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I connect to a range of servers hosted by one provider via a VPN. I can connect to the VPN fine, however when I then go and try and connect to the server(s) it fails.

A NAT'ed IP address that has worked up until today, has stopped working either via SSH/SFTP.

As you can see below, if I try and ping the IP then it responds with Destination host unreachable, but, for some reason it says the reply is from 192.168.0.8?

If it enter this IP address in my browser, I get nothing. Where is this IP coming from and is there any good reason why I cannot access the IP I am trying to ping?

C:\Users\crmpicco>ping 172.26.100.x

Pinging 172.26.100.x with 32 bytes of data:
Reply from 192.168.0.8: Destination host unreachable.
Reply from 192.168.0.8: Destination host unreachable.
Reply from 192.168.0.8: Destination host unreachable.
Reply from 192.168.0.8: Destination host unreachable.

Ping statistics for 172.26.100.x:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

I have the VPN remote host address of 80.75.67.x, which shows me as being connected. But i'm unsure if there is a config issue at the server side or my end that has caused this issue?

I have had some recent Win7 (automatic) updates, but it's hard to tell if that's caused this problem.

This is my output from arp:

C:\Users\crmpicco>arp -a

Interface: 192.168.0.8 --- 0xe
  Internet Address      Physical Address      Type
  192.168.0.1           00-18-4d-b9-68-5e     dynami
  192.168.0.6           00-f4-b9-68-0c-9a     dynami
  192.168.0.7           08-00-27-f2-9f-d6     dynami
  192.168.0.255         ff-ff-ff-ff-ff-ff     static
  224.0.0.22            01-00-5e-00-00-16     static
  224.0.0.251           01-00-5e-00-00-fb     static
  224.0.0.252           01-00-5e-00-00-fc     static
  239.255.255.250       01-00-5e-7f-ff-fa     static
  255.255.255.255       ff-ff-ff-ff-ff-ff     static

Interface: 192.168.56.1 --- 0x15
  Internet Address      Physical Address      Type
  192.168.56.255        ff-ff-ff-ff-ff-ff     static
  224.0.0.22            01-00-5e-00-00-16     static
  224.0.0.251           01-00-5e-00-00-fb     static
  224.0.0.252           01-00-5e-00-00-fc     static
  255.255.255.255       ff-ff-ff-ff-ff-ff     static

This is the output from a ipconfig /all:

C:\Users\crmpicco>ipconfig /all

Windows IP Configuration

   Host Name . . . . . . . . . . . . : RS0000225
   Primary Dns Suffix  . . . . . . . : london.crmpicco.local
   Node Type . . . . . . . . . . . . : Broadcast
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : london.crmpicco.local
                                       crmpicco.local

Wireless LAN adapter Wireless Network Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Dell Wireless 1701 802.11b/g/n
   Physical Address. . . . . . . . . : E4-D5-3D-F0-55-DD
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::5874:fe3d:aa4e:7fde%14(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.0.8(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : 11 June 2012 15:22:16
   Lease Expires . . . . . . . . . . : 12 June 2012 17:05:24
   Default Gateway . . . . . . . . . : 192.168.0.1
   DHCP Server . . . . . . . . . . . : 192.168.0.1
   DHCPv6 IAID . . . . . . . . . . . : 367318333
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-CB-EF-F1-24-B6-FD-1E-5D-0

   DNS Servers . . . . . . . . . . . : 192.168.0.1
   NetBIOS over Tcpip. . . . . . . . : Disabled

Ethernet adapter Local Area Connection:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
   Physical Address. . . . . . . . . : 24-B6-FD-1E-5D-05
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Ethernet adapter VirtualBox Host-Only Network:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : VirtualBox Host-Only Ethernet Adapter
   Physical Address. . . . . . . . . : 08-00-27-00-FC-8B
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::48a0:3a6e:99bd:7e8e%21(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.56.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 621281319
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-CB-EF-F1-24-B6-FD-1E-5D-0

   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.{8AA9F4BC-3CC6-43B5-93ED-12D4D8AD8E80}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{EF5EDA40-742E-4189-A57F-7ABB13C850B7}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{F2396A20-64D3-4280-8177-A88A013E5E8A}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
share|improve this question
    
What is your ip (on vpn interface)? Netmask? Server's ip/mask? What is NATted to what? Your routing table? Any firewalls anywhere? –  mulaz Jun 11 '12 at 14:53
    
The remote host of the VPN is 80.75.67.x - I have that! I am using Windows 7, so I am not familiar with the networking and routing mechanisims on this OS unfortunately. What would you suggest the 192.168.0.8 is? –  crmpicco Jun 11 '12 at 15:00
    
The NAT is a bit of a red herring, since you are connecting to a VPN it should make your computer a part of their local network. Did you run the ipconfig while you were connected to VPN? Can you also do a route print while you're connected to the VPN? A "host unreachable" means that based on the device's routing table it's not possible to reach that host. If I had a guess, I'd think you're not fully connected to the VPN or the VPN has changed somehow and you should contact the provider. 192.168.0.8 is your local nic, it's saying that your computer doesn't know where to send traffic for 172 –  Snowburnt Apr 16 '13 at 16:01
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1 Answer 1

My understanding is that the message, "Host Unreachable," can be sent back from a network interface, as would be expected, when it has determined the host address is unreachable.

In this case it looks like this message is coming back from your own network interface/network connection, that is to say, while the VPN's address may be 80.75.67.X, your NAT'd IP address (if you are indeed properly connected to the VPN) is 192.168.0.8. Based on my relatively limited knowledge of VPNs (I'm still coming to learn the intricacies), this seems incorrect.

You can see this when you called arp -a, it lists two interfaces, both belonging to you, one of which is the 192.168.0.8.

Can you provide the output from "ipconfig /all"?

To me it looks like your connection to the VPN might not be correct and you might still be on your local network with that 192.168 address (and since your destination/server address is in the 172.26 address space). Can you access any other resources on the VPN?

share|improve this answer
    
I cannot access any other resource on the VPN. I have just updated my question with the output from ipconfig /all. –  crmpicco Jun 11 '12 at 16:43
    
Right, so you can see right there that your IP address for your machine is 192.168.0.8, so the error is telling you that your local interface cannot connect to 172.26.X.X, simply because it doesn't know how to get to that IP address. To me, that tells me your VPN connection may not be configured properly. At the very least, it tells you that when trying to reach that server's address, it's attempting to do so over your local LAN interface. –  John K Jun 11 '12 at 16:45
    
So the 192.168.0.8 address is my physical machine and definately not my wireless router? When you say the VPN connection is not configured properly do you mean at my end (i'm using Shrew Soft VPN Connect) or at the server end? I do not maintain or control the VPN, so this is quite important. –  crmpicco Jun 11 '12 at 17:08
    
That's correct, your physical machine's IP address is 192.168.0.8, while your router, presumably, is your gateway, which as is typical, is listed as 192.168.0.1. As far as your VPN connection, I would think it's more likely a configuration problem on your laptop. I don't have any experience with Schrew Soft; do you have any icon, or indication that you're connected properly? –  John K Jun 11 '12 at 17:14
    
OK. I have had some Windows 7 updates recently, so i'll try disabling my software firewall on my Windows machine and see if that makes any difference. I have a pretty old wireless router so I can't imagine that there has been any updates pushed to the device without my confirmation, surely? –  crmpicco Jun 12 '12 at 10:35
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