Wednesday, February 10, 2016

CCNAv1 Chapter 10 Notes - Mail

Chapter 10
Mail and stuff.
Application Layer
  • Classes to Sub User
  • Protocols used to exchange data
between
Part # TCP/NDP
DNS 55 Both
DHCP 67+68 UDP
TFTP 69 UDP
PTP 20+21 TCP
Telnet 27 TCP
SSH 22 TCP
SMTP 25 TCP
HTTP 80 TCP
POP 110 TCP
IMAP 143 TCP
Stops
  • Contact The DNS Server
  • Establish a connection with the IP
  • Request the Page
DNS is a hierarchical System
  • Top Level Domains (.com, .org, .edu, .uk, .gov)
    • (Has the records of second-level DNS servers)
  • Secondary DNS Servers
    • (Expel of top level)
  • Local DNS Server
    • (Copy of a secondary)

HTTP Messages:
  • Get
    • Client request for data.
  • Put
    • Upload files to server.
  • Post
    • Upload data to server.

DNS Message Parts:
  • Header
    • A
      • End Device Address
  • Question
    • NS
      • Authoritative Name Server
  • Answer
    • CNAME
      • Fully qualified domain name for alias.
        • Examples: ‘http://www.cisco.com’, ‘ftp://cisco.com’, ‘smtp.cisco.com’, ‘pop3.cisco.com’, & ‘imap.cisco.com’.
  • Authority
    • MX
      • Mail Exchange Record
  • Additional
    • AAAA
      • 128 Bit IPV6 w/ IPV6 node address

SMB/FTP
  • File Transfer
  • Client-Server
  • SMB Connection
    • Long Term Connection

  • An FTP Daemon
    • A program running on an FTP server.

  • DHCP Discover
    • Broadcast
    • Dest IP: 255.255.255.255
    • From Client that needs an IP.
    • Received By
      • All on network, only server responds.
Types:
  • .com
    • Top Level Domain
      • Has records of 2nd level domain server.
  • google.com
    • 2nd Level Domain
      • 2nd Level Domain name servers are normally authoritative servers.
      • All DNS records for the company.
  • mx.google.com
    • Subdomain
      • Mail (mx)
  • www.google.com
    • Subdomain
      • Web (www)
SMTP

  • Simple Mail Transfer Protocol
    • What happens if the server is busy?
      • Periodically sends the queued email again.
      • Continue until success.

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