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**cadbury** · 15-06-2005, 10:21

hi habbers

first, SNMP has completely nothing to do with the zabbix agent or agentd.
SNMP requests are initiated by the zabbix server, and answered by the client SNMP deamon.
But in zabbix, to retrieve SNMP values, you have to say the listening port is 161. This make impossible to use both the agent(d) and SNMP on a host. But you can make two hosts, with the same IP, one on port 161, the other on 10050 (the zabbix agent(d) port).
to see the SNMP MIBs and values, i suggest you a tool such as mbrowse, which display a MIB's tree, and can retrieve values from a host.
for example, the incoming bytes number since the interfaces are started are under the MIB .1.3.6.1.2.1.2.2.1.10. Make an snmpwalk of this MIB and you will see the values you can get. You will easily find more informations with google, or perhaps you already know it

.

for your virtual devices, if you can see it with ifconfig, you have too the total number of bytes sent and recieved by the interface.
you can see it for eth2 as well with this kind if command :
ifconfig eth2 | grep "RX bytes" | cut -d ":" -f 2 | cut -d " " -f 1
to see the number of recieved bytes. You have to store them as "delta (speed per second)" to see the bandwidth. And
ifconfig eth2 | grep "TX bytes" | cut -d ":" -f 2 | cut -d " " -f 1
for the output bandwidth.
Then you make a UserParameter with that

hope it can help you

Clement

**habbers** · 22-06-2005, 08:17

Thanks for you reply Cadbury. I really don't know anything about SNMP, apart from a vague memory about reading about it in Linux Journal a while ago. I will have to pull out the article and go through it again as it sounds like I need to know about it.

Thanks for the tips on bandwidth. After a bit of trial and error I have managed to get UserParameters working. I couldn't seem to be able to execute shell scripts as a user paramter but I can just write whatever values I want to a file and then execute cat as a user paramter to read them in. I also found the iptotal command which seems quite useful as a way to read traffic throughput.

I am using paramters
UserParameter=venetinTot,/sbin/ifconfig venet0 | grep "RX bytes" | cut -d ":" -f 2 | cut -d " " -f 1
UserParameter=venetoutTot,/sbin/ifconfig venet0 | grep "TX bytes" | cut -d ":" -f 2 | cut -d " " -f 1
UserParameter=vnetin5,cat /tmp/traffin5
UserParameter=vnetout5,cat /tmp/traffout5

The last 2 user parameters uses scripts like the following to get bandwidth:
#!/bin/bash

#Script to measure incoming traffic over 5min period
#takes current traffic on ethernet device and minus' traffic from 5 min ago
_newin=`/sbin/ifconfig venet0 | grep "RX bytes" | cut -d ":" -f 2 | cut -d " " -f 1`

#We check if the in traff was recorded 5 min ago if not we will just say traff for 5 min was 0
if [ -e /tmp/in ]
then
_oldin=`/bin/cat /tmp/in`
_intraff=`expr $_newin - $_oldin`
echo $_intraff > /tmp/traffin5
echo "$_newin" > /tmp/in
else
echo "$_newin" > /tmp/in
echo "0"
fi

I don't think I have it quite right yet as my incoming bandwidth and outgoing bandwidth appear to be practically exactly the same, but at least I am starting to realise what you can do with zabbix. It appears to be a great application.

**cadbury** · 22-06-2005, 10:28

this appear to be right, but a bit complicated

for sure you can see this in SNMP just by retrieving a value
here is how you can start with snmp :

the package to install is named net-snmp
it contains snmpd (the snmp daemon) generally it is here but not installed as a running daemon, because the package also contains snmp clients :
snmpget
snmpwalk
for the most importants
i also suggest you to install mBrowse, which is a graphic MIB browser.

a little definitions :
SNMP is the name of the network protocol
when a request come to a server, snmpd retrieve (or set, depends on the command) the value in the concerned MIB. MIB stands for Management Information Base. It is the databases where are stocked the values.

for example :
snmpwalk 192.168.0.1 -v 1 -c public .1.3.6.1.2.1.2.2.1.2
return you the list of available network interfaces :
IF-MIB::ifDescr.1 = STRING: BRI0/0
IF-MIB::ifDescr.2 = STRING: Ethernet0/0
IF-MIB::ifDescr.3 = STRING: Serial0/0
IF-MIB::ifDescr.4 = STRING: BRI0/0:1
IF-MIB::ifDescr.5 = STRING: BRI0/0:2
IF-MIB::ifDescr.6 = STRING: Serial1/0
IF-MIB::ifDescr.7 = STRING: Serial1/1
IF-MIB::ifDescr.8 = STRING: Serial1/2
IF-MIB::ifDescr.9 = STRING: Serial1/3
IF-MIB::ifDescr.14 = STRING: Dialer1
IF-MIB::ifDescr.15 = STRING: Dialer2

this gives you two informations : the name of the interface, and the number of the sub-MIB.
Here, eth0 is the number 2. If I want input bytes of eth0, I have to retrieve .1.3.6.1.2.1.2.2.1.10.2 . for serial1, it is .1.3.6.1.2.1.2.2.1.10.6 .
the output bytes are under .1.3.6.1.2.1.2.2.1.16
mBrowse can help you a lot for this. snmpwalk too.

snmpget retrieve juste the value of a leaf of the MIB tree. snmpwalk retrieve all the values that are under a branch, or the value of a leaf.

snmpd is as easy to configure as a non-configurable hub

: echo "rocommunity public" > /etc/snmp/snmpd.conf
that's all you need to begin

and yes

zabbix is great
but would be greater with a plug-in oriented architecture, a bit like nagios.

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creating user parameters for bandwidth monitoring

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