From: Stephane Bortzmeyer <bortzmeyer@cnam.cnam.fr>
Subject: A set of Perl scripts to record addresses on a LAN with SNMP
Date: 26 Jun 1993 16:21:59 +0200
Organization: CNAM

I've just finished a set of Perl scripts which enables the network admini-
strator to keep tracks of the machines which are active on the LAN. These
scripts are available on ftp.cnam.fr:pub/CNAM/MISC/record_arp.tar.Z. Here
is the README:

---------------------- beginning of README --------------------
                    
            Record addresses in a LAN from SNMP agents

This set of Perl scripts allow you to record addresses of machines
which "speak" on your LAN.

It does so by dumping ARP tables of SNMP agents. ARP tables are tables of 
mapping between a MAC (Medium Access Control, hardware) addrress, such as an 
Ethernet address and a network (high-level) address, at the present time, 
only an IP address.

To use it, you need:

- Perl, a nice programming language for system and network 
administrators. Perl is available on uunet.uu.net:gnu/perl-xxx.tar.Z, on
tut.cis.ohio-state.edu:perl/xx and on jpl-devvax.jpl.nasa.gov:pub/perlxxx.
It is described in "Programming Perl" by Wall and Schwartz (O'Reilly).

- at least one SNMP agent on a frequented machine (I mean a machine
which speaks with many others, such as a central router). This 
agent has to be in MIB-II (RFC 1213). Today, almost all network devices
(hubs, routers, bridges, etc) are sold with a built-in SNMP agent. It can
also run on a general-purpose computer too. SNMP is described in "The simple
book" by Rose (Prentice-Hall).

- a software package which allows you to direct SNMP requests from
the command line. My scripts are tailored for Tricklet, but it 
shoudln't be too hard to modify them for, say, CMU's SNMP.

To get Tricklet, a great package to do network management with SNMP, ftp to 
dutepp0.et.tudelft.nl:/pub/Tricklet. There are many other interesting network
things on this machine, all made by the Data Network Performance Analysis 
Project at Delft University of Technology. Many thanks to them.
For CMU, try lancaster.andrew.cmu.edu:pub/cmu-snmpxxx.tar. 

You have the following scripts:

- arp.pl dumps the ARP table from a distant machine. Useful to test if this
machine has a correct SNMP agent.

- record_mac_addresses.pl is the most important script: it gathers information
from your agents. Edit the line beginning with "@agents=" to write your own
agents. Choose a name for your database and edit "$DBM_file_name =" and 
"$log_file_name =" accordingly. Then, run this script from crontab every 
three or four hours.

- print_mac_addresses.pl dumps the whole database. I like the following C 
shell alias "alias macaddr 'perl /path/print_mac_addresses.pl | grep -i \!$'"
which allows me to find a machine by its name, IP address or MAC address.

- remove_mac_address.pl to suppress an entry (by its IP address).

Of course, this package is without any warranty and I don't
speak for my employer...

(But if you have bug reports, I'd like to see them.)

-------------------- end of README ---------------------

Well, it was just to show that network management was useful in practice
:-) and that fancy interfaces aren't the only way to do it (cron is good 
too).

Stephane Bortzmeyer           Conservatoire National des Arts et Metiers	
bortzmeyer@cnam.cnam.fr       Laboratoire d'Informatique
                              292, rue Saint-Martin			
tel: +33 (1) 40 27 27 31      75141 Paris Cedex 03
fax: +33 (1) 40 27 27 72      France	

"C'est la nuit qu'il est beau de croire a la lumiere." E. Rostand

					
	


