VPN Connection causes DNS to use wrong DNS server
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Bryan
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Published on 2012-02-02T10:31:31Z
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2012/06/21
15:18 UTC
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I have a Windows 7 PC on our company network (which is a member of our Active Directory). Everything works fine until I open a VPN connection to a customer's site.
When I do connect, I lose network access to shares on the network, including directories such as 'Application Data' that we have a folder redirection policy for. As you can imagine, this makes working on the PC very difficult, as desktop shortcuts stop working, software stops working properly due to having 'Application Data' pulled from under it.
Our network is routed (10.58.5.0/24), with other local subnets existing within the scope of 10.58.0.0/16. The remote network is on 192.168.0.0/24.
I've tracked the issue down to being DNS related. As soon as I open the VPN tunnel, all my DNS traffic goes via the remote network, which explains the loss of local resources, but my question is, how can I force local DNS queries to go to our local DNS servers rather than our customers?
The output of ipconfig /all when not connected to the VPN is below:
Windows IP Configuration
Host Name . . . . . . . . . . . . : 7k5xy4j
Primary Dns Suffix . . . . . . . : mydomain.local
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : mydomain.local
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : mydomain.local
Description . . . . . . . . . . . : Broadcom NetLink (TM) Gigabit Ethernet
Physical Address. . . . . . . . . : F0-4D-A2-DB-3B-CA
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::9457:c5e0:6f10:b298%10(Preferred)
IPv4 Address. . . . . . . . . . . : 10.58.5.89(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 31 January 2012 15:55:47
Lease Expires . . . . . . . . . . : 10 February 2012 10:11:30
Default Gateway . . . . . . . . . : 10.58.5.1
DHCP Server . . . . . . . . . . . : 10.58.3.32
DHCPv6 IAID . . . . . . . . . . . : 250629538
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-AC-76-2D-F0-4D-A2-DB-3B-CA
DNS Servers . . . . . . . . . . . : 10.58.3.32
10.58.3.33
NetBIOS over Tcpip. . . . . . . . : Enabled
This is the output of the same command with the VPN tunnel connected:
Windows IP Configuration
Host Name . . . . . . . . . . . . : 7k5xy4j
Primary Dns Suffix . . . . . . . : mydomain.local
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : mydomain.local
PPP adapter Customer Domain:
Connection-specific DNS Suffix . : customerdomain.com
Description . . . . . . . . . . . : CustomerDomain
Physical Address. . . . . . . . . :
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
IPv4 Address. . . . . . . . . . . : 192.168.0.85(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.255
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . : 192.168.0.16
192.168.0.17
Primary WINS Server . . . . . . . : 192.168.0.17
NetBIOS over Tcpip. . . . . . . . : Disabled
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : mydomain.local
Description . . . . . . . . . . . : Broadcom NetLink (TM) Gigabit Ethernet
Physical Address. . . . . . . . . : F0-4D-A2-DB-3B-CA
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::9457:c5e0:6f10:b298%10(Preferred)
IPv4 Address. . . . . . . . . . . : 10.58.5.89(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 31 January 2012 15:55:47
Lease Expires . . . . . . . . . . : 10 February 2012 10:11:30
Default Gateway . . . . . . . . . : 10.58.5.1
DHCP Server . . . . . . . . . . . : 10.58.3.32
DHCPv6 IAID . . . . . . . . . . . : 250629538
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-AC-76-2D-F0-4D-A2-DB-3B-CA
DNS Servers . . . . . . . . . . . : 10.58.3.32
10.58.3.33
NetBIOS over Tcpip. . . . . . . . : Enabled
Routing table
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 10.58.5.1 10.58.5.89 20
10.58.5.0 255.255.255.0 On-link 10.58.5.89 276
10.58.5.89 255.255.255.255 On-link 10.58.5.89 276
10.58.5.255 255.255.255.255 On-link 10.58.5.89 276
91.194.153.42 255.255.255.255 10.58.5.1 10.58.5.89 21
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
192.168.0.0 255.255.255.0 192.168.0.95 192.168.0.85 21
192.168.0.85 255.255.255.255 On-link 192.168.0.85 276
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 10.58.5.89 276
224.0.0.0 240.0.0.0 On-link 192.168.0.85 276
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 10.58.5.89 276
255.255.255.255 255.255.255.255 On-link 192.168.0.85 276
The binding order for the interfaces is as follows:
I've not configured the VPN tunnel to use the default gateway at the remote end, and network comms to nodes on both networks are fine. (i.e. I can ping any node on our network or the remote network).
I've modified the PPTP connection properties to use the DNS servers 10.58.3.32 followed by 192.168.0.16, yet the query still goes to 192.168.0.16.
Edit:
The local resources that disappear are hosted on domain DFS roots, which might (or might not) be relevant.
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