How-To MRTG bandwidth monitoring utility

[wpte]

Do you want to measure what's going in and what's going out your router? I always did, and after some searching I found a tool to do this and plot it in a graph


I found MRTG which is the predecessor of RRDtool, used by the largest internet exchange in the world: Amsterdam Internet Exchange
Now, RRDtool is nice, but it will be too advanced for what we want to do, so in this how-to we'll stick to MRTG which does the job just as well
The good thing about this monitor is that it only polls once every 5 minutes, so it uses hardly any CPU and will allow the harddrive to spin down now and then.


Before you begin
You need a proper IPKG setup (e.g. from wengi's how-to).
Also you need to activate the SNMP server in the webadmin interface:

Set it up like in this screenshot
Furthermore, you need some way to access the generated graphs, this can be done via a samba share or a webserver.


Installing
It's as easy as executing:

ipkg install mrtg

Creating config files
The IPKG package doesn't come with configuration files since they're different for every system!
Before you can generate a config file you NEED to make sure the SNMP server is up and running.
Adjust the workdir to your needs, this workdir should be accessible via samba or a webserver. Also don't forget to create the folder before you assign it.

/opt/bin/cfgmaker --global 'WorkDir: /tmp/mnt/share/mrtg' --global 'RunAsDaemon: Yes' --global 'Options[_]: bits,growright' --output /opt/etc/mrtg.cfg public@localhost

now wait a few seconds while the configuration is being made.

Making a startupscript

vi /opt/etc/init.d/S99mrtg

and paste the code:

#!/bin/sh
if [ -n "`pidof mrtg`" ]; then
killall mrtg 2>/dev/null
fi
/opt/bin/mrtg /opt/etc/mrtg.cfg

save it and make it executable:

chmod +x /opt/etc/init.d/S99mrtg

Starting and monitoring
Just execute

/opt/etc/init.d/S99mrtg

and it should start monitoring.
Now just browse to the folder you put as workdir (either via samba or webserver).
You'll see a few html pages called "localhost_x.html" (where x is a number).
Just open up one of those files and the browser should open a page about a single network interface containing daily, weekly, monthly and yearly graphs.
Usually "eth1" is the WAN port (where the internet goes in) so there you can see all the results for internet usage.

Note that the speeds are displayed in bits per second meaning you have to devide the numbers by 8 to get the bytes per second.

the end
I hope you'll have fun monitoring.


some extra: http://wl500g.info/showpost.php?p=205121&postcount=18
kolaCZek made a nice post about some other scripts to monitor cpu load, memory usage and ping
Just put the mrtg settings in the mrtg.cfg config file and the bash scripts in /opt/etc/mrtg (like described in the target information)
don't forget to chmod +x /some/file the bash scripts to make them executable

[ecori]

Hi,
Thanks for the info, looks like an interesting and fun addition to my router setup, however a couple of errors must be present (at least, according to me...):
RunAsDeamon: Yes is misspelled, and should be (obviously)

RunAsDaemon: Yes

That is the easy one.

I also get an error when running configmaker at the command "public@localhost". I guess a command is missing.

I also cannot make sense of the final part of your tutorial, where you put some code for speed correction. I can see no obvious location to put in the code; if I paste the code in the mrtg.cfg an error occurs.

I hope you understand the problems I encounter, and give a corrected code!
Thanks in advance
Ecori

[wpte]

Hi,
Thanks for the info, looks like an interesting and fun addition to my router setup, however a couple of errors must be present (at least, according to me...):
RunAsDeamon: Yes is misspelled, and should be (obviously)

RunAsDaemon: Yes

That is the easy one.

I also get an error when running configmaker at the command "public@localhost". I guess a command is missing.

I also cannot make sense of the final part of your tutorial, where you put some code for speed correction. I can see no obvious location to put in the code; if I paste the code in the mrtg.cfg an error occurs.

I hope you understand the problems I encounter, and give a corrected code!
Thanks in advance
Ecori

Yes sorry, fixed that typo!

