I'm using Net::SNMP to pull Bridge table information from a number of managable switches. For the most part, everything works just fine. The problem is that some number of hardware addresses do not come through correctly (maybe 1 in a 100). My guess there is a translation issue where the hardware address is somehow being converted to a different format before it is displayed.

I have used Data::Dumper to view the returning information, and the error is there. I have used the translate() option of Net::SNMP and it only makes things worse. Also, the shell version of snmpwalk does not exhibit the problem at all! (But of course I would rather use perl modules rather than system calls.)

Again, most hardware addresses come through fine, but one example:
'000d56385734' is displayed as '^@^MV8W4'

And I can't find a relationship between the real address and the output - assuming there is one. Also, I get the same results from both the layer 2 switch the node is plugged in to, and the layer 3 core switch in the network - different manufacturers.

Following is a stripped down version of the code I am using (the final output is just a list of mac addresses that the switch knows about): 

#!/usr/bin/perl
use strict;

use Net::SNMP;

my ( $key );

my $session = Net::SNMP->session(Hostname  => '1.2.3.4',
                                 Community => 'public');

print $session->error();

my $macoid = '1.3.6.1.2.1.17.4.3.1.1';
my $macref = $session->get_table($macoid);

foreach $key (keys %{$macref}) {
   print "$macref->{$key} \n";
}

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TIA John

In reply to Net::SNMP and Mac Addresses by jds

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