I am looking for a commercial software program that will ascertain
when computers or other network devices are physically removed from a
network.  My environment is 1500+ network devices with 100+ routers,
switches and hubs. I suspect the feature I'm interested in may be part
of a larger network administration tool that some company offers. 
Price is not a concern at this point.

Thinking through how a program would do what I want, one way is for it
to maintain a list of MAC addresses to compare against.  Gathering the
addresses from all the devices individually is problematic and even
impossible once routers and switches are present.  Instead, the
program might need to read internal tables from the routers and
switches where such tables list the MAC addresses of their attached
devices.  (But I'm getting ahead of myself here in mapping out a
solution.  The important thing is having a program to tell me when a
device has been removed.)

In the answer, I'm looking for the names of one or more programs, and
links  that describes how the program(s) solve my need.

(For the curious, I asked a similar question earlier about the
technology involved.  As you can see, I've abandoned the approach of
doing it myself.)

---

Request for Question Clarification by hummer-ga on 01 Sep 2006 06:38 PDT

Hi kentmm,

Is this what you have in mind?  

1) InterMapper
"InterMapper shows you the health of your network at a glance. Maps
present all routers, switches, servers, LAN and WAN links, and
connections between elements.."
Maps
"Maps provide "big picture" view of your network. Network elements
appear in their physical locations and connections and traffic are
clearly depicted..."
    * Devices that are down blink red
    * Devices that are operating normally are green
    * Links between devices are shown as lines connecting those devices
    * High traffic links have yellow or orange backgrounds
    * Links with lower traffic have "ants" - dotted lines along the
link - to show traffic above a certain threshold
"Maps provide a constant record of your entire network configuration -
which is critical in the case of failure. When routers, switches,
hubs, and servers are down, it's impossible to auto-detect their
locations or status, or similar details for connected devices. Armed
with your network maps, you'll know where to go to swap elements or
make fixes.
Status Windows display data that underlie network elements and
connections depicted on a map. Any device that supports SNMP
protocols, such as routers, switches, hubs, or servers reports a
variety of identifiers (name, port, type, DNS name, addresses) and
performance indicators (utilization, transmit and receive traffic
counts, uptime, packet loss, spanning tree information) that are
critical for regular maintenance and problem diagnosis..."
Status Window for a link showing traffic stats
"You'll see the Interface Status window at the left when you click and
hold on a link of a SNMP-speaking device. It shows the detailed
transmit and receive statistics for that interface, utilization, as
well as the device's name, link type, description, status, and IP and
MAC address."
Device Status Window showing device stats
"The Device Status window shown at the right appears when you click
and hold on a device on the map. This window displays relevant
statistics for the device, including its DNS name and IP address, its
uptime, availability, packet loss statistics (if relevant) round trip
time, and a history of its recent outages."
http://www.intermapper.com/features/index.html

Please let me know what you think before I look for more,
hummer

---

Request for Question Clarification by hummer-ga on 01 Sep 2006 08:03 PDT

Kentmm, I'm on my way out the door and will be out most of the day.
I'll respond to your reply as soon as possible. hummer

---

Clarification of Question by kentmm-ga on 09 Sep 2006 19:27 PDT

Hummer:

Yes, this is what I'm looking for.  If you can supply a few more
products, go ahead and answer the question.

-- Kent

Hi Kent,

Thank you for getting back to me and for giving me the opportunity to
post my answer, I'm glad to hear InterMapper is suitable. Here are a
few more, plus a link where you can find even more possibilities if
needed.

1) InterMapper
"InterMapper shows you the health of your network at a glance. Maps
present all routers, switches, servers, LAN and WAN links, and
connections between elements.."
http://www.intermapper.com/features/index.html

2) OpManager
"When you choose OpManager as your network monitoring software, you
are buying a powerful networking tool that can auto-discover your
entire network, group your devices into intuitive maps, monitor
devices in real-time, alert instantaneously on failure and provide
comprehensive reports and graphs.
ManageEngine OpManager is a complete network monitoring software that
offers combined WAN, Server, Applications monitoring with integrated
help desk, asset management & WAN traffic analysis functionality.
OpManager automates several network monitoring tasks and removes the
complexity associated with network management."
http://manageengine.adventnet.com/products/opmanager/