I made the how-to a bit easier now, there is no more editing of the config file, just the command to create it.
The command should just work fine, be sure you didn't remove any quotation marks while editing the workdir.
Also you MUST enable the SNMP server (that's the public@localhost part), since this program uses it to gather data

[ecori]

Thanks,
much easier now, but still contains the typo en deamon - daemon. Indeed SNMP was activated, but the router was not rebooted.
Install worked fine now, waiting for the results. Process is running as indicated by ps axf.
Regards,
Ecori

[wpte]

Thanks,
much easier now, but still contains the typo en deamon - daemon. Indeed SNMP was activated, but the router was not rebooted.
Install worked fine now, waiting for the results. Process is running as indicated by ps axf.
Regards,
Ecori

good good
My graphs usually only show spikes, because they are a lot bigger than the usual internet usage.
But the weekly and monthly graphs look quite nice

[ecori]

Well, everything seems to be working great. Nice graphs, good overview. What I miss though is the total amount of traffic, what is the amount uploaded and downloaded in a day, week or month. Would be interested to see the total amount of traffic. Since this tool records the traffic activity during the day, can't we use it also for that purpose?
Regards,
Ecori

[wpte]

Well, everything seems to be working great. Nice graphs, good overview. What I miss though is the total amount of traffic, what is the amount uploaded and downloaded in a day, week or month. Would be interested to see the total amount of traffic. Since this tool records the traffic activity during the day, can't we use it also for that purpose?
Regards,
Ecori

Yes, that's one of the downsides I guess.
I found this very short article on the MRTG documentation: http://oss.oetiker.ch/mrtg/doc/mrtg-traffic-sum.en.html
it should make a summary for 1 month... so I guess that might contain the total amount of bandwidth used

[dadoupy]

Thanks!

Once, I gave it a try to do it myself, but didn't work.

This works like a dream!

[bebef_1987]

How can I use vlan1?

[wpte]

How can I use vlan1?

if it doesn't appear in the HTML files you need to uncomment it.
mrtg automatically filters out interfaces that do not return any speed. This is a problem of the build-in SNMP server and a bit thanks to the kernel as well. The problem is partially fixed thanks to lly: http://code.google.com/p/wl500g/issu...mmary%20Opened

BUT you can comment out an interface in the config yourself, not sure if everything will go allright that way

vi /opt/etc/mrtg.cfg

a bit after where it says "System", "Description", "Contact" and "Location" you'll see all the network interfaces listed by the automatic configuration tool.

you just need to scroll down and find your vlan
it probably says:

### The following interface is commented out because:
### * has a speed of 0 which makes no sense

Just remove all the # from where it says "Target" to the very last "</div>" belonging to that interface.
Save it and restart mrtg:

/opt/etc/init.d/S99mrtg

I hope that works

[bebef_1987]

i'v uncomented the interface last night and it worked but on my router (wl500gp-v2) the WAN interface is Vlan1 as i see it. At least this is the interface with the extranet ip. so i shoud use this interface or one of the other ones...

P.S. sry for my english it is a little rusty

[wpte]

i'v uncomented the interface last night and it worked but on my router (wl500gp-v2) the WAN interface is Vlan1 as i see it. At least this is the interface with the extranet ip. so i shoud use this interface or one of the other ones...

P.S. sry for my english it is a little rusty

yeh, vlan1 should be ok when you don't use auto dhcp or static ip for the WAN side

[bebef_1987]

and if i use static witch interface shoud i use?

[wpte]

and if i use static witch interface shoud i use?

then eth1 should be the one as far as I know
it has the WAN ip over here, so I guess that's the right one

[andrewak]

and it should start monitoring.
Now just browse to the folder you put as workdir (either via samba or webserver).
You'll see a few html pages called "localhost_x.html" (where x is a number).

Can't find .html files. In the specified directory appeared three files:

mrtg-l.png
mrtg-m.png
mrtg-r.png

and no one .html

In /opt/etc/mrtg.cfg (which was left 'as-is' after creation) have two uncommented interfaces - eth0, eth1

Processes snmpd and mrtg are running.

Any sudgessions how to check what's wrong?

May be I've not installed some additional libraryes? Can you paste here output of 'ipkg list_installed' from your router?