Cisco 2950T 3550T SNMP and MRTG

[TechTryer]

Greetings

I am a newbbie to snmp but i was told that a graphing utility called MRTG could be used to determine the traffic through any of the cisco switches.

I would really appreciate some help or referels to websites that would be able to setup my switches to have SNMP enables and them setup MRTG to read the data display the traffic.

Much thanks and kind regards

TechTryer
<-- All we can do is do our Best -->

 

[Andyleates]

The MRTG web site gives you all you need to set the software up.

As far as your Cisco kit goes, you just need something like

snmp-server community YourCommunityString RW

in your config.

I have been using MRTG for years, so feel free to ask away.

Andy



Andy Leates MCSE CCNA MCP+I

 

[TechTryer]

Greetings Andy,

thanks for your offer, it's much appraciated.
I read on the MRTG website about how to setup a router with snmp enabled to have MRTG monitor traffic on each of it's link.

However, it uses IP address to define each link.

How would u do that on a cisco switch like Catalyst 2950 which is a layer 2 device?
How do i specify each port on the switch?

Cheers



TechTryer
<-- All we can do is do our Best -->

 

[dx1]

For your target, you can use the interface description, mac address, IP address or interface port number. You will have to check the MRTG documentation for the exact commands.

I prefer to use the interface port number because if the switch is re-booted somehow, the interface id will change.

Check the MRTG documentation. It is very helpful. If you need sample cfg file, let me know.

 

[TechTryer]

Hey Andy

If you do have a sample config, i wouldn't mind taking a look.

Just to give me an idea of how its done.

Thanks mate for all this help, its great.

Cheers


TechTryer
<-- All we can do is do our Best -->

 

[TechTryer]

I typed in this command u mentioned but the following error kept coming up from the console.

unable to sent UDP on port 161?

What is that all about?

Cheers

TechTryer
<-- All we can do is do our Best -->

 

[Andyleates]

Are you talking about the snmp command?

Are you in priv exec mode?

Can you cut and paste the error here?

Andy



Andy Leates MCSE CCNA MCP+I

 

[Nokarro]

I get some errors trying th cfgmaker with MRTG routers and some other switches works fine but Catalyst 3500XL gives me a problem , there error :

[root@CCSLABLX bin]# perl cfgmaker --global 'Workdir: /var/

http://www/html/mrtg'

--global 'Options[_]:bits,growright' --output /var/

http://www/html/mrtg/cfg/3512XL.cfg

private@10.200.201.6
--base: Get Device Info on private@10.200.201.6:
SNMP Error:
no response received
SNMPv1_Session (remote host: &quot;10.200.201.6&quot; [10.200.201.6].161)
community: &quot;private&quot;
request ID: 1354362383
PDU bufsize: 8000 bytes
timeout: 2s
retries: 5
backoff: 1)
at /usr/local/mrtg-2/bin/../lib/mrtg2/SNMP_util.pm line 621
SNMPWALK Problem for 1.3.6.1.2.1.1 on private@10.200.201.6::::::v4only
at cfgmaker line 775
WARNING: Skipping private@10.200.201.6: as no info could be retreived

--base: Writing /var/

http://www/html/mrtg/cfg/3512XL.cfg

[root@CCSLABLX bin]#

any help will be appreciated , looks like SNMP does not work on the switch ???

but :

snmp-server engineID local 0000000902000004C19D0D80
snmp-server community private RW
snmp-server community public RO

is in the switch running-config.

any help please ?

 

[Nokarro]

I figured it out it was an firewall issue *BLUSH* my firewall I blocked SNMP traffic I also saw with cfgmaker the switch replied on ports 336xx UDP.

Let me know if anyone wants the 3500XL MRTG Config.

 

[jsttry]

Nokarro, a copy of that config would be great if you could forward it to me please.

Cheers.

 

[encarnacao]

TechTryer

The message &quot;unable to sent UDP on port 161?&quot; occurs because the switch has no IP address associated with any vlan.

2950 has a management vlan (normally vlan 1). You could put some IP on it, and enable it:
--
enable
int vlan 1
ip address x.x.x.x y.y.y.y (where x=ip y=mask)
no shutdown
exit

I think this well help you.

Cheers
Encarnacao