#!/usr/bin/perl -w
use strict;
use Net::Telnet::Cisco;
my @routers;

open(ROUTERS,"<list.txt");
while(<ROUTERS>) {
  chomp;
  push @routers, $_;
}
close ROUTERS;

foreach (@routers) {
  print "updating $_\n";
  my $session = Net::Telnet::Cisco->new(Host => $_, Errmode => "return",);
  $session->ignore_warnings();
  $session->login('youruser', 'yourpass');
  $session->enable("enablepass");
  $session->cmd('conf t');
  $session->cmd('logging 10.11.12.13');
  $session->cmd('wr ');
  $session->close;
}