Configuration guide, Licensing, Listener ports – Fluke Computer Accessories User Manual

Page 59: Snmp settings

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User’s Guide – version 3.5

NetFlow Tracker

59

Configuration Guide

To open any of the settings pages, click “Settings” on the main page. If you have
password protection enabled you may have to login as an administrative user to see

the link. Each settings page controls a single aspect of the software; if you make any
changes you must click “Ok” on the page before they will be applied and changed.

“Cancel” will return to the main settings page without altering anything. It is
recommended that you do not use the “Back” button in your web browser as it can

cause changes to be lost.

Licensing

You can check the status of your licence or apply a new one using this page. If you
received a licence file, load it by clicking “Browse” to locate the file, then click “Load”. If

you received your licence in text form, paste it into the large box and press “Decode”.
Either way, the licence details will be updated to reflect the new licence. You must click

“Ok” to use the new licence.

Listener Ports

NetFlow Tracker listens for NetFlow packets sent to it by any number of routers. When
you set up NetFlow exporting on a router, you are asked to provide a port number on

the server to send exports to. This is normally 2055, and this is the default used by
NetFlow Tracker. However, if you are sending NetFlow exports to NetFlow Tracker

from more than one router it is recommended that you use a different port for each
one.
To do this, simply add the port numbers you wish to use to the list. You can also
choose to listen on all local IP addresses or only one if the server running NetFlow

Tracker has more than one IP address and you wish to listen for NetFlow exports on a
specific address rather than on all of them.
When you have added all the ports you wish to listen for NetFlow exports on, click “Ok”.
If you get an error message, it is probably because one or more of the ports are in use

already. They will be marked with an asterisk (*). Remove these ports and add others
until there are no errors.
Under very heavy load you may need to increase the size of the buffer used for each
listener; see

missed flows

under

Performance Counters

below for more.

SNMP Settings

Whenever NetFlow Tracker receives exports from a previously unknown device it

attempts to scan the device using SNMP to discover its name and the properties of its
interfaces. A password called a community is required to use SNMP, and in many

cases a default community of “public” is set up on a device. If your devices do not have
a read-only community of “public” set up you should add the communities they so use to

this list. NetFlow Tracker attempts each one in turn when a new device is detected, so

you should put the most frequently used communities first in the list.

You can also set the timeout and number of retries used for SNMP requests; it is

unlikely you will need to alter these.

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