Specifications

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 3 Connecting on a LAN
Troubleshooting Connectivity to an Existing JACE Controller
3–18
Step 7 If you do not see the name of the JACE you are looking for (or any JACE), click the
the Back button of the Workgroup window and search in other listed workgroups and
domains for your JACE-NP. Otherwise, continue with the next step.
Step 8 Open a command prompt (see Procedure 2-12).
Step 9 Ping the JACE by name (see the “ping” section on page 2-20).
The ping command returns the IP address of the JACE you pinged.
Step 10 Connect to the JACE using the Admin Tool and change the incorrect network
settings as described in “Connecting a New JACE Controller,” page 3-9.
Method 2 (Complex)
If you cannot find the JACE by browsing the Windows network, you can use a
TCP/IP packet sniffer to capture IP packets. A packet sniffer analyzes network traffic
and provides a list of devices attempting to talk to one another, regardless of the
network address they are using. A sniffer can either be a hardware device or software
that runs on your PC.
Once you capture some packets, you can examine the capture and look for IP
addresses outside of the customer’s network range. Once you have a list of rogue IP
addresses you can attempt to connect to the hosts with either the Admin Tool or
NetMeeting.
Some things to note about using a packet sniffer:
• Packet sniffers can be used both for troubleshooting (as in this example) and
for malicious purposes. The customer’s IT department may have a strong
objection to you using one on their network, therefore, it is advisable to check
with them before using a sniffer on their network.
• The information presented by the sniffer is complex and may not be readily
understandable by a networking novice. Many IT departments regularly use
packet sniffers, therefore they may be able to get you the information that you
need.
If the IT department cannot help you, however, you can use the following procedure
as a guide to getting the information you want with a packet sniffer.
Procedure 3-6 Finding an IP address using a packet sniffer.
Step 1 Connect the TCP/IP packet sniffer to the same network as the JACE. The sniffer can
either be a hardware device, or your PC running packet capture software.
Step 2 Capture packets on the network for 5 minutes or longer.
Step 3 Examine the capture. Typically you will see a list of source IP addresses (the host
address that the packet was coming from) and destination IP addresses (what address
the packet was heading to).
Step 4 If possible in your sniffer, sort the list by the source IP address.