rfc1460.txt
来自「RFC 的详细文档！」· 文本 代码 · 共 955 行 · 第 1/3 页
TXT
955 行
Arguments: a message-id (optionally) If a message-id is
given, it may NOT refer to a message marked as
deleted.
Restrictions: may only be given in the TRANSACTION state.
Discussion:
If an argument was given and the POP3 server issues a
positive response with a line containing information
for that message. This line is called a "scan listing"
for that message.
If no argument was given and the POP3 server issues a
positive response, then the response given is
multi-line. After the initial +OK, for each message
in the maildrop, the POP3 server responds with a line
Rose [Page 6]
RFC 1460 POP3 June 1993
containing information for that message. This line
is called a "scan listing" for that message.
In order to simplify parsing, all POP3 servers are
required to use a certain format for scan listings.
The first octets present must be the message-id of
the message. Following the message-id is the size of
the message in octets. This memo makes no requirement
on what follows the message size in the scan listing.
Minimal implementations should just end that line of
the response with a CRLF pair. More advanced
implementations may include other information, as
parsed from the message.
NOTE: This memo STRONGLY discourages
implementations from supplying additional
information in the scan listing. Other, optional,
facilities are discussed later on which permit
the client to parse the messages in the maildrop.
Note that messages marked as deleted are not listed.
Possible Responses:
+OK scan listing follows
-ERR no such message
Examples:
C: LIST
S: +OK 2 messages (320 octets)
S: 1 120
S: 2 200
S: .
...
C: LIST 2
S: +OK 2 200
...
C: LIST 3
S: -ERR no such message, only 2 messages in
maildrop
RETR msg
Arguments: a message-id (required) This message-id may
NOT refer to a message marked as deleted.
Restrictions: may only be given in the TRANSACTION state.
Discussion:
If the POP3 server issues a positive response, then the
response given is multi-line. After the initial +OK,
the POP3 server sends the message corresponding to the
Rose [Page 7]
RFC 1460 POP3 June 1993
given message-id, being careful to byte-stuff the
termination character (as with all multi-line
responses).
If the number associated with this message is higher
than the "highest number accessed" in the maildrop, the
POP3 server updates the "highest number accessed" to
the number associated with this message.
Possible Responses:
+OK message follows
-ERR no such message
Examples:
C: RETR 1
S: +OK 120 octets
S: <the POP3 server sends the entire message here>
S: .
DELE msg
Arguments: a message-id (required) This message-id
may NOT refer to a message marked as deleted.
Restrictions: may only be given in the TRANSACTION state.
Discussion:
The POP3 server marks the message as deleted. Any
future reference to the message-id associated with the
message in a POP3 command generates an error. The POP3
server does not actually delete the message until the
POP3 session enters the UPDATE state.
If the number associated with this message is higher
than the "highest number accessed" in the maildrop,
the POP3 server updates the "highest number accessed"
to the number associated with this message.
Possible Responses:
+OK message deleted
-ERR no such message
Examples:
C: DELE 1
S: +OK message 1 deleted
...
C: DELE 2
S: -ERR message 2 already deleted
NOOP
Arguments: none
Restrictions: may only be given in the TRANSACTION state.
Rose [Page 8]
RFC 1460 POP3 June 1993
Discussion:
The POP3 server does nothing, it merely replies with a
positive response.
Possible Responses:
+OK
Examples:
C: NOOP
S: +OK
LAST
Arguments: none
Restrictions: may only be issued in the TRANSACTION state.
Discussion:
The POP3 server issues a positive response with a line
containing the highest message number which accessed.
Zero is returned in case no message in the maildrop has
been accessed during previous transactions. A client
may thereafter infer that messages, if any, numbered
greater than the response to the LAST command are
messages not yet accessed by the client.
Possible Response:
+OK nn
Examples:
C: STAT
S: +OK 4 320
C: LAST
S: +OK 1
C: RETR 3
S: +OK 120 octets
S: <the POP3 server sends the entire message
here>
S: .
C: LAST
S: +OK 3
C: DELE 2
S: +OK message 2 deleted
C: LAST
S: +OK 3
C: RSET
S: +OK
C: LAST
S: +OK 0
Rose [Page 9]
RFC 1460 POP3 June 1993
RSET
Arguments: none
Restrictions: may only be given in the TRANSACTION
state.
Discussion:
If any messages have been marked as deleted by the POP3
server, they are unmarked. The POP3 server then
replies with a positive response. In addition, the
"highest number accessed" is also reset to zero.
Possible Responses:
+OK
Examples:
C: RSET
S: +OK maildrop has 2 messages (320 octets)
6. The UPDATE State
When the client issues the QUIT command from the TRANSACTION state,
the POP3 session enters the UPDATE state. (Note that if the client
issues the QUIT command from the AUTHORIZATION state, the POP3
session terminates but does NOT enter the UPDATE state.)
QUIT
Arguments: none
Restrictions: none
Discussion:
The POP3 server removes all messages marked as deleted
from the maildrop. It then releases the
exclusive-access lock on the maildrop and replies as
to the success of these operations. The TCP
connection is then closed.
Possible Responses:
+OK
Examples:
C: QUIT
S: +OK dewey POP3 server signing off (maildrop
empty)
...
C: QUIT
S: +OK dewey POP3 server signing off (2 messages
left)
...
Rose [Page 10]
RFC 1460 POP3 June 1993
7. Optional POP3 Commands
The POP3 commands discussed above must be supported by all minimal
implementations of POP3 servers.
The optional POP3 commands described below permit a POP3 client
greater freedom in message handling, while preserving a simple POP3
server implementation.
NOTE: This memo STRONGLY encourages implementations to
support these commands in lieu of developing augmented
drop and scan listings. In short, the philosophy of
this memo is to put intelligence in the part of the
POP3 client and not the POP3 server.
TOP msg n
Arguments: a message-id (required) and a number. This
message-id may NOT refer to a message marked as
deleted.
Restrictions: may only be given in the TRANSACTION state.
Discussion:
If the POP3 server issues a positive response, then
the response given is multi-line. After the initial
+OK, the POP3 server sends the headers of the message,
the blank line separating the headers from the body,
and then the number of lines indicated message's body,
being careful to byte-stuff the termination character
(as with all multi-line responses).
Note that if the number of lines requested by the POP3
client is greater than than the number of lines in the
body, then the POP3 server sends the entire message.
Possible Responses:
+OK top of message follows
-ERR no such message
Examples:
C: TOP 10
S: +OK
S: <the POP3 server sends the headers of the
message, a blank line, and the first 10 lines
of the body of the message>
S: .
...
C: TOP 100
S: -ERR no such message
Rose [Page 11]
RFC 1460 POP3 June 1993
APOP name digest
Arguments: a server specific user-id and a digest string
(both required).
Restrictions: may only be given in the AUTHORIZATION
state after the POP3 greeting
Discussion:
Normally, each POP3 session starts with a USER/PASS
exchange. This results in a server/user-id specific
password being sent in the clear on the network. For
intermittent use of POP3, this may not introduce a
sizable risk. However, many POP3 client
implementations connect to the POP3 server on a
regular basis -- to check for new mail. Further the
interval of session initiation may be on the order of
five minutes. Hence, the risk of password capture is
⌨️ 快捷键说明
复制代码Ctrl + C
搜索代码Ctrl + F
全屏模式F11
增大字号Ctrl + =
减小字号Ctrl + -
显示快捷键?