---
title: Telegraf Documentation
description: Telegraf plugin for collecting metrics from Netfilter Conntrack
url: https://docs.influxdata.com/telegraf/v1/input-plugins/conntrack/
estimated_tokens: 2043
product: Telegraf
version: v1
---

-   Telegraf v1.0.0+

# Netfilter Conntrack Input Plugin

This plugin collects metrics from [Netfilter’s conntrack tools](https://conntrack-tools.netfilter.org/). There are two collection mechanisms for this plugin:

1. Extracting information from `/proc/net/stat/nf_conntrack` files if the `collect` option is set accordingly for finding CPU specific values.
2. Using specific files and directories by specifying the `dirs` option. 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`.

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

**Introduced in:** Telegraf v1.0.0 **Tags:** system **OS support:** linux

## Global configuration options

Plugins support additional global and plugin configuration settings for tasks such as modifying metrics, tags, and fields, creating aliases, and configuring plugin ordering. See [CONFIGURATION.md](/telegraf/v1/configuration/#plugins) for more details.

## Configuration

```toml
# Collects conntrack stats from the configured directories and files.
# This plugin ONLY supports Linux
[[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.

  ## Look through /proc/net/stat/nf_conntrack for these metrics
  ## all - aggregated statistics
  ## percpu - include detailed statistics with cpu tag
  collect = ["all", "percpu"]

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

  ## 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"]
```

## Metrics

A detailed explanation of each fields can be found in [kernel documentation](https://www.kernel.org/doc/Documentation/networking/nf_conntrack-sysctl.txt)

-   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
    -   `ip_conntrack_buckets` `(int, size)`: The size of hash table.

With `collect = ["all"]`:

-   `entries`: The number of entries in the conntrack table
-   `searched`: The number of conntrack table lookups performed
-   `found`: The number of searched entries which were successful
-   `new`: The number of entries added which were not expected before
-   `invalid`: The number of packets seen which can not be tracked
-   `ignore`: The number of packets seen which are already connected to an entry
-   `delete`: The number of entries which were removed
-   `delete_list`: The number of entries which were put to dying list
-   `insert`: The number of entries inserted into the list
-   `insert_failed`: The number of insertion attempted but failed (duplicate entry)
-   `drop`: The number of packets dropped due to conntrack failure
-   `early_drop`: The number of dropped entries to make room for new ones, if `maxsize` is reached
-   `icmp_error`: Subset of invalid. Packets that can’t be tracked due to error
-   `expect_new`: Entries added after an expectation was already present
-   `expect_create`: Expectations added
-   `expect_delete`: Expectations deleted
-   `search_restart`: Conntrack table lookups restarted due to hashtable resizes

### Tags

With `collect = ["percpu"]` will include detailed statistics per CPU thread.

Without `"percpu"` the `cpu` tag will have `all` value.

## Example Output

```text
conntrack,host=myhost ip_conntrack_count=2,ip_conntrack_max=262144 1461620427667995735
```

with stats:

```text
conntrack,cpu=all,host=localhost delete=0i,delete_list=0i,drop=2i,early_drop=0i,entries=5568i,expect_create=0i,expect_delete=0i,expect_new=0i,found=7i,icmp_error=1962i,ignore=2586413402i,insert=0i,insert_failed=2i,invalid=46853i,new=0i,search_restart=453336i,searched=0i 1615233542000000000
conntrack,host=localhost ip_conntrack_count=464,ip_conntrack_max=262144 1615233542000000000
```

#### Related

-   [Configure plugins](/telegraf/v1/configure_plugins/)
-   [Netfilter Conntrack Plugin Source](https://github.com/influxdata/telegraf/tree/v1.38.4/plugins/inputs/conntrack/README.md)