97 lines
3.5 KiB
Markdown
97 lines
3.5 KiB
Markdown
# Iptables Plugin
|
|
|
|
The iptables plugin gathers packets and bytes counters for rules within a set of table and chain from the Linux's iptables firewall.
|
|
|
|
Rules are identified through associated comment. **Rules without comment are ignored**.
|
|
Indeed we need a unique ID for the rule and the rule number is not a constant: it may vary when rules are inserted/deleted at start-up or by automatic tools (interactive firewalls, fail2ban, ...).
|
|
Also when the rule set is becoming big (hundreds of lines) most people are interested in monitoring only a small part of the rule set.
|
|
|
|
Before using this plugin **you must ensure that the rules you want to monitor are named with a unique comment**. Comments are added using the `-m comment --comment "my comment"` iptables options.
|
|
|
|
The iptables command requires CAP_NET_ADMIN and CAP_NET_RAW capabilities. You have several options to grant telegraf to run iptables:
|
|
|
|
* Run telegraf as root. This is strongly discouraged.
|
|
* Configure systemd to run telegraf with CAP_NET_ADMIN and CAP_NET_RAW. This is the simplest and recommended option.
|
|
* Configure sudo to grant telegraf to run iptables. This is the most restrictive option, but require sudo setup.
|
|
|
|
### Using systemd capabilities
|
|
|
|
You may run `systemctl edit telegraf.service` and add the following:
|
|
|
|
```
|
|
[Service]
|
|
CapabilityBoundingSet=CAP_NET_RAW CAP_NET_ADMIN
|
|
AmbientCapabilities=CAP_NET_RAW CAP_NET_ADMIN
|
|
```
|
|
|
|
Since telegraf will fork a process to run iptables, `AmbientCapabilities` is required to transmit the capabilities bounding set to the forked process.
|
|
|
|
### Using sudo
|
|
|
|
You will need the following in your telegraf config:
|
|
```toml
|
|
[[inputs.iptables]]
|
|
use_sudo = true
|
|
```
|
|
|
|
You will also need to update your sudoers file:
|
|
|
|
```bash
|
|
$ visudo
|
|
# Add the following line:
|
|
Cmnd_Alias IPTABLESSHOW = /usr/bin/iptables -nvL *
|
|
telegraf ALL=(root) NOPASSWD: IPTABLESSHOW
|
|
Defaults!IPTABLESSHOW !logfile, !syslog, !pam_session
|
|
```
|
|
|
|
### Using IPtables lock feature
|
|
|
|
Defining multiple instances of this plugin in telegraf.conf can lead to concurrent IPtables access resulting in "ERROR in input [inputs.iptables]: exit status 4" messages in telegraf.log and missing metrics. Setting 'use_lock = true' in the plugin configuration will run IPtables with the '-w' switch, allowing a lock usage to prevent this error.
|
|
|
|
### Configuration:
|
|
|
|
```toml
|
|
# use sudo to run iptables
|
|
use_sudo = false
|
|
# run iptables with the lock option
|
|
use_lock = false
|
|
# Define an alternate executable, such as "ip6tables". Default is "iptables".
|
|
# binary = "ip6tables"
|
|
# defines the table to monitor:
|
|
table = "filter"
|
|
# defines the chains to monitor:
|
|
chains = [ "INPUT" ]
|
|
```
|
|
|
|
### Measurements & Fields:
|
|
|
|
|
|
- iptables
|
|
- pkts (integer, count)
|
|
- bytes (integer, bytes)
|
|
|
|
### Tags:
|
|
|
|
- All measurements have the following tags:
|
|
- table
|
|
- chain
|
|
- ruleid
|
|
|
|
The `ruleid` is the comment associated to the rule.
|
|
|
|
### Example Output:
|
|
|
|
```
|
|
$ iptables -nvL INPUT
|
|
Chain INPUT (policy DROP 0 packets, 0 bytes)
|
|
pkts bytes target prot opt in out source destination
|
|
100 1024 ACCEPT tcp -- * * 192.168.0.0/24 0.0.0.0/0 tcp dpt:22 /* ssh */
|
|
42 2048 ACCEPT tcp -- * * 192.168.0.0/24 0.0.0.0/0 tcp dpt:80 /* httpd */
|
|
```
|
|
|
|
```
|
|
$ ./telegraf --config telegraf.conf --input-filter iptables --test
|
|
iptables,table=filter,chain=INPUT,ruleid=ssh pkts=100i,bytes=1024i 1453831884664956455
|
|
iptables,table=filter,chain=INPUT,ruleid=httpd pkts=42i,bytes=2048i 1453831884664956455
|
|
```
|