asked on

Using SNMP to authenticate to Cisco switch and run a script to make configuration changes

What i am trying to do it use a form of SNMP to just authenticate and connect into a cisco switch.

I run a script from my linux box and log in right now with SSH (username and password)
to make any configuration changes as of now.

I would like to connect using the RW community string and make any configuration changes that way.
I do know you can copy the configuration and make your changes and copy it back to the switch. but having 500+ switches and all different models, I just like to make this as simple as possible if I can.

Below is a copy of my sample code i am working on.
any help would be greatly appreciated

#!/usr/bin/perl

use Expect;
use Net::Ping;

# Insert commands desired here.
@commands =
(
'my edits would go here to write to the configuration', <-- example edits here
'end', <-- example edits here
'wr', <-- example edits here
' ', <-- example edits here
);

$subnet ="192.168",

##### ONLY EDIT THE THIRD OCTET HERE - DELETE, ADD OR CHANGE ******
my @thirdoct = (1, 2, 6, 7, 8, 9);

while(scalar(@thirdoct) > 0)
{
my $x = shift(@thirdoct);

@addresses = ("$x",);

###### PINGS IP ADDRESS AND WILL ONLY SSH INTO LIVE HOSTS ######
my $p = Net::Ping->new("icmp");

for my $o (1 .. 254)
{
    $pi="$subnet.$x.". $o;
        if ($p->ping($pi)) {
    print "$pi is alive.\n";

$SNMPGET_CMD = "snmpset -c <community> -v 1 $pi .1.3.6.1.4.1.9.9.25.1.1.1.2.4"; <-- example

foreach (@addresses)
        {
                $hostname = shift;
                $sshcommand = shift;
                $hostname = "$pi";
                $sshcommand = $SNMPGET_CMD;
                print("$sshcommand\n");
                switchupdate();

        }


sub switchupdate {

        my $switch = Expect->spawn($sshcommand) or die "Cannot spawn $sshcommand: $!\n";


);

        $switch->expect(30,
                [ qr/#/i,
                sub {
                        my $cmd = shift;
                        foreach (@commands)
                                {
                                        $cmd->send("$_\n");
                                }
                }],
        );


        $switch->soft_close();
}

        } else {
###### IF IP ADDRESS IS NOT PINGABLE IT TELL YOU AND MOVES ON TO THE NEXT ADDRESS ######
    print "$pi is not reachable.\n";
        }
}
}

Open in new window

arnold

You can not run scripts using snap, you could depending on what you need use a read write community to update the device using snmp set packet.

ASKER CERTIFIED SOLUTION

Rich Rumble

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

SOLUTION

giltjr

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

icewiper

ASKER

I agree with you guys on the rational behind SNMP.
I was looking to make a script become less of a hassle when writing changes to our switches.
In short, i should look into more alternative solutions.

I have been working with Expect, but would like to look into another process for running my scripts.

again, thanks for your ideas

giltjr

Using RANCID may make your life easier. I setup scripts to run the RANCID scripts, Example:

Scritpt #1 (I call it loop-update.sh) contains:

while read router
do
/usr/sbin/clogin -u $1 -v $2 -e $@ -x $3 $router \\>\\> Z-$router.log
done < routerlist

File routerlist contains the IP addresses of each device I want to perform the function on.
You execute the script by issuing the command:

./loop-update.sh myuserid mypassword commands

Where commands is a file that contains the commands I want to enter. After all is said and done, you will have a file for each router in the file routerlist named Z-xxxxxx.log where xxxxxxx is the IP address.