Megabyte file

How it works

Under about 20 MB, mail often works. Over 25 MB it often does not. The door flips at the attachment cap, not at the word megabyte.

An 18 MB contract attaches. A 28 MB scan of the same pages bounces. The rule should have been a link at 25 MB.

How it differs

One megabyte-scale file is not a latency problem. Thousands of them are.

A gateway that rewrites MIME changes the hash.

Hash the file you meant to send.

On the ticket

• The practical close is a log line: time, actor, byte count, result.
• Without that line the transfer is a story.
• With it, the next person can see whether this door did what the ticket claimed.
• If the path is shared, say so in the partner profile so a later change does not silently pick a different limit, key, or region.
• On a real ticket, write down the door, the byte count, and the clock.
• For megabyte file, that means naming the host or bucket, the expected size, and the time the other side must have a complete file.
• A progress bar is not that record.
• A 200 response that arrives before the complete call is not that record.
• If a retry is allowed, say how many and whether it resumes.
• If a person must approve the send, name the person.
• Partners who receive megabyte file files should match on hash or size before they import.
• A same-length corrupt file passes a size check and fails a hash.
• Keep the published hash off the only channel an attacker can edit, or treat it as a corruption check rather than a substitution check.
• When the path changes, new key, new region, new cap, update the profile the same day so the next run does not use a stale limit.