Question

SBS2003, ISA2004

Asked by: GillianBeaumontLegal

I am now completely stumped with a VPN connection.

I have SBS2003 with ISA2006 at one end (Branch Office), and SBS2003/ISA2004 (Head Office) at the other. I can create a site-to-site connection from the Head Office to the Branch Office - works a treat once approriate rules were put in place. However, no matter what I do or how hard I try, I cannot get a connection through from the Branch to the Head Office (which is the one I need.)

Whenever I dial (either a RAS connection or by using the site-to-site creation wizard) the Head Office, I get an Error 628 disconnect. On the other hand, if I dial from a client at the Head office to the Head Office server, I can get a connection. I figure at lease the VPN end of the server is working.

I can connect from Branch to Home, so I guess I understand what I am trying to do.

The variables therefore seem to be the routers on either end. I have used the PPTP passthrough and checked the Port 1723 and GRE are opened. Using the Microsoft Windows Network Monitor, I can see the GRE packets at the Head Office Network, so I don't think I am blocking them. Just to be safe, I put the server in the DMZ in the hope that this would work. No luck.

I can telnet 1723, so I know that it is open. ISA logs show the packets being received, and then the connection is closed.

I have tried multiple users, ensuring that all are checked for dial in access.

Experience tells me that I am doing something really dumb, and have just spent the last how many hours going nowhere.

The setup is essentially:

Head Office
Private Adapater - 192.168.0.0-192.168.0.255 (server 192.168.0.21)
Public Adapter: 10.0.0.1 (server 10.0.0.21)
Router: Dlink DSL G604T - it makes the ADSL connection etc

Branch Office
Private Adapter: 192.168.1.0 - 192.168.1.255 (server 192.168.1.21)
Public Adapater: 172.16.0.0 - 172.16.0.255 (server 172.16.0.1)

The biggest clue I have so far is messed up routing. When I look at the public network on the Head Office Side, and I chose Add Adapter, I would have thought I would get only 10.0.0.0-10.0.0.255 plus loopback addresses etc. Instead, I get just about every address known to the universe. If I remove them and just use the 10.0.0.0 range, I lose external access to my web server on ports 80 and 443.
Router: billion 7404VGP 172.16.0.1

I would grately welcome any assistance possible in working out what on earth to do next.

Thanks

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Asked On
2007-09-04 at 21:11:49ID22807131
Tags

SBS2003

,

ISA2004

Topics

MS Forefront-ISA

,

Virtual Private Networking (VPN)

,

SBS Small Business Server

Participating Experts
2
Points
500
Comments
13

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Answers

 

by: TechSoEasyPosted on 2007-09-05 at 06:44:07ID: 19832224

Can you establish a VPN connection to the Head office from somewhere other than the branch office?

Jeff
TechSoEasy

 

by: GillianBeaumontLegalPosted on 2007-09-06 at 17:29:58ID: 19844649

I have made some progress in eliminating the source.

1. I can connect to the Head Office VPN internally.
2. I can connect to the Head Office VPN from a non branch office network
3. I can connect to the Head Office VPN is I bypass the Branch Office Server and connect directly from the ADSL router (ie bypass everthing on the network - I guess this is effectively then another external network)
But
4. I cannot connect from the Branch Office Server
5. If I shut down ISA, I still cannot connect

If I create VPN rules on the Branch Office ISA Server that do not use the PPTP filter (ie just allow IP47 and 1743) I can see the IP packets being dropped.
If I enable the PPTP filter, I don't get a message that they are being dropped, only a failed connection.

Currently therefore I figure

1. The Head Office Server is fine.
2. The External ADSL modem/router is fine.
3. Something either on the server (independed of ISA) or the network card itself is blocking the packets.

Grateful for any observations.

Thanks

Jonathan

 

by: TechSoEasyPosted on 2007-09-06 at 23:03:59ID: 19845688

"ie just allow IP47 and 1743"

Just to clarify here... GRE is not PORT 47.  And I'm sure that you meant 1723 not 1743.

Your initial comments seemed to understand how to deal with GRE Protocol 47, but perhaps you should review this KB article for how to write the rule:
http://support.microsoft.com/kb/923836

Jeff
TechSoEasy

 

by: GillianBeaumontLegalPosted on 2007-09-09 at 00:52:06ID: 19856089

A further update.

Because I can dial from a client directly connected to the Billion Router, I figure I have eliminated that.

In order to rule out the network cards, I have swaped the two cards in the SBS2003 server and reconfigured. No change.

I then deleted ISA, and had no problem at all dialing the connection.

