Windows 7 laptop with two active network connections will not perform DNS AAAA lookup under certain conditions
- by Jeff Loughridge
My laptop has two network interfaces. The Ethernet interface connects directly to my provider's edge router. It obtains an IPv6 address via SLAAC. I manually set an IPv6 DNS server. The wireless interface connects to a CPE router that doesn't understand IPv6.
If the wireless interface is disabled, I can reach the IPv6 Internet with no problems using the Ethernet interface.
I run into problems when both interfaces are enabled and the wireless interface get its IPv4 DNS server via DHCP. Let's look at two scenarios.
Wireless interface obtains IPv4 DNS server via DHCP - The CPE router (192.168.0.1) sends its address as the DNS server. In this scenario, Windows 7 will not perform AAAA lookups. The browser uses IPv4 transit to reach dual stack web sites. I can't reach IPv6-only web sites using domain names. I can reach IPv6-enabled web sites using IPv6 literals instead of the domain name.
Wireless interface is manually configured with OpenDNS DNS server - Windows 7 performs AAAA lookups using IPv6 transit (via the Ethernet). Everything works fine.
My dual homed set-up is definitely not standard. Still, the behavior is very strange to me. A valid IPv6 interface exists in my Ethernet interface. Why won't Windows attempt AAAA lookups in scenario #1?
I've included the output of ipconfig /all and netstat -rn.
C:\Program Files\Console>ipconfig /all
Windows IP Configuration
Host Name . . . . . . . . . . . . : jake
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : res.openband.net
Wireless LAN adapter Wireless Network Connection 2:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft Virtual WiFi Miniport Adapter
Physical Address. . . . . . . . . : C0-CB-38-06-54-F9
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Wireless LAN adapter Wireless Network Connection:
Connection-specific DNS Suffix . : res.openband.net
Description . . . . . . . . . . . : DW1520 Wireless-N WLAN Half-Mini Card
Physical Address. . . . . . . . . : C0-CB-38-06-54-F9
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::fc39:9293:7d01:4a75%13(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.105(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Wednesday, July 11, 2012 7:35:21 AM
Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 9:49:46 AM
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DHCPv6 IAID . . . . . . . . . . . : 364956472
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C
DNS Servers . . . . . . . . . . . : 208.67.222.222
NetBIOS over Tcpip. . . . . . . . : Enabled
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : res.openband.net
Description . . . . . . . . . . . : Intel(R) 82577LM Gigabit Network Connection
Physical Address. . . . . . . . . : 5C-26-0A-03-23-5C
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IPv6 Address. . . . . . . . . . . : 2607:2600:1:850:c0e9:211a:fd05:4e0b(Preferred)
Temporary IPv6 Address. . . . . . : 2607:2600:1:850:3d29:1839:62db:c4c1(Preferred)
Link-local IPv6 Address . . . . . : fe80::c0e9:211a:fd05:4e0b%12(Preferred)
IPv4 Address. . . . . . . . . . . : 10.52.2.51(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Lease Obtained. . . . . . . . . . : Monday, July 09, 2012 8:55:07 AM
Lease Expires . . . . . . . . . . : Thursday, July 12, 2012 7:30:05 AM
Default Gateway . . . . . . . . . : fe80::214:6aff:fe51:7f3f%12
10.52.2.1
DHCP Server . . . . . . . . . . . : 216.40.77.244
DNS Servers . . . . . . . . . . . : 2620:0:ccc::2
2620:0:ccd::2
216.40.77.126
216.40.77.244
NetBIOS over Tcpip. . . . . . . . : Enabled
Ethernet adapter VMware Network Adapter VMnet1:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet1
Physical Address. . . . . . . . . : 00-50-56-C0-00-01
