Post on 21-Nov-2014
description
Protocolos de E-mail
Diogo Rodrigues LopesPaulo Vitor Bischof
Agenda
1. Introdução;2. História;3. Funcionamento;4. Protocolos Seguros;5. Considerações finais;
SMTP
• Protocolo padrão de envio de E-mail• Criado em 1982, na Universidade do Sul da
Califórnia por Jon Postel• Envia o e-mail do client para o server
SMTP SyntaxCOMMAND DESCRIPTION
HELO <domain> (Hello) Connect to the server as specified in <domain>MAIL FROM:<reverse-path>
Tell the server the sender’s identity as specified in <reverse-path> [Mail-parameters]
RCPT TO:<forward-path>
(Recipient) Tell the server the intended recipient’s identity as specified in [Rcpt-parameters] <forward-path>
DATA Convey the message body to the serverRSET (Reset) Reset the server connectionVRFY <string> (Verify) Ask the receiver to confirm that a user has been
identifiedEXPN <string> (Expand) Ask the receiver to confirm that a mailing list has
been identifiedHELP [<string>] Obtain help informationNOOP [<string>] (No operation) Indicate no operation, but signify the sender is
still connected (i.e.,“alive”)QUIT Close the server connection
POP
• Criado em 1984• Protocolo de leitura• Copia as mensagens do server para o client• Possui problemas de sincronização, pois foi
projetado para deletar as mensagens do servidor
POPCOMMAND DESCRIPTION
BASIC COMMANDS FROM RFC 918 USER <name> Set usernamePASS <password> Set passwordSTAT Check the status of the mailbox, typically retrieves
number of messagesLIST [msg] List messages in the mailbox; Optional argument for
message [msg]RETR <msg> Retrieve message <msg>DELE <msg> Delete message <msg>QUIT QuitNOOP No operationRSET Reset
POPCOMMAND DESCRIPTION
OPTIONAL COMMANDS FROM RFC 1939 TOP <msg> <n> Retrieve the top <n> lines of message <msg>UIDL [msg] Retrieve unique id for [msg]APOP <name> <digest> A more robust form of authentication than
USER/PASSEXTENSION COMMAND FROM RFC 2449 CAPA Retrieve a list of capabilities supported by the
POP3 server
IMAP
• Criado em 1988, para solucionar problemas conhecidos do protocolo POP.
• Possui mais recursos que o POP• Solucionou a sincronização de E-mail entre server e clients.
• Permite pesquisar e-mails no servidor
IMAPCOMMAND DESCRIPTION
NOOP Perform no operationSTARTTLS Establish confidentiality and integrity protectionAUTHENTICATE <type> Choose authentication method LOGIN <user> <passwd> Login with username and password LOGOUT Logout the current userSELECT <mailbox> Select the desired mailbox to accessEXAMINE <mailbox> Same as SELECT except opens mailbox for read-onlyCREATE <mailbox> Create a mailbox with the name <mailbox>DELETE <mailbox> Delete selected mailboxRENAME <mailbox> <newmailbox>
Rename mailbox
SUBSCRIBE <mailbox> Subscribe to selected mailboxUNSUBSCRIBE <mailbox> Unsubscribe from selected mailbox
IMAPCOMMAND DESCRIPTION
LIST <reference> [pattern] List contents of current reference based on an optional pattern
LSUB <reference> [pattern] List a set of mailboxes matching the patternSTATUS <mailbox> <item> Show the status of specific items in the selected
mailboxAPPEND <mailbox> [flags] <msg> Append a message to the selected mailboxCHECK Perform a checkpoint on the currently selected mailboxCLOSE Close the currently selected mailboxEXPUNGE Expunge deleted messages from the mailboxSEARCH <criteria> Search the mailbox based on certain criteriaFETCH <message> <item> Fetch the specified item from the selected messageSTORE <message> <item> <newvalue>
Update the selected item in a message
COPY <message> <mailbox> Copy a message to the provided mailboxUID <command> [args] Perform an operation on a message based on its UIDCAPABILITY Query the server for its capabilities
Protocolos Seguros
• Surgiram na década de 90• PGP• SSL• TLS
Considerações finais
• Posso usar SSL ou TLS?• PGP ainda existe?• Qual protocolo devo configurar no meu
smartphone?• Se usar SSL a NSA pode ler meu e-mail?
Referência bibliográfica
KUROSE, James F. Redes de Computadores e a Internet – 5ª Edição.
TANENBAUM, Andrew S.; Redes de Computadores - 5ª Edição. Pearson Education do Brasil, 2011.
Obrigado
Diogo Rodrigues LopesPaulo Vitor Bischof