Remote Access to NetIntercept

To run NetIntercept remotely on another machine, you will need to ensure that both the NetIntercept machine and your remote machine are set up properly. This document outlines all the necessary steps to set up your systems to run properly.

• Setting up the NetIntercept Machine
• Setting up X and SSH on a Remote Windows Machine
• Setting up X and SSH on a Remote UNIX Machine (Linux/RedHat/FreeBSD)
• Issues with Fedora Core 3 and Remote Access to NetIntercept
• Additional X Servers and SSH Software

Setting up the NetIntercept Machine

To access a NetIntercept machine remotely via the CONTROL port, you first need to ensure the NetIntercept machine is set up properly. Follow the steps below.

1. On your NI box, make sure that /etc/ssh/sshd_config has the (uncommented) line:

   X11Forwarding yes
   

   Note: This should be how your system was configured when it came to you from Sandstorm.

2. Run /root/modrcconf.sh on your NI machine (as user root) to set up all the proper networking information (IP address, host name, etc.). For this web pages's example, the NI machine will be called nibox.yoursite.com, and the IP address will be 123.123.123.123
3. Connect the appropriate network cable is to the Control interface on the NI machine.

Setting up X and SSH on a Remote Windows Machine

Follow these steps to set up an X Window Server on a machine running Microsoft Windows(r):

1. Obtain an X Window Server Program and install it according to the product manufacturer's instructions. A list of these programs can be found on our NetIntercept X Servers web page.
2. Start the X Window Server (Sometimes called X server. The program icon will be present in the computer's task bar.

3. Obtain an SSH client program and install it according to the product manufacturer's instructions. A list of these programs can be found on our NetIntercept X Servers web page, the SSH Client programs are at the bottom of that page.
4. Run your SSH client.
5. Configure the SSH client to contact the IP address given to the NI machine, using X forwarding (sometimes called X11 forwarding). The forwarding option is often found under "SSH Options" in the client software. Contact your system administrator for help, if necessary.
6. Enter your remote machine's IP address, followed by ":0.0" (e.g.,10.4.2.10:0.0), as the X display location, if your SSH client requires that information.
7. Connect to the NI machine as user ni using the SSH client. Enter the ni user's password when prompted. The NetIntercept user interface will start automatically. The Traffic tab in the user interface should display a graph of captured traffic.

Setting up X and SSH on a Remote UNIX Machine (Linux/RedHat/FreeBSD)

1. Install X on the remote machine if it is not already present. There are instructions on how to do this at the xfree86.org site.
2. Start X on the remote machine. There are two ways to do this:
   • Automatically at reboot: in /etc/ttys, ensure this line is present:
     

     ttyv8 /usr/X11R6/bin/xdm -nodaemon xterm on secure

     Note: This command needs to have a specified tty. If you are already using ttyv8 for something, you may change that to a different number.

   • Manually: run the command:

     /usr/X11R6/bin/startx

3. On the remote machine, modify your file /etc/sshconfig to have the following (uncommented) line:
   

   ForwardX11 yes

4. Type either of the following two commands at a shell prompt to get remote access to the NI machine:

   • ssh ni@nibox.yoursite.com
   • ssh ni@123.123.123.123

5. Enter the ni user's password when prompted. The NetIntercept user interface will start automatically. The Traffic tab in the user interface should display a graph of captured traffic.
6. You will be prompted for the user password. Type it in, and the NI user interface should appear.

Issues with Fedora Core 3 and Remote Access to NetIntercept

Fedora Core 3 contains OpenSSH 3.9, which is no longer configured to request X11 forwarding by default when connecting to servers. It will alter existing system settings to remove this option if it has previously been set. To enable X11 forwarding, the -X or -Y option must be specified, or the ForwardX11 option must be enabled in the /etc/ssh/ssh_config file.

Furthermore, the behavior of SSH clients that are invoked with the -X flag has changed. Now, X11 forwarding is performed so that applications run as untrusted clients by default. Previously, X11 forwarding was performed so that applications always ran as trusted clients. Some applications may not function properly when run as untrusted clients. To forward X11 so that applications are run as trusted clients, invoke ssh with the -Y flag instead of the -X flag, or put the line set ForwardX11Trusted in the /etc/ssh/ssh_config file.

In summary, if you are running Fedora Core 3 (i.e., OpenSSH 3.9) on the remove machine, make the following changes on it:

1. Put the following two lines in /etc/ssh/ssh_config:
   • ForwardX11 yes
   • ForwardX11Trusted yes
2. Run your ssh session with the following command line: ssh -Y ni@

Note:The /etc/ssh/ssh_config file referenced above is a machine-wide configuration file. If you are sharing the use of the remote machine wtih other users, you may wish to make those changed in ~/.ssh/config instead. OpenSSH 3.9 requires that the ~/.ssh/config file be owned by the owner of ~/ (e.g. the user) and that the protection be 0600 (unreadable by anyone but the user).

Additional X Servers and SSH Software

Additional X servers can be found on our NetIntercept X Servers web page.

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