Hi

Having a problem with DHCP and DNS when using a VPN on Windows 8.1

All of a sudden last week we stopped getting DNS server IP's from the DHCP server on the VPN PPP service.  We get and IP but no DNS settings.

 As you can see below the PPP adapter dose not even list the option for a DNS server this is using a WiFi Hotspot off my phone

PPP adapter XXX VPN:

   Connection-specific DNS Suffix  . : XXX.int
   Description . . . . . . . . . . . : XXX VPN
   Physical Address. . . . . . . . . :
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 10.254.1.33(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.255
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Enabled
   Connection-specific DNS Suffix Search List :
                                        XXX.int
Wireless LAN adapter Wi-Fi:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Marvell AVASTAR Wireless-AC Network Controller
   Physical Address. . . . . . . . . : 4C-0B-BE-02-4C-E2
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::b81e:9d4:5f8d:9149%3(Preferred)
   IPv4 Address. . . . . . . . . . . : 172.20.10.3(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.240
   Lease Obtained. . . . . . . . . . : Thursday, 26 February 2015 1:54:59 PM
   Lease Expires . . . . . . . . . . : Friday, 27 February 2015 1:40:35 PM
   Default Gateway . . . . . . . . . : 172.20.10.1
   DHCP Server . . . . . . . . . . . : 172.20.10.1
   DHCPv6 IAID . . . . . . . . . . . : 55315390
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1C-45-F4-06-00-50-B6-77-78-54
   DNS Servers . . . . . . . . . . . : 172.20.10.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

I can only get the DNS working if I manually run the command

netsh interface ipv4 add dnsserver "xxx VPN" address=172.xx.xx.30

I've checked the DHCP server settings and and if I use a webpage on the sonicwall it uses a Aventail Smart Tunnel and I get a DNS server fine from the same DHCP server.  Just the windows VPN dose not work correctly.

If anyone has any ideas?

• Edited by chocky005 Thursday, February 26, 2015 3:56 AM

Hi Chocky,

As I know, when you are connecting to a VPN, client require IP information from VPN server instead of DHCP server.

When the RRAS server uses this type of proactive caching of DHCP address leases for remote access clients, it only records the following information for each lease response it obtains from the DHCP server:

The IP address of the DHCP server.

The client leased IP address (for later distribution to the Routing and Remote Access client).

The time at which the lease was obtained.

The time at which the lease expires.

The duration of the lease.

For more information about RRAS and DHCP

https://technet.microsoft.com/en-us/library/dd458962%28v=ws.10%29.aspx?f=255&MSPPError=-2147217396

So we suggest your check this issue with your VPN provider or run command you mentioned as a workaround.

Regards

D. Wu

• Proposed as answer by Alex ZhaozxMicrosoft contingent staff, Moderator Thursday, March 05, 2015 2:19 AM

Hi chocky,

As I mentioned, when you are connecting to a VPN, client require IP information from VPN server instead of DHCP server. And VPN server should pass their own DNS settings to VPN client if they have DNS settings by default. However, to prevent internal DNS address exposing over internet, usually this is disabled. So the best way to the solution is to check this to your VPN provider first.

About Windows update, a related update has been reported that could affect cisco VPN connection but not about DNS settings. You could check on that for reference.

https://social.technet.microsoft.com/Forums/en-US/ece4dfdf-6c47-45a2-a8fe-efe54a6116c4/windows-update-kb3023607-wireless-problems?forum=w8itprogeneral

Regards

D. Wu