Posts tagged ‘VPN Client’

How to join a Windows Domain using a VPN

There may be occasions where you need to join an off-site computer to an existing domain at a remote office.  Most often this would be in a situation such as a satellite office which is part of a larger corporate network and there is a site-to-site VPN in place.  Though a site-to-site VPN is by far the easiest way to join, it can be done using a Windows VPN client, which will be discussed further on in this article.  The primary problem encountered when joining the domain is DNS, but this is easily dealt with.

Joining the domain using a site-to-site VPN

  • Only 1 network adapter can be enabled on the PC joining the domain, and preferably a wired connection.  If any others exist such as a wireless card, disable until domain joined.  On occasion Bluetooth adapters will also conflict, so I recommend disabling them as well.
  • Configure the connecting PC’s network adapter either statically or through DHCP to point ONLY to the domain controller at the corporate office for DNS.  Do not add an alternate external DNS server such as an ISP or router as these will often respond first and name resolution will fail.
  • In the NIC configuration, under Internet Protocol Version 4 (TCP/IPv4) properties, click advanced, and under the DNS tab insert the corporate internal DNS suffix, such as CompanyDomain.local in the box entitled “DNS suffix for this connection”
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  • Then join the domain using the traditional method of Computer (formerly My Computer) | Properties | Change Settings |  Change | enter the internal domain name | click OK | and you should be prompted for credentials for an account authorized to do so, a Domain Admin account.  If the Domain Controller is a version of Small Business Server the SBS option to use  http://SBSname/connectcomputer  or http://connect most often will not work.  (more detail and screen shots for the joining the domain process can be found below in the using a VPN client section).
  • If you wish to simultaneously import an existing local user profile, you can use ProfWiz as outlined in the following link which will both join the domain and move the profile. Though the article references SBS, it can be used with any Windows Server Version.  https://blog.lan-tech.ca/2011/05/19/sbs-and-profwiz/

Joining the domain using a Windows VPN client

Joining a domain using a VPN client is a little more involved, but not complicated. This method may work with other VPN clients, so long as they have the option to connect to the VPN before logon, but this explanation uses only the Windows built-in VPN client.  Without the ability to connect before logon, there is very little advantage even if you can join the domain, as you would not actually be authenticating to the domain.  I will assume the server end, RRAS, is configured and working for VPN client connections.

  • Log on to the PC you wish to join the domain with a local administrator account
  • Only 1 network adapter can be enabled on the PC joining the domain, and preferably a wired connection.  If any others exist such as a wireless card, disable until domain joined.  On occasion Bluetooth adapters will also conflict, so I recommend disabling them as well.
  • Establish a VPN connection.  If not familiar with doing so:
    • From the network and sharing center choose “Set up a new connection or Network”
    • Select “Connect to a workplace”
    • Choose “Use my Internet connection (VPN)”
    • Enter the public facing FQDN of the corporate VPN server such as VPNserver.MyDomain.com and enter a friendly name for the connection, anything you like.  It is also very important to check the box “Allow other people to use this connection” as you will soon have a domain account which will require access to this VPN connection.
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    • Enter a User name, which ideally is the user that will be using the connection once joined to the domain, but can be any user name that is authorized to connect to the corporate network via VPN.  If you use a name other than the ultimate user of the PC they will simply have to change the user name during in the connection wizard, the first time they try to connect.  Enter the password and choose connect.  For security reasons I don’t recommend checking “Remember this password”.
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    • If prompted for a network type after connecting, choose “Work Network”.

