Last Updated on 4 weeks by Sachin G
MRTG (Multi Router Traffic Grapher) is a reliable and lightweight tool for Linux servers’ network traffic monitoring. I had to set up MRTG on both CentOS and RHEL for a legacy environment where simplicity and SNMP-based interface traffic stats were more important than dashboards or APIs.The tech article provides steps for install MRTG on Linux and setting up the Multi Router Traffic Grapher (MRTG) on various Linux distributions. It outlines the necessary steps, including installing the EPEL repository, updating package repositories, installing the Apache web server, and configuring SNMP.
Why Use MRTG for Linux Bandwidth Graphing?
MRTG is still quite useful for visual network utilization in lightweight environments. It generates HTML graphs using data collected via SNMP configuration and presents them in a format that’s easy to read—even for less experienced admins. In small and medium-sized setups where full-stack monitoring is overkill, MRTG strikes the right balance between visibility and simplicity.
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See Curated Courses →Installing MRTG on CentOS, RHEL, and Fedora
Here’s the exact method I used:
STEP 1: Install EPEL Repository
Click on the link below and install the EPEL repository according to your operating system.
Setup EPEL YUM Repositories on CentOS RHEL Fedora Linux
STEP 2: Update Package Repositories:
Make sure your system’s package repositories are up to date by running the following commands:
Here we are creating a basic installation of the Apache web server.
STEP 3: Install the Apache web server and enable the service
sudo dnf -y install httpdYou will need to start Apache if it’s not already running:
sudo systemctl enable httpd --nowSTEP 4: Install MRTG through YUM
The command below is for the mrtg and snmp installation utility and dependency.
sudo dnf install mrtg net-snmp net-snmp-utils On Fedora, the package names are the same, though you may encounter newer versions due to Fedora’s faster release cycle. This article serves as an MRTG setup tutorial for Fedora Linux as well, with only minor changes in file locations.
STEP 5: Configure SNMP
To monitor network interface and other resources like CPU, memory, we should configure snmpd “/etc/snmp/snmpd.conf”. Here’s a basic /etc/snmp/snmpd.conf Snippet I often use:
rocommunity public
syslocation ServerRoom
syscontact admin@example.comAnd check the settings below also.
(A) Comment the line with a hash on line number approx 41 like below.
# com2sec notConfigUser default public
(B) Uncomment these lines and remove NETWORK/24 and replace it with your network.
Before changes #com2sec local localhost COMMUNITY #com2sec mynetwork NETWORK/24 COMMUNITY
After Changes com2sec local localhost techtransit com2sec mynetwork 172.24.0.0/24 techtransit
(C) Uncomment the lines below. Replace techtransit with any word.
group MyRWGroup v2c local
group MyROGroup v2c mynetwork(D) Uncomment the line.
view all included .1 80(E) Uncomment these lines below if persistent. Replace techtransit with your name.
access MyROGroup "" v2c noauth 0 all none none access MyRWGroup "" v2c noauth 0 all all all
STEP 6: Start the snmpd service and enable it from autoboot.
sudo systemctl start snmpd.service
sudo systemctl enable snmpd.service
STEP 7: To test that SNMP is working:
This command helps ensure your SNMP daemon on Linux is running properly.
show status (replace the “techtransit” with your community name)
[root@server ~]# snmpwalk -v2c -c techtransit localhost systemSNMPv2-MIB::sysDescr.0 = STRING: Linux server.techtransit.org 3.10.0-229.14.1.el7.x86_64 #1 SMP Tue Sep 15 15:05:51 UTC 2015 x86_64 SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10 DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (8004) 0:01:20.04 SNMPv2-MIB::sysContact.0 = STRING: Root <root@localhost> (configure /etc/snmp/snmp.local.conf) SNMPv2-MIB::sysName.0 = STRING: server.techtransit.org SNMPv2-MIB::sysLocation.0 = STRING: Unknown (edit /etc/snmp/snmpd.conf) SNMPv2-MIB::sysORLastChange.0 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORID.1 = OID: SNMP-MPD-MIB::snmpMPDCompliance SNMPv2-MIB::sysORID.2 = OID: SNMP-USER-BASED-SM-MIB::usmMIBCompliance SNMPv2-MIB::sysORID.3 = OID: SNMP-FRAMEWORK-MIB::snmpFrameworkMIBCompliance SNMPv2-MIB::sysORID.4 = OID: SNMPv2-MIB::snmpMIB SNMPv2-MIB::sysORID.5 = OID: TCP-MIB::tcpMIB SNMPv2-MIB::sysORID.6 = OID: IP-MIB::ip SNMPv2-MIB::sysORID.7 = OID: UDP-MIB::udpMIB SNMPv2-MIB::sysORID.8 = OID: SNMP-VIEW-BASED-ACM-MIB::vacmBasicGroup SNMPv2-MIB::sysORID.9 = OID: SNMP-NOTIFICATION-MIB::snmpNotifyFullCompliance SNMPv2-MIB::sysORID.10 = OID: NOTIFICATION-LOG-MIB::notificationLogMIB SNMPv2-MIB::sysORDescr.1 = STRING: The MIB for Message Processing and Dispatching. SNMPv2-MIB::sysORDescr.2 = STRING: The management information definitions for the SNMP User-based Security Model. SNMPv2-MIB::sysORDescr.3 = STRING: The SNMP Management Architecture MIB. SNMPv2-MIB::sysORDescr.4 = STRING: The MIB module for SNMPv2 entities SNMPv2-MIB::sysORDescr.5 = STRING: The MIB module for managing TCP implementations SNMPv2-MIB::sysORDescr.6 = STRING: The MIB module for managing IP and ICMP implementations SNMPv2-MIB::sysORDescr.7 = STRING: The MIB module for managing UDP implementations SNMPv2-MIB::sysORDescr.8 = STRING: View-based Access Control Model for SNMP. SNMPv2-MIB::sysORDescr.9 = STRING: The MIB modules for managing SNMP Notification, plus filtering. SNMPv2-MIB::sysORDescr.10 = STRING: The MIB module for logging SNMP Notifications. SNMPv2-MIB::sysORUpTime.1 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.2 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.3 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.4 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.5 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.6 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.7 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.8 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.9 = Timeticks: (2) 0:00:00.02 SNMPv2-MIB::sysORUpTime.10 = Timeticks: (2) 0:00:00.02
Creating the MRTG Configuration File
MRTG includes a tool called cfgmaker to auto-generate the MRTG configuration file. Now we will create a configuration file for MRTG data storage, run the command below, and the output will be redirected to the MRTG configuration file. Replace your community name and ip of your server. You can also change WorkDir.
cfgmaker --snmp-options=:::::2 --ifref=descr --ifdesc=descr --global 'WorkDir: /var/www/html/mymrtg' techtransit@172.24.0.69 > /etc/mrtg/mrtg.cfg
If you want the graph data in bits instead of bytes, uncomment the lines below from /etc/mrtg/mrtg.cfg configuration file.
vim /etc/mrtg/mrtg.cfg
Options[_]: growright, bitsUncomment the below line, which should be on line approx 75, and save and exit from the configuration file.
Target[172.24.0.69_eth0]: \eth0:techtransit@172.24.0.69:::::2 noHC[172.24.0.69_eth0]: yes SetEnv[172.24.0.69_eth0]: MRTG_INT_IP="172.24.0.69" MRTG_INT_DESCR="eth0" MaxBytes[172.24.0.69_eth0]: 250000000 Title[172.24.0.69_eth0]: eth0 -- server.techtransit.org PageTop[172.24.0.69_eth0]: <h1>eth0 -- server.techtransit.org</h1>
indexmaker --columns=1 /etc/mrtg/mrtg.cfg > /var/www/html/mymrtg/index.html
You’ll want to run the last command at least three times to populate the RRD (Round Robin Database) and graphs.
Now, MRTG is configured in Apache configuration file.
Edit the mrtg apache configuration file.
#vim /etc/httpd/conf.d/mrtg.confEdit the file as below, change the ip with your ip .
Alias /mrtg /var/www/html/mymrtg
<Location /var/www/html/mymrtg>
Require local
Require ip 172.24.0.69
# Require host example.org
</Location>Start Apache :
#systemctl start httpd.service
To make the graphs update automatically every 5 minutes, add a cron job
*/5 * * * * /usr/bin/env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfgNow the configuration has been done, and the access URL for Graph will be as below.
Accessing MRTG Graphs
Once configured, you can view your graphs by visiting:
http://server-hostname or http://your-server-ip/mrtg/If you’re wondering where MRTG graph files are stored in Linux, they’re typically in /var/www/html/mrtg/.
In my case, this setup provided clear bandwidth data for multiple interfaces and was extremely useful for system performance monitoring during peak hours.
Monitoring Multiple Interfaces and Remote Devices
The common query: Can MRTG monitor traffic on multiple network interfaces? — Yes, MRTG supports this out of the box if SNMP exposes those interfaces. You can include them in your config using cfgmaker, or manually edit the .cfg file.
Can MRTG monitor remote servers via SNMP? — Absolutely. As long as SNMP is enabled on the remote system and accessible from your monitoring host, MRTG will work .
Frequently Asked Questions (FAQ)
MRTG is more lightweight and easier to configure than Cacti or Zabbix. It doesn’t require a database and uses static HTML output, which is great for resource-limited servers or when simplicity is key.
MRTG itself serves graphs over HTTP (usually port 80), while SNMP operates over UDP port 161. Make sure these are open in your firewall or network security groups.
Logs for MRTG are usually written to /var/log/mrtg/mrtg.log to your system’s cron logs. Use tail -f or journalctl to view real-time issues during setup.
I’m Sachin Gupta — a freelance IT support specialist and founder of techtransit.org. I’m certified in Linux, Ansible, OpenShift (Red Hat), cPanel, and ITIL, with over 15 years of hands-on experience. I create beginner-friendly Linux tutorials, help with Ansible automation, and offer IT support on platforms like Upwork, Freelancer, and PeoplePerHour. Follow Tech Transit for practical tips, hosting guides, and real-world Linux expertise!