One of the SSL VPN network extension difference between under win7 and xp.

Publication Date:  2012-09-24 Views:  343 Downloads:  0
Issue Description
When we use the network extension and use local PC to access company internal network from far end ,the dialling is normal, we find the win7 cannot open Web after dialling but xp can.Why ?
Alarm Information
None.
Handling Process
For approving the suppose above to have a test as follows:
1、 It cannot resolve domain name after taking out the far end physical network card of XP
2、 It cannot resolve domain name after taking out the far end physical network card of WIN7
3、 Both WIN7 and XP can resolve domain name normally after adding DNS conguration
The state of virtual network interface card without network extension configuring WIN7 and XP connec SSL VPN under DNS,as follows:
xp
Physical Address. . . . . . . . . : x-x-x-x-64-B7
Dhcp Enabled. . . . . . . . . . . : no
IP Address. . . . . . . . . . . . : 10.x.x.172
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . :
win 7
Physical Address. . . . . . . . . : x-x-x-x-64-B1
Dhcp Enabled. . . . . . . . . . . : no
IP Address. . . . . . . . . . . . : 10.x.x.170
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . : 0.0.0.0
 
Root Cause
This is the problem of dns analytic,win7 cannot get the right DNS.why can xp get the right DNS? We can find the equipment doesn’t be configured option after assigning IP and getting DNS,but why can XP access the network? Does the way to deal with the network extension have some difference between XP and WIN7 
Suggestions
The analysis which is  Based on the windows operating system application layer working arrangment as follows:
The WIN7 client will take the DNS information after dialling,when we use DNS to resolve domain name ,WIN7 will use virtual network interface card to resolve DNS address itself ,if SVN has no the configuration DNS information ,the virtual network interface card of WIN7 will take DNS address of 0.0.0.0 automatically.The dialling can be successful at this time ,but it cannot resolve domain name.
When virtual network interface card of XP doesn’t configure DNS address information, it won’t take DNS information,so it will match the physical network card of DNS at first when it resolves domain name, if the far end PC physical has DNS ,it can resolve domain name normally after dialling.

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