I have reinstalled ISA, and setup the various passthrough rules (yes, IP47, not port 47), and yes, opened port 1723 (not 1743 as I said in the previous post.) and get blocked again.

I figure therefore my problem must be some kind of double-NAT  between the ISA box, the Billion Router and the Head Office.

ISA is reporting the local packets being sent from the internal network, but the Head Office server sees tham as coming from the Public Address of the router.

Given that I can get through the Router without using the ISA box, I figure I am down to a NAT issue.

I am now getting an error message on the ISA server which I wasn't getting before

"You were not connected because a duplicate name exists on the network. Go to System in Control Panel to change the computer name and try again 0x80070034"

I can't understand what the error is trying to say - which name is dubplicated and where. The error number seems to point to a DNS error, but I can't find any duplication.

Hence I return to my NAT issue.

HELLLLLLLLLLLP!!!!!!!!

 

by: TechSoEasyPosted on 2007-09-09 at 10:51:35ID: 19857499

Well, just FYI, one way to accomplish this is to follow the steps outlined in this blog post:  http://sbsurl.com/vpntunnel

However, if you want help in figuring out what's happening with your current scenario... I'll give it a shot.

Could you please provide a COMPLETE ipconfig /all from both servers so I can take a look at all of the networking settings on each?

Jeff
TechSoEasy

 

by: GillianBeaumontLegalPosted on 2007-09-09 at 16:44:36ID: 19858294

Thanks for your continued efforts Jeff.

Following one of your previous posts about network configuration, I think I have this correct. Here is the ipconfig /all

Windows IP Configuration
   Host Name . . . . . . . . . . . . : server
   Primary Dns Suffix  . . . . . . . : beaumontfamily.local
   Node Type . . . . . . . . . . . . : Unknown
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : Yes
   DNS Suffix Search List. . . . . . : beaumontfamily.local

Ethernet adapter Internal 192.168.1.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet NIC
   Physical Address. . . . . . . . . : 00-1B-11-65-F1-60
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.1.21
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 192.168.1.21
   Primary WINS Server . . . . . . . : 192.168.1.21

Ethernet adapter External 172.16.0.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet
   Physical Address. . . . . . . . . : 00-0B-CD-E7-73-62
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 172.16.0.21
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 172.16.0.1
   DNS Servers . . . . . . . . . . . : 192.168.1.21
   NetBIOS over Tcpip. . . . . . . . : Disabled


Thanks

 

by: GillianBeaumontLegalPosted on 2007-09-09 at 16:51:34ID: 19858309

Jeff

I am now getting the following message on the ISA Server regarding the IP47

Failed Connection Attempt SERVER 10/09/2007 9:46:57 AM
Log type: Firewall service
Status: You were not connected because a duplicate name exists on the network. Go to System in Control Panel to change the computer name and try again.  
Rule: VPN Out
Source: Local Host ( 172.16.0.21:0)
Destination: External ( 60.229.248.126:0)
Protocol: IP47
User:  
 Additional information
Number of bytes sent: 0 Number of bytes received: 0
Processing time: 0ms Original Client IP: 172.16.0.21
Client agent:
 
"a duplicate name exists on the network" - I assume the remote network
"a duplicate name exists on the network" - I assume this must be the Branch Office Server

Firstly, I thought the VPN was still IP only at this stage  - what could names have to do with it
Secondly, there is no device with an identical name on either network.

Remember, that if I remove ISA from the equation, I can connect.

I don't know if I am getting closer to resolving this, or closer to killing it!

 

by: TechSoEasyPosted on 2007-09-10 at 10:11:33ID: 19862437

I'll be happy to comment on that if you can also post the IPCONFIG from the branch server as requested above.  Thanks.

Jeff
TechSoEasy

 

by: GillianBeaumontLegalPosted on 2007-09-10 at 15:56:40ID: 19864887

This one is the Head Office - the Branch Office is the first one.

Windows IP Configuration
   Host Name . . . . . . . . . . . . : gbr-sbsrv
   Primary Dns Suffix  . . . . . . . : GillianBeaumont.local
   Node Type . . . . . . . . . . . . : Unknown
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : Yes
   DNS Suffix Search List. . . . . . : gillianbeaumont.local

PPP adapter RAS Server (Dial In) Interface:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface
   Physical Address. . . . . . . . . : 00-53-45-00-00-00
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.0.32
   Subnet Mask . . . . . . . . . . . : 255.255.255.255
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Disabled

Ethernet adapter Local Connection 192.168.0.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : HP NC320i PCIe Gigabit Server Adapter
   Physical Address. . . . . . . . . : 00-17-A4-36-6E-C7
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.0.21
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 192.168.0.21
   Primary WINS Server . . . . . . . : 192.168.0.21

