Nama : M Robby FNim : 1331140019Kelas : MI-2B

KODE SMTP

Reply codes in numerical orderCode

Meaning

200 (nonstandard success response, see rfc876)211 System status, or system help reply214 Help message220 <domain> Service ready221 <domain> Service closing transmission channel250 Requested mail action okay, completed251 User not local; will forward to <forward-path>252 Cannot VRFY user, but will accept message and attempt delivery354 Start mail input; end with <CRLF>.<CRLF>421 <domain> Service not available, closing transmission channel450 Requested mail action not taken: mailbox unavailable451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented503 Bad sequence of commands504 Command parameter not implemented521 <domain> does not accept mail (see rfc1846)530 Access denied (???a Sendmailism)550 Requested action not taken: mailbox unavailable551 User not local; please try <forward-path>552 Requested mail action aborted: exceeded storage allocation553 Requested action not taken: mailbox name not allowed554 Transaction failed

Reply codes grouped by commandCommand Code Description

connect220 <domain> Service ready421 <domain> Service not available, closing transmission channel

HELO250 Requested mail action okay, completed500 Syntax error, command unrecognised501 Syntax error in parameters or arguments504 Command parameter not implemented521 <domain> does not accept mail [rfc1846]421 <domain> Service not available, closing transmission channel

EHLO250 Requested mail action okay, completed550 Not implemented500 Syntax error, command unrecognised501 Syntax error in parameters or arguments504 Command parameter not implemented421 <domain> Service not available, closing transmission channel

MAIL250 Requested mail action okay, completed552 Requested mail action aborted: exceeded storage allocation451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised501 Syntax error in parameters or arguments421 <domain> Service not available, closing transmission channel

RCPT250 Requested mail action okay, completed251 User not local; will forward to <forward-path>550 Requested action not taken: mailbox unavailable551 User not local; please try <forward-path>552 Requested mail action aborted: exceeded storage allocation553 Requested action not taken: mailbox name not allowed450 Requested mail action not taken: mailbox unavailable451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised501 Syntax error in parameters or arguments503 Bad sequence of commands521 <domain> does not accept mail [rfc1846]421 <domain> Service not available, closing transmission channel

DATA354 Start mail input; end with <CRLF>.<CRLF>451 Requested action aborted: local error in processing554 Transaction failed500 Syntax error, command unrecognised501 Syntax error in parameters or arguments503 Bad sequence of commands421 <domain> Service not available, closing transmission channel

RECEIVED DATA250 Requested mail action okay, completed552 Requested mail action aborted: exceeded storage allocation554 Transaction failed451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage

RSET200 (nonstandard success response, see rfc876)250 Requested mail action okay, completed500 Syntax error, command unrecognised501 Syntax error in parameters or arguments504 Command parameter not implemented421 <domain> Service not available, closing transmission channel

SEND250 Requested mail action okay, completed552 Requested mail action aborted: exceeded storage allocation451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented421 <domain> Service not available, closing transmission channel

SOML250 Requested mail action okay, completed552 Requested mail action aborted: exceeded storage allocation451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented421 <domain> Service not available, closing transmission channel

SAML250 Requested mail action okay, completed552 Requested mail action aborted: exceeded storage allocation451 Requested action aborted: local error in processing452 Requested action not taken: insufficient system storage500 Syntax error, command unrecognised

501 Syntax error in parameters or arguments502 Command not implemented421 <domain> Service not available, closing transmission channel

VRFY250 Requested mail action okay, completed251 User not local; will forward to <forward-path>252 Cannot VRFY user, but will accept message and attempt delivery550 Requested action not taken: mailbox unavailable551 User not local; please try <forward-path>553 Requested action not taken: mailbox name not allowed500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented504 Command parameter not implemented421 <domain> Service not available, closing transmission channel

EXPN250 Requested mail action okay, completed550 Requested action not taken: mailbox unavailable500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented504 Command parameter not implemented421 <domain> Service not available, closing transmission channel

HELP211 System status, or system help reply214 Help message500 Syntax error, command unrecognised501 Syntax error in parameters or arguments502 Command not implemented504 Command parameter not implemented421 <domain> Service not available, closing transmission channel

NOOP200 (nonstandard success response, see rfc876)250 Requested mail action okay, completed500 Syntax error, command unrecognised421 <domain> Service not available, closing transmission channel

QUIT221 <domain> Service closing transmission channel500 Syntax error, command unrecognised

TURN250 Requested mail action okay, completed502 Command not implemented500 Syntax error, command unrecognised503 Bad sequence of commands

Kelemahan SMTPKelemahan SMTP adalah tidak melihat kebenaran alamat pengirim e-mail. Yang dilihat hanyalah

kebeneran alamat e-mail penerima, jika alamat tujuan ada maka pesan akan dikirimkan. Hal inilah yang bisa menjadi celah untuk kejahatan penipuan melalui e-mail. Jika ada seseorang yang berniat jahat untuk mengetahui id login dan password dari user sebuah server e-mail, maka bisa dilakukan dengan mengirimkan e-mail palsu dari administrator server e-mail untuk mengirimkan id login dan passwordnya ke alamat pengirim e-mail palsu tersebut. Id login dan password inilah yang dibutuhkan untuk melakukan kejahatan di internet.

Dengan kelemahan tersebut SMTP tetap digunakan, menurut saya mungkin karena belum ada penemuan yang lebih baik dari SMTP yang sekarang digunakan. Jika sudah ditemukan yang lebih baik biasanya akan digantikan dengan yang lebih baik dalam hal ini lebih aman dari celah kejahatan. Namun sebagus apapun suatu teknologi diciptakan tetap akan ada kekurangan atau celah yang akan ditemukan juga oleh orang lain walaupun itu membutuhkan waktu yang lama. Kalau suatu produk diciptakan sudah sempurna maka tidak akan ada namanya inovasi. Begitu juga dengan SMTP yang pada saat penemuannya tentunya sudah bagus, namun kemudian ditemukan kekurangannya.