OpManager Features
WAN Monitoring
Server Monitoring
Switch Monitoring
Printer Monitoring
Windows Event Log Monitoring
URL Monitoring
Services Monitoring
Application Monitoring
Windows Services Monitoring
CPU, Memory & Disk Monitoring
APC UPS Monitoring
Fault monitoring
Performance Monitoring
Downtime Scheduler
ServiceDesk Plus Integration
Networking Tools
http://manageengine.adventnet.com/products/opmanager/features-overview.html

3) Argent SNMP Monitor
"The Argent SNMP Monitor is the world's leading solution for
monitoring hubs, switches, routers, and printers. In fact, any
SNMP-compliant device can be monitored using the Argent SNMP Monitor.
If any issues are detected, email, pager or other alerts are triggered
via the Argent Console so that customers can react quickly to network
issues before end users complain.
Argent SNMP Monitor can even monitor environmental devices like motion
and smoke detectors, security systems, temperature and humidity
gauges, and water sensors. So, if the AC unit in your server room
fails, Argent SNMP Monitor triggers alerts before servers start
overheating and failing.
With Argent's unique agent-optional architecture, the Argent SNMP
Monitor is completely scalable, extremely robust, and provides a
universal solution for monitoring all SNMP devices worldwide -- the
Argent SNMP Monitor can concurrently monitor up to 100,000 SNMP
devices."
http://www.argent.com/p/snmp/snmp.html

4) MonitorMagic
"What is MonitorMagic?
Answer: MonitorMagic is a proactive monitoring and alerting tool for
Windows 2003, 2000 and NT servers, workstations and SNMP devices. What
makes MonitorMagic unique is its flexibility to quickly manage various
components of an enterprise level or single server network. "
http://www.advtoolware.com/software/server-monitor/server-monitor.asp

MonitorMagic Technology Zone
"MonitorMagic has many unique features, such as Event Log Archiving
and Server Monitoring. The best way to learn about these features is
to visit our Demo Center or by selecting each feature from the left
navigation bar."
    * Demo Center
    * Custom Monitors
    * Report Options
    * Alarm Options
    * Document Center
http://www.advtoolware.com/software/server-monitor/server-monitor-technology-zone.asp

5) Big Brother Professional Edition
"Big Brother® Professional Edition (BBPE) is a low cost, Web-based
system and network availability monitor. It provides a highly
scalable, customizable and easy to maintain system with a small
footprint for monitoring the near real-time availability of network
devices, servers (Windows, Unix, Linux) and all network delivered
services in any IT infrastructure. BBPE displays your system and
network status on a color-coded Web page that proactively notifies you
of problems immediately via e-mail, pager or text message."
    * Monitor Servers
    * Monitor Networks
    * Monitor Network Devices
    * Monitor Applications
    * Monitor Databases
    * Monitor Storage
http://bb4.com/

6) Easy Network Service Monitor
"Easy Network Service Monitor is a network management tool that
continuously monitors network devices and services availability and
performance locally or remotely. In the event of network or
application errors, Easy Network Service Monitor can alert the network
administrator by email, phone or pager BEFORE problems get seriously
out of hand. A comprehensive log file will record every event of the
monitored devices and services for your review anytime at your
convenience, or for you to make a graphic report to pass to others.
You can also configure Easy Network Service Monitor so that when
something goes wrong, a set of actions, such as executing a program,
rebooting a server or update a web page, will be triggered, which will
help you address the problem immediately."
http://www.javvin.com/easy.html

7) GFI Network Server Monitor
"Automated server and network monitoring made easy!
GFI Network Server Monitor is a network monitor that enables
administrators to scan the network for failures or irregularities
automatically. With GFI Network Server Monitor, you can identify
issues and fix unexpected conditions before your users (or managers)
report them to you!
Maximize network and server uptime
GFI Network Server Monitor maximizes network availability by
monitoring all aspects of your Windows and Linux servers, workstations
and devices (routers, etc). When a failure is detected, GFI's network
monitor can alert you by email, pager or SMS, as well as taking
corrective action by, for example, rebooting the machine, restarting
the service or running a script."
http://www.gfi.com/nsm/?adv=172&loc=4&adclickid=8552228

8) IsItUp
"Is your network up? IsItUp  is a network device monitor, email server
monitor, server monitor, port monitor and website monitor - all in one
inexpensive package. IsItUp runs under Windows 2000 and XP. Network
Administrators use IsItUp  to monitor whether network devices are 'up'
or 'down'. IsItUp  continuously monitors multiple "pingable" devices
using TCP/IP's Ping utility.
Do you need to know if those servers are working? IsItUp server
monitor makes network monitoring easy. What's more, it has a unique
features to test email servers by bouncing messages off auto-reply
accounts. Web servers and websites are tested using HTTP with content
checking built right in. All devices are monitored at specified
intervals, notifying you, by email alert, pager alert or phone, when
they go down - or come back up."
http://www.tarosoft.com/

