I have a Cisco 1700 series router configured for T1 use. I was told to setup active monitoring to log uptime/flapping/etc. What options are out there for free? Cacti looks like a nightmare to setup I cant find a download of a VMWare image or I would go that route. The downloads I found expired. Any suggestions greatly appreciated.

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  • 1
    What about cacti looks like a nightmare? It's not that hard to setup (no more so than any other SNMP/MRTG based tool anyway) – Zypher Aug 12 '11 at 3:14
  • If you only care about uptime and not bandwidth try smokeping – Zoredache Aug 12 '11 at 6:51
  • Cacti is not that hard to configure, like any other tool there will be a learning curve. Google for some tutorials and take the time. I used to be in the same situation!. – Luis Ventura Aug 12 '11 at 8:21
  • If all you want is uptime nagios'll work. But the graphs of everything else that cacti gets you are pretty awesome. – Michael Lowman Aug 12 '11 at 14:49


On the cisco, add the snmp service and set the community string:

conf t snmp-server community [community string] ro

Then check what interface to monitor:

MYCISCO#show snmp mib ifmib ifindex
  FastEthernet0/0: Ifindex = 1
  Null0: Ifindex = 3
  Multilink1: Ifindex = 8

You will need the number next to the interface, in this config, Multilink1 is a bonded T1 interface, so we will remember 8 for later on.

Exit conf t and save:

wr mem

These are the OID's you'll set in PRTG, STG or any other snmp monitoring app:

Notice the 8 at the end, that is the number that indicates the interface that we identified above.


I've had a great time with PRTG and its ease of use.

  • Good, but not free – Phil Eddies Aug 15 '11 at 8:36

zenoss core. they have a virtual appliance as option as well.

  • 2
    tried it, terribly bloated. Anything else? – Jodh Emde Aug 12 '11 at 1:47
  • +1 for bloated. – Antoine Benkemoun Aug 12 '11 at 11:40
  • bloated how? I've monitored 400 devices and 75,000 datapoints with just the base VM – SpacemanSpiff Aug 12 '11 at 14:48
  • Currently using Zenoss Core and I like it, not as good as some proprietary software but very good for free. Lots of addons for monitoring servers, ups's vmware etc. – Phil Eddies Aug 15 '11 at 8:38

Define 'etc'. You can go with something simple like http://oss.oetiker.ch/mrtg/ (MRTG) or something much more full featured. What are your requirements, exactly? Bandwidth measurement? Uptime? What system are you going to use this on? (windows/unix)? Do you want alerts sent when something happens?


If you think Cacti looks complex most other "real" monitoring systems are even more complex to setup. If you have a Linux machine available you could always use syslog-ng and use a syslog to mail script to trigger e-mail alerts based on certain syslogged strings (such as %LINKPROTO etc). It's very simple but would not be as reliable and scalable as implementing nagios, zenoss, opennms or a similar system.

On the Cisco router enable remote syslogging:

logging (the ip of the Linux box running syslog)

You also need to define what you want to send to the syslog server with the snmp-trap directives (yes, snmp-traps also control syslogging).

syslog-ng.conf example:

source s_remote {
destination d_mail {
destination d_varlog {
    file("/var/log/$HOST" owner(root) group(logging) perm(0640)
filter f_cisco { 
    level(debug..emerg) and
    and not match("stuff to ignore|dog|cat");
log {

And the script to trigger emails:

#!/bin/bash -x
while read line; do
    var=$(echo $line | cut -d' ' -f4)
    echo $line | /bin/mailx -s "log notification $var" alerts@acmecorp.com

An alternative and possibly nicer way to do the same thing is to send snmp traps from the Linux box and translate the traps to emails in a similar way.


I've setup Graphite and fallen in love with it. Granted, it's best if you write your own scripts to poll for data, but sending data to it is pretty easy if you follow their sample python script.

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