MRTG (Multi Router Traffic Grapher) is an application that allows us to observe the traffic of a network. It generates html pages with graphs which are refreshed according to our network’s current state. Its source is written in Perl and C which means that it can be installed in every Operating System we like. We will also need SNMP daemon (Simple Network Management Protocol) which gives us information for a network. The following installation was accomplished under Linux and specifically Fedora Core 6. With some little changes it can be used and under other distros.
2. SNMP server
2.1 Installation
Initially we install the packets needed for SNMP. Yum makes this job a lot easier.
Next we make snmpd service to start automatically for the runlevels we want.
| # yum install net-snmp-utils net-snmp |
And we start the server.
| # chkconfig --level 345 snmpd |
We can see that it is running in port 199.
| # service snmpd start |
| # netstat -natv | grep ':199' tcp 0 0 127.0.0.1:199 0.0.0.0:* LISTEN |
2.2 Configuration
We run ‘snmpwalk’ which creates a “tree” of information for our network.
If you see an output like this one you may proceed with the MRTG installation. Else you should make some configuration first.
| # snmpwalk -v 1 -c public localhost IP-MIB::ipAdEntIfIndex |
| ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.127.0.0.1 = 1 ip.ipAddrTable.ipAddrEntry.ipAdEntIfIndex.192.168.0.3 = 2 |
We keep a backup of snmpd.conf just in case anything goes wrong
| # cp /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.original |
We open it
| # nano /etc/snmp/snmpd.conf |
And do the follow changes:
- we change this line
| com2sec notConfigUser default public |
with those
| com2sec local localhost public com2sec mynetwork 10.0.0.0/8 public |
where 10.0.0.0/8 we put what our network is
- we change those lines
| group notConfigGroup v1 notConfigUser group notConfigGroup v2c notConfigUser |
with those
| group MyRWGroup v1 local group MyRWGroup v2c local group MyRWGroup usm local group MyROGroup v1 mynetwork group MyROGroup v2c mynetwork group MyROGroup usm mynetwork |
- we change those lines
| view systemview included .1.3.6.1.2.1.1 view systemview included .1.3.6.1.2.1.25.1.1 |
| view all included .1 80 |
- we change this line
| access notConfigGroup "" any noauth exact systemview none none |
with those
| access MyROGroup "" any noauth exact all none none access MyRWGroup "" any noauth exact all all none |
- and finally we change those lines
| syslocation Unknown (edit /etc/snmp/snmpd.conf) syscontact Root (configure /etc/snmp/snmp.local.conf) |
with something like this
| syslocation Linux, Fedora Core 6 syscontact Root root@localhost |
We restart the server to take affect of the notices
| # service snmpd restart |
And we run again
| # snmpwalk -v 1 -c public localhost IP-MIB::ipAdEntIfIndex |
Now we should see something like that
| IP-MIB::ipAdEntIfIndex.10.103.0.33 = INTEGER: 2 IP-MIB::ipAdEntIfIndex.127.0.0.1 = INTEGER: 1 |
3. MRTG
3.1 Installation
We again use yum
| # yum install mrtg |
3.2 Configuration
We create the folder in which our graphs and html pages will be kept
| # mkdir /var/www/html/mrtg/ |
And we run ‘cfgmaker’ for the configuration file to be created.
| # cfgmaker --global "workdir: /var/www/mrtg" -ifref=ip --output /etc/mrtg/mrtg.cfg --global 'options[_]: growright,bits' public@localhost |
Here you should pay notice to --output /etc/mrtg/mrtg.cfg as long as to public@localhost. With this command we tell MRTG to create a configuration file with the name ‘mrtg.cfg’ for the traffic of our computer (localhost). Instead of localhost you may put the address of any computer you may monitor as long as it runs SNMP.
Next we create our default index page | # indexmaker --output=/var/www/html/mrtg/index.html /etc/mrtg/mrtg.cfg |
3.2.1 Apache configuration
Next we have to configure apache for MRTG to work correctly. MRTG creates a file ‘mrtg.cfg’ under /etc/httpd/conf.d we contains all the necessary for Apache. We change it to contain the ips we want to have access to our MRTG graphs. Here I have added all my network.
| Alias /mrtg /var/www/mrtg Order deny,allow Deny from all Allow from 127.0.0.1 10.0.0.0/8 |
We run the following command
In case you get an error like this
| # mrtg /etc/mrtg/mrtg.cfg |
| ERROR: Mrtg will most likely not work properly when the environment variable LANG is set to UTF-8. Please run mrtg in an environment where this is not the case. Try the following command to start: env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg |
| # env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg 23-02-2007 17:28:53, Rateup WARNING: /usr/bin/rateup Can't remove localhost_2.old updating log file # env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg # |
| http://127.0.0.1/mrtg |
You should see something like this
And by clicking on it something like this
There are daily, weekly, monthly and yearly graphs which aren’t shown in the screenshot. By changing the .cfg file we can alter the information displayed to what we just want.
4. Outroduction With the same way it is possible to add as many computers as we want and therefore have a general overview of our network. Enjoy! ;)
No comments:
Post a Comment