den Router NetGear kommen. Sonst unterscheiden sie sich nicht, oder doch? Bitte helfen Sie.
Der einzige Unterschied, der mir neben den unterschiedlichen Framenummern und anderen offensichtlichen Unterschieden auffällt, ist
[Coloring Rule Name: UDP]
[Coloring Rule String: udp]
im OK-Frame vorhanden, fehlt jedoch im fehlgeschlagenen Paket (fehlgeschlagen – ich meine, überhaupt keine Antwort von 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
Aber:
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
Wireshark-Pakete: dig 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
dig 192.168.1.1 cf16.eu [Fehler]
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
Antwort1
In diesem Szenario fungiert Ihr Router als DNS-Server für lokale Anfragen und als Weiterleiter für unbekannte Adressen, indem er die Abfrage an den 8.8.8.8-Server stellt, die Antwort verarbeitet und anschließend ein Paket mit dem Ergebnis zurücksendet. Wenn Sie „dig“ ohne Serverreferenz verwenden, wird zur Auflösung die Root-Zone verwendet und Ihr Router leitet die Suche zur Auflösung an die Root-Server weiter.
Wenn Sie in Dig einen Server angeben, versuchen Sie normalerweise zu ermitteln, ob die Zone, die Sie gerade erstellt/importiert haben, auf diesem Server einwandfrei funktioniert. Eine Weiterleitung darf daher nicht zugelassen werden, da dadurch ein potenzieller Fehler auf dem Server, den Sie speziell testen möchten, verborgen würde. Sie sagen nicht „Geben Sie mir Informationen zu dieser Domäne“, sondern „Geben Sie mir die Informationen, die dieser spezielle Server zu dieser Domäne hat“.
Da sich die betreffende Domäne nicht in einer tatsächlich auf dem Router vorhandenen Zone befindet, erhalten Sie keine Antwort.
Weitere Informationen finden Sie hier: http://en.wikipedia.org/wiki/Dig_%28command%29
Wenn beim Befehlsaufruf kein bestimmter Nameserver angegeben wird, wird der Standard-Resolver des Betriebssystems verwendet, der normalerweise über die Datei resolv.conf konfiguriert wird. Ohne Argumente wird die DNS-Stammzone abgefragt.