> For the complete documentation index, see [llms.txt](https://docs.ionos.com/cloud/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ionos.com/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/settings/bucket-policy.md).
# Bucket Policy
Bucket Policy is a JSON-based access policy language that allows you to create fine-grained permissions for your S3 buckets. With Bucket Policy, you can specify which users or services can access specific objects and what actions users can perform.
{% hint style="info" %}
**Note:** Granting access to a bucket for another IONOS user does not make the bucket appear in the user's S3 web console due to the S3 protocol's architecture. To access the bucket, the user must utilize other [S3 Tools](/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/s3-tools.md) as the granted access does not translate to interface visibility.
{% endhint %}
## Use cases
* Use this feature to grant access to a specific user or group to only a subset of the objects in your bucket.
* Restrict access to certain operations on your bucket, for example, list objects or remove object lock.
* Using Bucket Policy, you can grant access based on conditions, such as the IP address of the user.
* Create fine-grained access control rules to allow a user to put objects to a specific prefix in your bucket, but not to get objects from that prefix.
## Bucket Policy alternatives
Use [Bucket ACL](/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/settings/access-control-list/access-control-list-buckets.md) instead of Bucket Policy if you need to:
* Define permissions in a simple way such as `READ`, `WRITE`, or `FULL CONTROL`.
* Apply different sets of permissions to many objects.
Use [Share Objects with Pre-Signed URLs](/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/how-tos/share-objects-pre-signed-urls.md) for granting temporary access to authorized users for a specified period, after which the URL and the access to the object expires.
## Policy format
A JSON-formatted bucket policy contains one or more policy statements. Within a policy's statement blocks, IONOS S3 Object Storage support for policy statement elements and their values is as follows:
* **Id (optional):** A unique identifier for the policy. Example: `SamplePolicyID`.
* **Version (required):** Specifies the policy language version. The current version is `2012-10-17`.
* **Statement (required):** An array of individual statements, each specifying a permission.
* **Sid (optional):** Custom string identifying the statement. For example, `Statement1` or `Only allow access from specific source IPs`.
* **Effect (required):** Specifies the effect of the statement. Possible values: `Allow`, `Deny`.
* **Principal (required):** Specifies the user, account, service, or other entity to which the statement applies.
* `*` – Statement applies to all users (also known as 'anonymous access').
* `{"CanonicalUser": ""}` – Statement applies to the specified IONOS S3 Object Storage user.
* `{"CanonicalUser": ["", "",...]}` – Statement applies to the specified IONOS S3 Object Storage users.
* **Action (required):** Specifies the action(s) that are allowed or denied by the statement. See section 'Supported Action Values'. Example: `s3:GetObject` for allowing read access to objects.
* **Resource (required):** Must be one of the following:
* `arn:aws:s3:::` – For bucket actions (such as s3:ListBucket) and bucket subresource actions (such as `s3:GetBucketAcl`).
* `arn:aws:s3:::/*` or `arn:aws:s3:::/` – For object actions (such as `s3:PutObject`).
* **Condition (optional):** Specifies conditions for when the statement is in effect. See section 'Supported Condition Values'. Example: `{"aws:SourceIp": "123.123.123.0/24"}` restricts access to the specified IP range.
```bash
{
"Id": "Delegate certain actions to another user",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Delegate certain actions to another user",
"Action": [
"s3:ListBucket",
"s3:PutObject",
"s3:GetObject"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::my-bucket",
"arn:aws:s3:::my-bucket/*"
],
"Condition": {
"IpAddress": {
"aws:SourceIp": [
"123.123.123.123/32"
]
}
},
"Principal": {
"CanonicalUser": "783fa49356820b211a4283526fe24343"
}
}
]
}
```
## Web console
### Apply a Bucket Policy
You can apply Bucket Policy using the web console by following these steps:
1\. In the **DCD**, go to **Menu** > **Storage** > **IONOS S3 Object Storage**.
2\. From the **Buckets** list, choose the required S3 bucket and click the **Bucket settings**.
3\. In the **Bucket Policy**, click **Edit**, copy and paste the provided JSON policy, replacing `BUCKET_NAME` and `CANONICAL_USER_ID` with the actual values. You can retrieve your Canonical user ID from the **Key management** section. For more information, see [Retrieve User IDs](/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/how-tos/retrieve-user-ids.md).
4\. Click **Save**.
This action grants the specified user full access to your bucket.
```bash
{
"Id": "Share access to the bucket",
"Version": "2012-10-17",
"Statement": [
{
"Sid": "Share access to the bucket",
"Action": [
"s3:*"
],
"Effect": "Allow",
"Resource": [
"arn:aws:s3:::BUCKET_NAME",
"arn:aws:s3:::BUCKET_NAME/*"
],
"Principal": {
"CanonicalUser": "CANONICAL_USER_ID"
}
}
]
}
```
You have the option to restrict actions, define the scope of access, or incorporate conditions into the Bucket Policy for more tailored control.
### Delete a Bucket Policy
You can delete a Bucket Policy at any time using the **Bucket Policy** section in the **Bucket settings** and click **Delete**.
{% hint style="info" %}
**Info:** Removing a bucket policy is irreversible and it is advised to create a backup policy before deleting it.
{% endhint %}
## IONOS S3 Object Storage API
Use the [Bucket Policy API](https://api.ionos.com/docs/s3/v2/#tag/Policy/operation/PutBucketPolicy) to manage the Bucket Policy configuration.
## Command-line tool
Use the [CLI](/cloud/~/revisions/bM7yG7XCmGE9IxWqMpBu/managed-services/s3-object-storage/s3-tools/awscli/awscli-bucket-policy.md) to manage Bucket Policy.
## Related feature
### Block Public Access
If you have defined a bucket policy to grant public access, activating the **Block Public Access** feature will revoke these permissions, ensuring your data remains private. This feature is invaluable in scenarios where ensuring data privacy is paramount, or when you want to enforce a blanket no-public-access rule, irrespective of Bucket Policy settings.
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