NEED URGENT HELP WITH SNMP

NAVIN PARWAL · ‎05-19-2005

Folks,

I have a cisco 3550 EMI switch sending snmp traps to a snmp monitoring device. I have been told to use MRTG as well to monitor port usage of the ports. MRTG is running on a different server. Is it possible for me to configure SNMP on the router in a way that it sends traps to 2 devices. Also, how would MRTG know what trap to look for??

Thanks

nhabib · ‎05-19-2005

not sure about MRTG config, but the 3550 does allow more than one trap recipient

the command starts with (you can have more than one):

snmp-server host

paddyxdoyle · ‎05-19-2005

Hi,

MRTG is not a trap receiver as such. It works by polling a device for SNMP values, by default it pulls the ifInOctets/ifOutOctets counters for all discovered interfaces on a device.

You can however configure it to monitor any SNMP value on a device if you know the OID.

This is achieved by editing the config files created by MRTG, for example the following config file monitors CPU usage on a router and runs a script that sends an email should the utilisation reach 90%

# CPU load % (5 minute average “show processes cpu”)

Target[RouterA_CPU]: 1.3.6.1.4.1.9.2.1.58.0&1.3.6.1.4.1.9.2.1.58.0:@RouterA

ShortLegend[RouterA_CPU]: %

MaxBytes[RouterA_CPU_CPU]: 100

Options[RouterA_CPU]: gauge,growright,nobanner,noborder,transparent

Unscaled[RouterA_CPU]: dwmy

WithPeak[RouterA_CPU]: wmy

ThreshMaxO[RouterA_CPU]: 90

ThreshProgO[RouterA_CPU]: /usr/bin/CUSTOM/MRTG_CPU_Alert.sh

Title[RouterA_CPU]: CPU Utilisation (%)

YLegend[RouterA_CPU]: CPU Utilisation

Legend1[RouterA_CPU]: CPU Utilisation in % (Load)

Legend2[RouterA_CPU]: CPU Utilisation in % (Load)

Legend3[RouterA_CPU]:

Legend4[RouterA_CPU]:

LegendI[RouterA_CPU]:

LegendO[RouterA_CPU]:

So to answer your questions to only need to have SNMP configured on your devices with read community strings for MRTG to work.

HTH

Paddy

NAVIN PARWAL · ‎05-19-2005

Paddy,

Thanks a lot for your response. I would highly appreciate if you could help me. Here is the exiting configuration of the router, it is already configured to send SNMP traps to some SNMP monitoring device. My job is to use MRTG to monitor port usage and at the same time do not disrupt the snmp trap process the router is already running so that it can send the specified traps to the snmp monitoring device and also send me MRTG stats.

snmp-server engineID local xxxx

snmp-server community nortel RO

snmp-server community drats RW

snmp-server community public RO

snmp-server trap-source Loopback0

snmp-server chassis-id SAL0731HQRV

snmp-server enable traps snmp

snmp-server enable traps casa

snmp-server enable traps channel

snmp-server enable traps isdn call-information

snmp-server enable traps isdn layer2

snmp-server enable traps hsrp

snmp-server enable traps config

snmp-server enable traps entity

snmp-server enable traps envmon

snmp-server enable traps bgp

snmp-server enable traps rsvp

snmp-server enable traps frame-relay

snmp-server enable traps syslog

snmp-server enable traps rtr

snmp-server enable traps dlsw

snmp-server host 192.x.52.101 nortel

*snmp-server host 10.122.100.105 public*

Can i add this line for MRTG??? I hope this will not effect 192.x.52.101 from getting all the traps????

Thanks

swilson · ‎05-19-2005

Hi,

Yeah you can very well add that line, infact in my own setup, we were initially having to SNMP Managers, (we were migrating from one SNMP Mgr to the other one).

Also, the MRTG must be used as an SNMP-Server Host, otherwise the Router / Switch will ignore all the polling done by the MRTG Server.

Hope that this solves your problem.

Kind Regards,

Wilson Samuel

paddyxdoyle · ‎05-19-2005

Hi,

You don't need to add anything to your router as MRTG does not collect traps, it only requests information using SNMP gets so your current config is correct, just make sure you add your community string to your MRTG config.

"snmp-server host 10.122.100.105 public" means send traps to 10.122.100.105 using a communtity string of public. So unless your MRTG server has Openview or CiscoWorks or similar install, you do not need to configure this.

Have a look here for a fuller description

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_command_reference_chapter09186a00800d983e.html#wp1056809

Thanks

Paddy

NAVIN PARWAL · ‎05-19-2005

thanks you very much for answering my question. So all i need is community value on the router that should match on MRTG.

I am having the stange problem now, where I specify the community string in MRTG, it accepts and runs the script but hangs at the following stage:

--base: walking if speed

any ideas why the commander program hangs when it reaches this stage, i am using the commerical version of MRTG.

Thanks

paddyxdoyle · ‎05-19-2005

I haven't seen this before.

Might be worth doing a debug on your device ("debug snmp packets") to see what's happening when it fails, does your application successfully walk anything?

Also, do you need to load all the MIBs into your application as if the application is using names and not OIDs to walk your device it might not know what ifspeed refers to.

Thanks

Paddy