I’ve installed munin on a Ubuntu Server 12.04 yesterday. When checking the repots I’ve noticed 3 ip’s graphed, like the image below.
These IP’s are shown when I run munin-node-configure –suggest
# munin-node-configure --suggest Plugin | Used | Suggestions ------ | ---- | ----------- acpi | no | no [cannot read /proc/acpi/thermal_zone/*/temperature] amavis | no | no apache_accesses | yes | yes ... ip_ | yes | yes (18.104.22.168 22.214.171.124 126.96.36.199)
So it seems that the ip_ plugin is reporting the IP’s in question : 188.8.131.52 184.108.40.206 220.127.116.11
Looking inside of /usr/share/munin/plugins/ip_ we find a description :
=head3 IPv4 For the IP address "192.0.2.0", you will need the rules: iptables -I INPUT -d 192.0.2.1 iptables -I OUTPUT -s 192.0.2.1 These rules will insert, at the top of the iptables chains INPUT and OUTPUT one rule which will act as a packet counter. Since the rule does not include a "-j" argument, it will not explicitly allow or block anything.
Let’s examine my iptables rules :
# iptables -L -n Chain INPUT (policy ACCEPT) target prot opt source destination DROP all -- 18.104.22.168 0.0.0.0/0 DROP all -- 22.214.171.124 0.0.0.0/0 DROP all -- 126.96.36.199 0.0.0.0/0 ...
So, because i have a few IP’s manually banned in /etc/rc.d/rc.local, the munin ip_ plugin sees them at the top, and tries to count the traffic.
The solution is to add the server’s IP first in the iptables chain :
#iptables -I INPUT -d 188.8.131.52 #iptables -I OUTPUT -s 184.108.40.206
Replace 220.127.116.11 with the server’s IP. To make this permanently, add the two lines above to /etc/rc.d/rc.local
So, if you are using a firewall, you need to make sure that the top rules of the INPUT and OUTPUT chains contain the IP of the server.
The next step is to remove the existing graphs from munin. We need to delete the symlink
# rm /etc/munin/plugins/ip_18.104.22.168
Then we need to recreate the symlink with the correct IP address.
# ln -s /usr/share/munin/plugins/ip_ /etc/munin/plugins/ip_22.214.171.124
Finally, restart munin-node.
# service munin-node restart
Wait a few minutes, then check the network graphs again.