Passive Monitoring Key Points
 Highly secure compared to SNMP and RMON
 Provides the highest detail of monitoring
 In practice, all network problems can be discovered
and solved using passive packet sniffer technology.
 Stealth nature cannot be detected by other tools.

To whom is it useful?
 useful to…
 Network Administrators
 Application Developers
 Network Auditors
 Students.
 Everyday “Joe” who would like to know
what is happening in his network

Unique Features…
 Display in real time:
 General traffic information
 Total network traffic and bandwidth utilization
 Graph for utilization and distribution
 Detailed breakdown of packets,
raw and decoded with optional filtering
 Decode major protocols and sub-protocols
 Highly secure compared to SNMP and RMON

Common Usage
 Abnormal or Suspicious Activities Monitoring
 Intrusion Monitoring
 Bandwidth Monitoring
 Critical Node Monitoring
 Application Monitoring
 Data Forensic (Packet Analysis)
 Real time / offline Analysis.
 Network Anomaly Detection.
 Top Usage.

Bandwidth monitoring
 Network Usage Statistic (General)

Critical node monitoring
 Network Usage Statistic (Single)

 Network Trace (Single)

 Intelligent Address Book

Protocol Monitoring
 Network Charts (Protocol Distribution ->
Network Layer and IP-based)

Application Monitoring
Network Charts (Protocol Distribution ->
Application Layer Distribution)

Packet Analysis
 Network Analyzer (Capture and Decode)

Reporting Toolkit Interface
Daily, Weekly, Monthly Reporting
Control Window

Network analysis fundamentals
Ethernet
 A network card is an Ethernet adapter
 Each Ethernet adapter is globally assigned a
unique hardware address.
 It’s a 48-bit binary number generally written as
12 hexadecimal digits
Ex: (00:e0:30:3f:21:b6)
 MAC addresses are used for data communication on a network
 Unicast
 Multicast
 Broadcast The destination address of all 1s
(ff:ff:ff:ff:ff:ff in hexadecimal)
Ethernet II Frame

Hubs
A hub is a device that runs at the physical layer of the OSI model and allows
Ethernet networks to be easily expanded.
When devices are connected to a hub, they hear everything that the other
devices attached to the hub are sending, whether the data is destined for
them or not.

Switches and Bridging
 Bridges and switches are both intelligent
devices that divide a network into collision
domains to improve performance.
 A collision domain is defined as a single
CSMA/CD network in which there will be a
collision if two stations attached to the system
transmit at the same time.

Deployment
 A Technician’s Tool Kit for Troubleshooting:
 a laptop with j-Portable
 Some straight-through and cross-over cables
 a mini-hub
 For Constant Monitoring
 A dedicated monitoring machine installed with j-enterprise
 Dedicated hub / mirrored switch for monitoring
The point to plug in the monitoring machine
depends on what we want to monitor.

 “Over the wire” monitoring

Monitoring network applications with j-
Portable
correct placement to capture specific communication

 Further steps to be taken will be based
on these questions:
 What do we want to monitor?
 Where do we want to monitor?
 What do we want to look for?

Things to monitor
 To monitor network applications/software
 To monitor performance of the network
 To analyze network data & issues
 To detect security breaches

Common Cases
Scenario: You are developing a client server application. You need to
troubleshoot it. Did the packets actually get transmitted by the client to the
server?
Scenario: You have installed a web based application server.
Is the traffic to/from it as it should be?
Use Capture Decode to see actual traffic,
use Netrace to see actual connections

Common Cases…
2. How we can monitor network performance ?
Scenario:You have a network gateway and would like to
monitor and know the percentage of utilization of your
Internet access traffic.
Use Network Statistics to view actual usage statistics,
use Graph to view distributions by protocols.
For history, use Reporting Tool.
Bandwidth utilization, use Node Monitor

Common Cases…
3. How to perform analysis of network data?
Scenario: A worm is existent in your network
Scenario: ARP poisoning is being actively done
on the local network
Capture and Decode to look for abnormal traffic.
Pinpoint of the culprit can be done based on the
Address Book data.

Common Cases…
4. When can I use tools to analyze network issues?
Scenario: A user complains “the network is slow”
Use Statistical View to see if the network is congested,
use Capture and Decode to view traffic and
to pinpoint sources of problem.

Common Cases…
5. How can I gain better network security?
Scenario: An outsider is trying to scan machines on my
network.
Netrace will tell me the sources and destinations
of those scans.

Common Cases…
6. How can I optimize my network with j-Portable?
Scenario: Your newly installed network printer is running
AppleTalk and IPX but no one else is using it.
Scenario: One of your routers is running unneeded
IGMP or BGP protocols
j-Portable:
Use Capture & Decode and view network traffic,
Filter for single address. Look for unneeded traffic.
Make the needed adjustments on those devices.

Problem Detection …..
1. ARP storm detection
 Monitor each host for certain time.
 Each host should send a reasonable amount of
ARP packet to resolve its IP address.
 The host is sending an ARP storm, if it
continuously send ARP requests to certain IPs
or even to a range of IPs. ( broadcast normally)

Problem Detection …..
3. Worm detection
 AV maintain a DB of all known worm signatures.
 The moment av start the capturing process, it will sniff
each packet and apply all filters on these packets.
 The decoder will decode each of the captured and
filtered traffic.
 The dissector will extract the payload depend on the
traffic type.
 The payload then are matched to the DB of signatures.
 If the match return 1, then worm detected.

Network monotoring

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