# Security considerations and limitations for S3 Tables
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The following list describes which security and access control features and functionality are unsupported or limited for S3 Tables.
+ Public access policies are not supported. Users can't modify bucket or table policies to allow public access.
+ Presigned URLs to access objects associated with a table are not supported.
+ Requests made over HTTP are not supported. Amazon S3 automatically responds with an HTTP redirect for any requests made via HTTP to upgrade the requests to HTTPS.
+ You must use AWS Signature Version 4 when making requests to an access point by using the REST APIs.
+ Requests made over the Internet Protocol version 6 (IPv6) are supported only for object-level actions over table storage endpoints, and not for the table- and bucket-level actions.
+ Table bucket and table access policies are limited to 20 KB in size.