# Conntrack Input Plugin

Collects stats from Netfilter's conntrack-tools.

The conntrack-tools provide a mechanism for tracking various aspects of
network connections as they are processed by netfilter. At runtime,
conntrack exposes many of those connection statistics within /proc/sys/net.
Depending on your kernel version, these files can be found in either
/proc/sys/net/ipv4/netfilter or /proc/sys/net/netfilter and will be
prefixed with either ip or nf.  This plugin reads the files specified
in its configuration and publishes each one as a field, with the prefix
normalized to ip_.

In order to simplify configuration in a heterogeneous environment, a superset
of directory and filenames can be specified.  Any locations that don't exist
will be ignored.

For more information on conntrack-tools, see the
[Netfilter Documentation](http://conntrack-tools.netfilter.org/).

## Configuration

```toml @sample.conf
# Collects conntrack stats from the configured directories and files.
[[inputs.conntrack]]
  ## The following defaults would work with multiple versions of conntrack.
  ## Note the nf_ and ip_ filename prefixes are mutually exclusive across
  ## kernel versions, as are the directory locations.

  ## Superset of filenames to look for within the conntrack dirs.
  ## Missing files will be ignored.
  files = ["ip_conntrack_count","ip_conntrack_max",
          "nf_conntrack_count","nf_conntrack_max"]

  ## Directories to search within for the conntrack files above.
  ## Missing directories will be ignored.
  dirs = ["/proc/sys/net/ipv4/netfilter","/proc/sys/net/netfilter"]
```

## Metrics

- conntrack
  - ip_conntrack_count (int, count): the number of entries in the conntrack table
  - ip_conntrack_max (int, size): the max capacity of the conntrack table

### Tags

This input does not use tags.

## Example Output

```shell
$ ./telegraf --config telegraf.conf --input-filter conntrack --test
conntrack,host=myhost ip_conntrack_count=2,ip_conntrack_max=262144 1461620427667995735
```
