This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

SSL VPN issue with DNS on Windows 10

Some (but not all) of our Windows 10 users are having a DNS problem when connecting to our local internal network via SSL VPN.

The IP range for our internal network is 192.168.31.0/24. SSL VPN users all get addresses in the 10.242.2.0/24 range.

Our UTM provides DNS services for local network. We have several internal servers which are ONLY accessible from the LAN, or from an SSL VPN connection to the LAN. They have only private IP addresses.

Here's the problem. Our Windows 10 users (again, only some of them) connect successfully to the VPN. They then try to connect to one of our local servers via an IP name (for example, "projectserver.mydomain.com" which points to, for example, 192.168.31.4). The specific error varies, depending on what application they're using, but basically, it's an "NXDOMAIN" error.

The error occurs because, even though they're connected to the VPN, their PC has prioritized their regular (non-VPN) network connection. So when an app on their computer requests a domain name address, the request goes to their normal internet connection to a public DNS server, not over the VPN to our UTM's DNS server. The UTM knows about "projectserver.mydomain.com", but the public DNS server does not, hence the error.

If the user happens to know the numeric IP address (say, 192.168.31.4), they can type that in instead of projectserver.mydomain.com, and it works.

In Windows 7 and earlier, this was never a problem for us. If the SSL VPN connection was active, it was always prioritized and got all DNS requests. With Windows 10, it doesn't always work that way. This may well be a Windows problem and not a UTM problem, but either way, there must surely be a fix by now. Does any one have any suggestions?



This thread was automatically locked due to age.
Parents
  • Hi, Bruce, and welcome to the UTM Community!

    Fellow member Twister5800 was the first (before Sophos!) to have solved this problem.

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • Hi Bob,

    this thread is now one year old and I still have that same issue, yes me - the UTM admin himself! :-)  I just installed the latest client from the Portal but still the problem persists. Can you confirm this? Should I switch to the OpenVPN client?

     

    It looks like this on the command line:

    > ping xy.fqdn.com
    Ping request could not find host xy.fqdn.com. Please check the name and try again.
    > nslookup xy.fqdn.com
    Server: dnsserver.fqdn.com
    Address: 10.2.1.2
    Name: xy.fqdn.com
    Address: 10.2.1.72
    > ping xy.fqdn.com
    Ping request could not find host xy.fqdn.com. Please check the name and try again.
    > nslookup xy
    Server: dnsserver.fqdn.com
    Address: 10.2.1.2
    Name: xy.fqdn.com
    Address: 10.2.1.72
    > ping xy
    Ping request could not find host xy.fqdn.com. Please check the name and try again.
  • Just a hint: I think it is better if I use a network cable instead of my wireless network but that may be a coincidence.

  • I don't know as I cannot reproduce this behavior on 9.409.

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
Reply
  • I don't know as I cannot reproduce this behavior on 9.409.

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
Children
No Data