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  • Presumably you were able to establish a connection.  However while connected if you did an NSlookup from a command line for the server name, you will see it fails. Try an NSlookup for the FQDN of the server, and it will succeed.  Thus, we need to configure DNS for the VPN clientbefore proceeding.
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    • Disconnect the VPN client
    • In the network connections window right click on the VPN/PPP connection and choose properties | Networking tab | highlight Internet Protocol Version 4 (TCP/IPv4) and choose properties | Advanced | DNS tab | and enter the IP of the corporate DNS server under DNS server addresses and the internal domain suffix such as MyDomain.local in the “DNS suffix for this connection box.  If admins need to connect to the remote client PC for administration by name check the box “register this connection’s address in DNS” but I would discourage this as the IP can change frequently and cause issues.  Also on the “IP Settings” tab leave the option “Use default gateway on remote network” checked, at least for now, so that all traffic is forced to the corporate network while the VPN is connected.
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  • Now you can try joining the domain
    • Connect the VPN client
    • Right click on “Computer” (formerly My Computer) and choose properties.
    • In the resulting window select “Change Settings”
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    • Slect “Change” again
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    • Enter the corporate internal Domain name, such as MyDomain.local in the Domain box and click OK
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    • You will be prompted for a domain account with privileges to join a PC to the domain, a Domain Admin.  Enter it and the password and you should receive a message advising you have been joined to the domain.  Be patient it takes a little longer as this is a slow link compared to the LAN.
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    • You now need to reboot the connecting PC.
  • In order to authenticate to the corporate network at logon and work as if on the corporate LAN, you need to connect the VPN before logging on to the PC.  When the PC reboots press Ctrl+Alt+Delete as you normally would, and then choose  “Switch User”
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    • You will then be presented with a new option, a little blue icon in the lower right corner.
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    • Clicking this allows you to choose to connect to the corporate network, by using the VPN.  After entering your credentials you will see the familiar VPN connection automatically start, it will connect, and you will be authenticated to the domain.
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    • Logon is a little slower of course due to the slow link, and the first time you connect it will have to set up the local domain profile.  If you make use of redirected my documents, offline files, or have a lot of group policies logon can take a very long time while they apply and sync.  If logon is too slow, you may want to review options available to the remote user.  You will note that if you now try nslookup <servername> works as it should.

Note:  If connecting from Windows 8, please see the following updated article:  https://blog.lan-tech.ca/2013/03/02/windows-8-connect-to-vpn-before-logon/

 

Depending on the performance of the VPN connection, it is sometimes necessary for the network administrator to “tweak” a few Group Policies for slow network detection. The following policies can assist with this:

Server 2008 / 2008 R2 / SBS 2008 / SBS 2011:
  • Computer Configuration | Policies | Administrative Templates | System | Group Policy | Group Policy slow link detection
  • Computer Configuration | Policies | Administrative Templates | System | Scripts | Run logon scripts synchronously
  • Computer Configuration | Policies | Administrative Templates | Network | Offline Files | Configure slow-link mode
  • Computer Configuration | Policies | Administrative Templates | Network | Offline Files | Configure slow link speed
Server 2003 / SBS 2003 / SBS 2003 R2:
  • Computer Configuration | Administrative Templates | System | Logon | Always wait for the network at computer startup and login
  • Computer Configuration | Administrative Templates | System | Group Policy | Group Policy slow link detection
  • Computer Configuration | Administrative Templates | System | Scripts | Run logon scripts synchronously
  • Computer Configuration | Administrative Templates | Network | Offline Files | Configure slow-link mode
  • Computer Configuration | Administrative Templates | Network | Offline Files | Configure slow link speed

 

Toast For Our Tables

Windows VPN Client Deployment

      subtitled: What happened to the SBS Connection Manager?

VPN name resolution is a common problem for many IT folk.  I have addressed in in previous blogs by manually configuring the VPN client to point to the corporate server for DNS, and adding the corporate domain suffix.  This is not practical as it has to be done on every computer on which the VPN client was configured.

Small Business Server 2003 had a very nice little wizard that would create a deployable VPN client called “Connection Manager” which contained server connection information and allowed for proper name resolution over the VPN.  Though the missing feature from subsequent SBS versions inspired this article, it can be used to create a deployable VPN client for any Windows Server.  The SBS wizard basically ran a mini version of a standard Windows tool called CMAK.

Firstly you need to install CMAK, the Connection Manager Administration Kit.  To do so, on a 2008 or newer server, open Server Manager under Administrative Tools, choose Features, and Add Features.  In the features wizard choose Connection Manager Administration Kit, and complete the wizard.

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Though there are many configurable options and features that can be added with CMAK, for the purposes of this article only the basics will be configured to allow for VPN name resolution, automatic installation, and to try to replicate the old SBS 2003 Connection Manager experience.  One of the additional advantages of the Connection Manager Client is it limits the options with which the client can “tinker”, thus reducing support calls and increasing security.

In this example CMAK is being run on a 64bit machine. The deployable VPN client created can only be used on other 64bit machines. If you need to deploy on a 32bit machine you will need to install and run CMAK on a 32bit computer/server.  CMAK may not available from the built-in windows options on older operating systems.  If so, it can be downloaded as part of the Windows Server 2003 Administration Tools Pack (32bit) http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=16770

Start The Connection Manager Administration Wizard from Administrative Tools, accept the UAC warning, click next, and select the O/S on which the client will be deployed, remembering the above warning about 32/64 bit.

