The Working Person’s Sniffer
What won’t it monitor?
Sniffers are like opinions—seems like everyone’s got one. There are thousands
of sniffers on the market, from the very basic to the extremely complex;
Observer 8.1 is somewhere in the middle. I found Observer to be well laid
out. It was easy to navigate via the menu bar and toolbar (see Figure).
If you’re familiar with other sniffer products, you’ll probably feel right
at home with Observer. If you aren’t familiar with using sniffers, Observer
can be a little daunting. Observer is a fairly advanced protocol analyzer
and monitoring tool, and the manual encompasses 578 pages (now that’s
Observer supports Windows 98, Me, NT, 2000 or XP. It requires at least
a Pentium 400 with 64MB of RAM and a monitor with 800x600 resolution.
I was able to successfully run it on a lesser machine, but performance
suffered. Observer supports Ethernet (10/100/GB) and Token Ring (4/16MB),
FDDI, and Frame Relay topologies as long as your network card uses an
NDIS 3.0/3.1 or higher driver. The driver must support promiscuous mode.
Observer boasts data collection and analysis components. The data collection
process grabs information off the LAN segment to which it’s connected,
while the analysis process decodes and displays data gathered in the data
collection process. On its own, Observer is limited to sniffing the local
segment, but you can use probes to view information on remote segments.
Probes run on remote machines, and they collect data and send it back
to Observer for decoding. Observer supports more than 500 protocols, including
TCP/IP, IPX/SPX, NetBIOS/ NetBEUI, AppleTalk and SNA.
Observer works in both switched and non-switched networks (not all protocol
analyzers work in a switched environment). It handles switches in a few
different ways, through SNMP, port looping and static port redirection.
Keep in mind that, to manage the switch, your switch must support “port
spanning” and have a telnet or SNMP interface.
In addition to viewing packets as they come across the cable, Observer
does a good job of checking the health of your network hardware. It displays
traffic patterns in real time for up to eight routers at once. All data
can be viewed in several different ways, such as graphs, 3-D and pie charts.
|The Observer console is easy to use. Most tasks can
be accomplished from the toolbar. (Click image to view larger version.)
Observer can run in more than 20 different modes. Each mode performs
various functions, such as:
- Network Discovery Mode—Discovers all of the network addresses
on the segment.
- Network Trending Mode— Shows you how your network’s performing
- Packet Capture Mode—Allows you to use filters to collect required
LAN traffic data.
- Bandwidth Utilization Mode—Shows you, in real time, the total
amount of bandwidth being used.
- Internet Observer Mode—Monitors Internet traffic on your network.
Observer’s an excellent product if you don’t mind spending time getting
used to how it works. This isn’t to say Observer’s difficult to use—it’s
For those who want more than what Netmon can deliver, Observer 8.1 is
an excellent choice.
Chad Todd, MCSE, MCT, CNE, is the author of Hack Proofing Windows 2000 Server by Syngress Publishing. He is the co-owner of Training Concepts, which specializes in Windows 2000 and Cisco training.