Ethernet adapter Public Connection 10.0.0.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : HP NC1020 Gigabit Server Adapter 32 PCI
   Physical Address. . . . . . . . . : 00-14-38-B9-53-75
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 10.0.0.21
   Subnet Mask . . . . . . . . . . . : 255.0.0.0
   Default Gateway . . . . . . . . . : 10.0.0.1
   DNS Servers . . . . . . . . . . . : 192.168.0.21
   NetBIOS over Tcpip. . . . . . . . : Disabled


*************************
I hope this provides some further insight.

Thanks

 

by: TechSoEasyPosted on 2007-09-11 at 16:50:56ID: 19872980

Okay... your IPCONFIG from beaumontfamily.local was run without having a VPN connection. (which is expected since you say you can't make that connection)  But if you could... your IPCONFIG would include an entry for the connection and then it would look something like this:

Windows IP Configuration
   Host Name . . . . . . . . . . . . : server
   Primary Dns Suffix  . . . . . . . : beaumontfamily.local
   Node Type . . . . . . . . . . . . : Unknown
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : Yes
   DNS Suffix Search List. . . . . . : beaumontfamily.local

Ethernet adapter Internal 192.168.1.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Realtek RTL8139 Family PCI Fast Ethernet NIC
   Physical Address. . . . . . . . . : 00-1B-11-65-F1-60
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.1.21
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 192.168.1.21
   Primary WINS Server . . . . . . . : 192.168.1.21

Ethernet adapter External 172.16.0.21:
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet
   Physical Address. . . . . . . . . : 00-0B-CD-E7-73-62
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 172.16.0.21
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 172.16.0.1
   DNS Servers . . . . . . . . . . . : 192.168.1.21
   NetBIOS over Tcpip. . . . . . . . : Disabled


PPP adapter gillianbeaumont:

    Connection-specific DNS Suffix  . :
    Description . . . . . . . . . . . : WAN (PPP/SLIP) Interface
    Physical Address. . . . . . . . . : 00-53-45-00-00-00
    Dhcp Enabled. . . . . . . . . . . : No
    IP Address. . . . . . . . . . . . : 192.168.0.10
    Subnet Mask . . . . . . . . . . . : 255.255.255.255
    Default Gateway . . . . . . . . . : 192.168.0.10
    DNS Servers . . . . . . . . . . . : 192.168.0.21
    Primary WINS Server . . . . . . . : 192.168.0.21
       
What you will see by this is that you would have TWO DNS Servers that are being used.  Both of those servers have a CNAME entry for COMPANYWEB, which is what I think is causing the "duplicate name" error.  You should be able to resolve this with a registry entry to disable "strict name checking".  The instructions for that are here:  http://www.jsifaq.com/SF/Tips/Tip.aspx?id=8062

That should work... but if not let me know.

Even though this is probably not causing your problem, I would add that I think you complicated things by trying to use different subnet classes.  Perhaps because you thought that would have less of a chance for conflict?  Without delving into your routing too much, I'd first suggest that you simplify things by using only Class C subnets.  This means that you would always use a subnet mask of 255.255.255.0 whether you use 192.168.x.x or 172.16.x.x or 10.x.x.x doesn't really matter, but using a consistent format will help you to better see how all this works together, but most importantly... you should only be using 255.255.255.0 for all your subnet masks.

Jeff
TechSoEasy

 

by: TechSoEasyPosted on 2007-09-11 at 16:51:58ID: 19872984

FYI, removing one of the CNAME records is not an option... you'll break the CEICW if you do that.

Jeff
TechSoEasy

 

by: GillianBeaumontLegalPosted on 2007-09-14 at 00:04:33ID: 19889477

Thanks for your help.

I have now got uni-directional VPN working. It appears that one of the problems was the Billion Router. Changing it to a D-Link got me though straight away.

I was also told that it is not possible to do complete site-to-site (ie bi-directional) PPTP VPN's when you are behind ADSL routers, unless they are in bridge mode and the fixed IP address is on the ISA box, rather than the router. I can't quite see how this could be a problem. Surely if I can get through in 1 direction, I should be able to go both ways.

Anyway, thanks for the help. I will consider it resoved with Jeff's help.

Now on to my next issue - SQL authentication over the VPN.

 

by: amrlotusPosted on 2008-03-29 at 16:10:40ID: 21238532

can you please inform us of what d-link router you got instead of the billion 7404vgp
that of course support dial in VPN

20120131-EE-VQP-002

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