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AOL history (.aut)

.aut file signature | application/octet-stream

AOL history (ARL) and typed URL (AUT) files

Safe

Magic Bytes

Offset 0
D4 2A

Sources: Gary Kessler

Extension

.aut

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .aut files in Python

Python
def is_aut(file_path: str) -> bool:
    """Check if file is a valid AUT by magic bytes."""
    signature = bytes([0xD4, 0x2A])
    with open(file_path, "rb") as f:
        return f.read(2) == signature

How to validate .aut files in Node.js

Node.js
function isAUT(buffer: Buffer): boolean {
  const signature = Buffer.from([0xD4, 0x2A]);
  return buffer.subarray(0, 2).equals(signature);
}

How to validate .aut files in Go

Go
func IsAUT(data []byte) bool {
    signature := []byte{0xD4, 0x2A}
    if len(data) < 2 {
        return false
    }
    return bytes.Equal(data[:2], signature)
}

API Endpoint

GET /api/v1/aut
curl https://filesignature.org/api/v1/aut

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .aut file?

A .aut file is a AOL history file. AOL history (ARL) and typed URL (AUT) files

What are the magic bytes for .aut files?

The magic bytes for AOL history files are D4 2A at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .aut file?

To validate a .aut file, read the first bytes of the file and compare them against the known magic bytes (D4 2A) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .aut files?

There is no officially registered MIME type for .aut files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .aut files?

AOL history (.aut) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.