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::4c61:495b:229e:281e%14(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.40.1(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 469782614
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C
DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled
Ethernet adapter VMware Network Adapter VMnet8:
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet8
Physical Address. . . . . . . . . : 00-50-56-C0-00-08
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f996:61eb:8c00:45e6%15(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.17.1(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 486559830
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-80-F8-14-5C-26-0A-03-23-5C
DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
fec0:0:0:ffff::2%1
fec0:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Enabled
C:\Program Files\Console>netstat -rn
===========================================================================
Interface List
17...c0 cb 38 06 54 f9 ......Microsoft Virtual WiFi Miniport Adapter
13...c0 cb 38 06 54 f9 ......DW1520 Wireless-N WLAN Half-Mini Card
12...5c 26 0a 03 23 5c ......Intel(R) 82577LM Gigabit Network Connection
11...5c ac 4c f8 b8 55 ......Bluetooth Device (Personal Area Network)
14...00 50 56 c0 00 01 ......VMware Virtual Ethernet Adapter for VMnet1
15...00 50 56 c0 00 08 ......VMware Virtual Ethernet Adapter for VMnet8
1...........................Software Loopback Interface 1
===========================================================================
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 10.52.2.1 10.52.2.51 10
0.0.0.0 0.0.0.0 192.168.0.1 192.168.0.105 100
10.52.2.0 255.255.254.0 On-link 10.52.2.51 261
10.52.2.51 255.255.255.255 On-link 10.52.2.51 261
10.52.3.255 255.255.255.255 On-link 10.52.2.51 261
127.0.0.0 255.0.0.0 On-link 127.0.0.1 306
127.0.0.1 255.255.255.255 On-link 127.0.0.1 306
127.255.255.255 255.255.255.255 On-link 127.0.0.1 306
192.168.0.0 255.255.255.0 On-link 192.168.0.105 306
192.168.0.105 255.255.255.255 On-link 192.168.0.105 306
192.168.0.255 255.255.255.255 On-link 192.168.0.105 306
192.168.17.0 255.255.255.0 On-link 192.168.17.1 276
192.168.17.1 255.255.255.255 On-link 192.168.17.1 276
192.168.17.255 255.255.255.255 On-link 192.168.17.1 276
192.168.40.0 255.255.255.0 On-link 192.168.40.1 276
192.168.40.1 255.255.255.255 On-link 192.168.40.1 276
192.168.40.255 255.255.255.255 On-link 192.168.40.1 276
224.0.0.0 240.0.0.0 On-link 127.0.0.1 306
224.0.0.0 240.0.0.0 On-link 10.52.2.51 261
224.0.0.0 240.0.0.0 On-link 192.168.0.105 306
224.0.0.0 240.0.0.0 On-link 192.168.40.1 276
224.0.0.0 240.0.0.0 On-link 192.168.17.1 276
255.255.255.255 255.255.255.255 On-link 127.0.0.1 306
255.255.255.255 255.255.255.255 On-link 10.52.2.51 261
255.255.255.255 255.255.255.255 On-link 192.168.0.105 306
255.255.255.255 255.255.255.255 On-link 192.168.40.1 276
255.255.255.255 255.255.255.255 On-link 192.168.17.1 276
===========================================================================
Persistent Routes:
None
IPv6 Route Table
===========================================================================
Active Routes:
If Metric Network Destination Gateway
12 261 ::/0 fe80::214:6aff:fe51:7f3f
1 306 ::1/128 On-link
12 13 2607:2600:1:850::/64 On-link
12 261 2607:2600:1:850:3d29:1839:62db:c4c1/128
On-link
12 261 2607:2600:1:850:c0e9:211a:fd05:4e0b/128
On-link
12 261 fe80::/64 On-link
13 281 fe80::/64 On-link
14 276 fe80::/64 On-link
15 276 fe80::/64 On-link
14 276 fe80::4c61:495b:229e:281e/128
On-link
12 261 fe80::c0e9:211a:fd05:4e0b/128
On-link
15 276 fe80::f996:61eb:8c00:45e6/128
On-link
13 281 fe80::fc39:9293:7d01:4a75/128
On-link
1 306 ff00::/8 On-link
12 261 ff00::/8 On-link
13 281 ff00::/8 On-link
14 276 ff00::/8 On-link
15 276 ff00::/8 On-link
===========================================================================
Persistent Routes:
None