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Select New Profile,

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Enter a ‘Friendly’ name for the connection and a file name (<9 characters) for the deployment package.

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Rather than cluttering this post with unnecessary images, accept the defaults on the next two pages, “do not add a realm name to the user name” and leave the merge profiles boxes empty. In the next window, as per the image below, check Phone book from this profile, always use the same VPN server, and insert the public FQDN or IP of the VPN server.

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Next highlight your new connection and choose edit.  Under General select Only IPv4 addresses.  If you like, for added security you can disable file and printer sharing, which blocks access to shares on the connecting client’s computer while connected to the VPN.

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Under IPv4 add the internal IP for your corporate DNS server.  If you have multiple corporate DNS servers you can add a second, and if you have WINS servers you can add those as well.  Do not add public DNS servers here.  I recommend checking “Make this connection the client’s default gateway” (disabling split-tunneling) which blocks access to to the client’s local LAN while connected to the VPN.  By doing so Internet access is actually made via the VPN, rather than through the local router.  One reason you may need to un-check this is it also blocks access to a local networked printer, i.e. one that is not physically attached to the connecting computer.  Leave “Use IP Header compression” checked.  Note that in a user created VPN client using the tools built into a Windows PC, the “default gateway” option can be changed.  When created with CMAK it cannot be changed.  This is intentional for security reasons.  Split-tunneling, allowing the client simultaneous local and remote network access, is considered a security risk.

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Under security you can leave the defaults or change to “Only use Point to Point Tunneling Protocol (PPTP)”.  If you are connecting to an old server it may also be necessary to also check CHAP authentication, but this is less secure than MS-CHAP v2, so only do so if absolutely necessary.  All 2008 and newer servers use MS-CHAP v2 by default.

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Under advanced add the internal corporate domain suffix.  Check “Register this connection’s DNS address in DNS” if for some reason LAN clients need to resolve the name of the remote computer.  I recommend not doing so if not needed as it adds unnecessary entries to DNS that may not be cleaned up if DNS scavenging is not properly configured.  Select OK, Next, and move on to the next window.

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We are not using “phone books” so uncheck “Automatically download phone book updates”

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From here accept all defaults in the next 4 windows; Configure Dial-up Networking, Specify Routing Tables, Configure Proxy Settings, and Add Custom Actions.

Note: it is assumed the server VPN configuration is basic, assigning IP’s in the same subnet for VPN clients as LAN clients, which is typical of SBS.  However, if the VPN clients are assigned addresses outside of the LAN subnet, and you want to access resources on the corporate LAN other than the VPN server, you will need to add a routing table file, on the “Specify Routing Tables” page, to have the route pushed out to VPN clients.

Though not necessary at all you may want to add a custom graphic or logo to the connection client. This is done on the “Display Custom Logon Bitmap” page followed by the ability to add a custom graphic in the phone book (list of connections), and on the 3rd related page you can choose to use  custom Icon for the deployed VPN connection.

Leave the “Include Custom Help File” as default, and under “Display Custom Support Information”.  You may want to add contact information. This is displayed on the VPN connection client where they enter their user name and password, when trying to establish a connection.

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Accept the defaults in the remaining windows; “Display a Custom License agreement” and “Install Additional Files…”.  In the final Window “Build the Connection Manager Profile and its Installation Program” leave Advanced uncheck, and assuming you do not wish to make any changes, click Next, and Finished.  The deployable package will be saved in a folder named profiles in the CMAK folder, the default location being: C:\Program Files\CMAK\Profiles\Windows 7 and Windows Vista\   You only need to copy the .exe file to the client computer, in this case AcmePkg.exe

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To configure the client, simply double click on the .exe file.  You will be prompted if you want the client to be available to all users or just the current user.

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Click OK, and wizard will complete, add a connection icon to the desktop, add the connection to task bar network icon………

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…….and launch the VPN client.

If you wish to connect enter the user name of a member of your VPN User group, their password, and internal domain name.  The domain name does not have to be present just to connect to the VPN, but in most cases if the PC is not domain joined, it needs to be there to access files using server names, rather than IP’s.

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You should now have access to resources on the remote server, assuming the VPN at the server end is properly configured, and you have the appropriate Share and NTFS/Security permissions on the server to do so.

If needed, I have bloged in the past about configuring the VPN server.

Configuring a Windows SBS 2003 as a RRAS/VPN Server

SBS 2011 Essentials – Configuring VPN access

Configuring a Windows 2003 RRAS/VPN Server with 1 network adapter

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