Solved

Need help with authentication problem for VPN users

Posted on 2008-06-26
2
261 Views
Last Modified: 2010-05-18
OK, I'll try to be as descriptive as possible here.  I have users that are VPN home users that cannot authenticate to Active Directory.  We are using these Proventia VPN appliances at the users locations.

Our AD topology here is hub and spoke.  With our home office being the hub, and all the remote offices (not the home VPN users) being spokes with DCs at all the spoke locations, as well as DCs at the main office.

Due to security restrictions, these VPN users are only allowed to communicate with the Hub home office location, and all communication to spokes is restricted.

Make sense?

So, here's my understanding of AD authentication.  First a PC looks for a DC on its local subnet (There are none on the VPN users subnets) If it fails to find a local DC, it does an LDAP query to DNS to locate a DC.  Once a non preffered DC responds, it tells the PC its AD site information, and then caches in what preffered DC it should be using.

So the PC successfully queries DNS for a list of DCs, but since communcation to spoke DCs is shut off, these DCs do not respond, and the PC sits forever at a login screen and never receives its site information.

Placing a DC on the local subnet for the VPN users is not possible, since each PC is on its own subnet.

My question is, is there a way to force a PC to only look at specific DCs during initial authentication before it is able to grab its site information from AD?
0
Comment
Question by:achernob
2 Comments
 
LVL 30

Accepted Solution

by:
LauraEHunterMVP earned 500 total points
ID: 21876082
Can you supernet the hub site to include the IP address range that you are providing to your VPN clients?  That's how I usually do it.  HUBSITE contains the IP ranges that physically correspond to that location, as well as the to Class C that I've allocated for incoming VPN connections. That way the VPN clients are -in- the HUBSITE, from AD's perspective.

If this isn't an option, then you're not going to have much luck - there isn't any good way to force an AD client to use a specific DC for auth.  AD expects all DCs to be similarly "available", so if you start muckling around with DENY ACLs on routers and VPN connections, you're going to run into exactly the type of situation that you're describing.
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Is your Office 365 signature not working the way you want it to? Are signature updates taking up too much of your time? Let's run through the most common problems that an IT administrator can encounter when dealing with Office 365 email signatures.
This article explains the steps required to use the default Photos screensaver to display branding/corporate images
This tutorial will walk an individual through the process of transferring the five major, necessary Active Directory Roles, commonly referred to as the FSMO roles to another domain controller. Log onto the new domain controller with a user account t…
This video shows how to use Hyena, from SystemTools Software, to bulk import 100 user accounts from an external text file. View in 1080p for best video quality.

789 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question