App layer protocols

QuestionsCategory: QuestionsApp layer protocols
Fa asked 6 months ago

App layer protocols

  1. When sending an email using the SMTP protocol the body of the email ends with a line consisting of a single period. Is it possible to send a line with a single period in the body of the mail?
  2. Explain the difference between an iterative query and a recursive query in DNS.
  3. Is it possible to have a working webserver with an IP, that is not registered in the DNS system? Explain your answer. Do you know of somewhere this is used?
  4. When using FTP, you can use either passive or active FTP. What is the difference?