Data packet Edit
A header is
|“||[i]dentifying information transmitted as part of the data packet or as e-mail or newsgroup routing information.||”|
Digital work Edit
Electronic mail Edit
A header is
|“||the section of an email message that contains vital information about the message, including origination date, sender, recipient(s), delivery path, subject, and format information. The header is generally left in clear text even when the body of the email message is encrypted.||”|
|“||[t]he portion of a message that contains information used to guide the message to the correct destination. Note: Examples of items that may be in a header are the addresses of the sender and receiver, precedence level, routing instructions, and synchronizing bits.||”|
File management Edit
A header is a region at the beginning of each file where bookkeeping information is kept. The file header may contain the date the file was created, the date it was last updated, and the file’s size. The header can be accessed only by the operating system or by specialized computer programs.
Network transmission Edit
- ↑ Investigations Involving the Internet and Computer Networks, at 87.
- ↑ NIST Special Publication 800-45, Glossary, at A-1.
- ↑ Cybersecurity A Primer for State Utility Regulators, App. B.