---
title: Default allow behavior
---

import Tabs from "@theme/Tabs";
import TabItem from "@theme/TabItem";

# Default allow behavior

Anubis is designed to be as unintrusive as possible to your existing infrastructure.

By default, it allows all traffic unless a request matches a rule that explicitly denies or challenges it.

Only requests matching a DENY or CHALLENGE rule are blocked or challenged. All other requests are allowed. This is called "the implicit rule".

## Example: Minimal policy

If your policy only blocks a specific bot, all other requests will be allowed:

<Tabs>
<TabItem value="json" label="JSON" default>

```json
{
  "bots": [
    {
      "name": "block-amazonbot",
      "user_agent_regex": "Amazonbot",
      "action": "DENY"
    }
  ]
}
```

</TabItem>
<TabItem value="yaml" label="YAML">

```yaml
- name: block-amazonbot
  user_agent_regex: Amazonbot
  action: DENY
```

</TabItem>
</Tabs>

## How to deny by default

If you want to deny all traffic except what you explicitly allow, add a catch-all deny rule at the end of your policy list. Make sure to add ALLOW rules for any traffic you want to permit before this rule.

<Tabs>
<TabItem value="json" label="JSON" default>

```json
{
  "bots": [
    {
      "name": "allow-goodbot",
      "user_agent_regex": "GoodBot",
      "action": "ALLOW"
    },
    {
      "name": "catch-all-deny",
      "path_regex": ".*",
      "action": "DENY"
    }
  ]
}
```

</TabItem>
<TabItem value="yaml" label="YAML">

```yaml
- name: allow-goodbot
  user_agent_regex: GoodBot
  action: ALLOW
- name: catch-all-deny
  path_regex: .*
  action: DENY
```

</TabItem>
</Tabs>

## Final remarks

- Rules are evaluated in order; the first match wins.
- The implicit allow rule is always last and cannot be removed.
- Use your logs to monitor what traffic is being allowed by default.

See [Policy Definitions](./policies) for more details on writing rules.