9) Device Reachability Monitoring: DeviceMonitorEP v1.5
"DeviceMonitorEP is a Windows NT/2000 service that will query the
reachability status of network devices, and provides a graphical map
of your network deployment so you can manage a large network from a
map interface."
http://www.netlatency.com/solutions/device_reachability_monitoring.asp

10) Monitor One
"Monitor one allows you to easily build and run a monitoring station
for SNMP enabled networks that helps you manage and control every
aspect of your network. You can monitor Uptime, bandwidth,
performance, utilization and network traffic of leased lines, routers,
firewalls, servers, managed switches, printers, and other network
components with just a few basic steps."
http://www.fineconnection.com/

11) CueVision Server Monitor
"Monitor network servers, devices and websites with Cuevision Server
Monitor Software
Cuevision Server Monitor keeps you one step ahead of problems."
http://www.cuevision.com/products.html?P=MT

12) BMC Performance Manager Express
"BMC® Performance Manager Express monitors the performance and
availability of servers, applications and storage and network devices.
Monitoring is accomplished remotely (agentless) with no software
residing on the elements being monitored. BMC Performance Manager
Express also monitors the performance and availability of simple Web
transactions. Monitoring both infrastructure and transactions enables
IT to quickly determine how infrastructure problems affect the
end-user experience.
Key Features & Benefits
 * Drives down operating costs by remotely monitoring availability of
storage and network devices, systems and application infrastructure
 * Improves service levels by reporting service problems and notifying
the appropriate contact after pinpointing the problem
 * Determines whether backend infrastructure and Web sites meet SLAs
by measuring their performance and availability against defined
objectives
 * Offers centralized access to reports, event status, configuration
and administration via a Web portal
 * Available as a licensed product or a subscription-based service"
http://www.bmc.com/products/proddocview/0,2832,19052_19429_2064403_9548,00.html

13) NetMon
"Netmon Inc is a provider of comprehensive network and environmental
monitoring solutions which give you a complete perspective of your
networks, services and devices from a variety of vantage points.
Built-in email and pager alert systems in all of our products are
designed to keep you informed of situations that are important to you
as a network administrator. "
 * Network traffic and activity monitoring
 * Bandwidth monitoring
 * Service monitoring
 * Protocol activity monitoring
 * Device monitoring and device management
 * Web activity monitoring
 * SYSLOG monitoring and event log monitoring
 * Performance monitoring and reporting
 * Cisco Netflow analysis and reporting
 * Email and pager notification / alerts
 * Environmental monitoring
http://www.netmon.ca/

14) IpMonitor
"Secure network monitoring software you can rely on to proactively
Monitor, Alert and Recover your critical applications and network
infrastructure equipment."
http://www.ipmonitor.com/default.aspx

Additional Link of Interest:

Network Monitoring Tools
http://www.monitortools.com/enterprise/

Thanks again, 
hummer

Some Google search terms used: network monitors monitoring monitor devices

Wow.  Went beyond my expectations for an answer.

I think this one is what your finding.

Many network devices support the SNMP protocol as a way of monitoring them. 

http://www.ipmonitor.com

The SNMP - QA Monitor is used to retrieve and analyze data from SNMP
enabled network devices, services and applications. The SNMP - QA
Monitor retrieves a Numeric or Textual value from an SNMP agent and
then tests the value against the rules you define.

Common uses of the SNMP - QA Monitor include: 

Identifying ICMP flood attacks 
Trapping spikes in network traffic 
Identifying packet failures 
Ensuring a minimum level of network availability 
Monitoring environmental conditions in server rooms and cabinets 
Identifying hardware problems in advance of costly failures 


Types of Alerts
ipMonitor's comprehensive suite of Alerts provides various different
notification methods, integration options and recovery actions.

Contact options include:

Cellular phone using email or text message. 
Wireless device using email or net broadcast. 
SMS enabled phone, pager or wireless device. 
Text pager. 
Numeric pager. 
Simple beeper. 
ipMonitor also includes various integration Alerts to:

Send SNMP messages to other management solutions. 
Write to the Windows® Application Event Log. 
Write to Text Log files. 
Send Custom Email Alerts to internal Help Desk / Ticket solutions.