JP3315369B2 - Method and apparatus for automatically cleaning a list of e-mail addresses sent and received on the Internet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning an e-mail address list and an apparatus therefor, and more particularly, to an automatic e-mail address list including a large number of e-mail addresses. And a method and an apparatus for cleaning an e-mail address list suitable for cleaning the list.

[0002]

2. Description of the Related Art The Internet, which is a worldwide computer network, constitutes a data transmission path between remote computer networks. Today, the Internet includes various administrative organizations, educational institutions such as universities, corporations, and general households. PCs in the country are also widely used. By using e-mail on the Internet, it is possible to promptly communicate between companies, individuals, etc., so to speak, that is, transcends the physical distance. Against this background, e-mail addresses owned by individuals are also collected and stored as one of the customer databases. This has the advantage that services such as membership registration for various services, provision of information to customers, order receiving activities, and various questionnaires can be performed via e-mail, thereby speeding up service provision and saving labor. It has been recognized.

[0003] In particular, the fact that electronic mails of the same content can be easily sent to a large number of destinations has been widely used as direct mails on networks. This is exactly the same as ordinary direct mail using conventional mail, based on an e-mail address list that has been created in advance by specifying the recipient, an e-mail with the same content including advertisements and advertisements as text, It is sent to everyone on the address list. Such a transmission operation can be easily realized by using a commercially available e-mail software or the like and setting so as to transmit the same e-mail to all the addresses registered in the address book in advance. . Of course, by limiting the range of destination addresses, it is also possible to send an e-mail to only some of the addresses listed.

[0004]

As mentioned above, unlike ordinary mail, direct mail using e-mail does not require printing of a destination name and can be used very easily. If the contents of the e-mail address list, which is data, become obsolete, many e-mails will be returned from the sending or receiving mail server without being able to be delivered, or the wrong e-mail address will arrive as an incorrect e-mail address Not only does the efficiency of direct mail decrease, but also inconveniences occur, such as sending e-mail to unrelated users and causing trouble.
This is the same as the conventional direct mail by mail or solicitation by telephone. That is, an operation of updating the e-mail address list in a timely manner and removing invalid e-mail addresses, that is, cleaning of the so-called e-mail address list is indispensable.

However, conventionally, this cleaning operation has
It is common for people to manually perform the operation by manually checking the destination address of the e-mail returned due to undelivery and the e-mail address listed in the list, and further labor saving is required. is the current situation.

The present invention has been made based on the above problems, and an object of the present invention is to automatically extract invalid e-mail addresses from an e-mail address list including a large number of e-mail addresses, The present invention provides a cleaning method and an apparatus therefor that removes the information and updates the list in a timely manner.

[0007]

According to the present invention, there is provided a method of automatically cleaning a list of e-mail addresses transmitted and received on the Internet using a computer connected to the Internet, and a method for the same. The device has the following requirements (1) to (4).

(1) A list of electronic mail addresses recorded in a predetermined storage medium in a predetermined data format is read. (2) Obtain a mail address from the read list of electronic mail addresses, and inquire whether the IP address of the mail server corresponding to the domain name of the obtained mail address is registered in a predetermined name server. If registered, the IP address of the mail server is obtained. (3) When the IP address of the mail server is obtained in the step (2), it is determined whether the user name included in the mail address exists in a domain managed by the mail server according to a predetermined protocol. Inquire the mail server using a compliant command. (4) If the IP address of the mail server corresponding to the domain name of the e-mail address could not be obtained in step (2), or the mail server responded to the command sent in step (3). If a predetermined response code is returned, the e-mail address is determined to be incorrect, and the e-mail address list is updated based on the determination result.

Here, when it is determined in step (2) that the domain name included in the e-mail address does not exist, all the e-mail addresses having the same domain included in the e-mail address list are erroneously detected. And the list may be updated.

In addition, the e-mail address determined to have no corresponding domain name in step (2) and the e-mail address to which a predetermined response code of the protocol is returned in step (3) are Each of them may be classified and stored.

An automatic e-mail address list cleaning apparatus according to the present invention includes means for reading a list of e-mail addresses recorded in a predetermined storage medium in a predetermined data format; Means for acquiring a mail address from the list, first inquiry means for inquiring whether the IP address of the mail server corresponding to the domain name of the acquired mail address is registered in a predetermined name server,
Means for the first inquiry by means of the IP of the mail server
When the address is obtained, a second inquiry is made to the mail server using a command conforming to a predetermined protocol to determine whether the user name included in the mail address exists in a domain managed by the mail server.
Means for updating the list of e-mail addresses by determining that the corresponding e-mail address is incorrect when the corresponding IP address cannot be obtained by the first inquiry means, and second inquiring means When a predetermined response code is returned from the mail server, the mail server determines that the corresponding mail address is incorrect, and updates the list of electronic mail addresses. The method according to the present invention can be implemented by installing a program stored in an appropriate recording medium on a computer, and the computer on which such a program is installed corresponds to an apparatus according to the present invention.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for cleaning an e-mail address list and an apparatus therefor according to the present invention will be described below with reference to the accompanying drawings.

<< Overview of Internet Mail >> FIG.
1 schematically illustrates a schematic transmission path of an electronic mail (hereinafter, referred to as Internet mail or simply mail) circulating on the Internet. The mail server 1 is connected to the Internet N, and a client 2 is connected to the mail server 1. Many networks including other client / server systems, such as another mail server 3 and a client 4 connected to the mail server 3, are connected to the Internet N, and send and receive Internet mail between each other.

The mail server 1 is a server machine operated by a system such as UNIX. Client 2 is also a UNIX system or MS-D
A computer that runs on systems such as OS, MS-Windows, and MacOS. The connection form between the mail server 1 and the client 2 is one node on the LAN when the company owns a dedicated server by the TCP / IP protocol. When an individual connects to a server of an Internet connection provider with a personal computer, a dial-up IP connection is often used.

Internet mail is basically UNIX mail transmitted and received between UNIX systems constituting a mail server. Therefore, in order to send and receive UNIX mail to and from the client 2 such as a personal computer, the mail servers 1 and 3 are responsible for sending mail from the clients 2 and 4, respectively.
MTP servers 1a and 3a, POP servers 1b and 3b for receiving mails of clients 2 and 4, and mailboxes 1c and 1c for storing mail addressed to clients 2 and 4, respectively.
3c. Domain name server (DN
S server) 1d is a domain name included in the destination address of the mail to be transmitted (eg, if the mail address is user@abc.co.jp, abc.c after the unit price sign (@))
Indicates o.jp. ) Is converted to a corresponding IP address and returned. Thus, the mail server 1
If the IP address corresponding to the domain name included in the address of the mail to be sent is registered in the DNS server, the I-mail address of the mail server that manages the destination mail address is set.
The P address can be obtained.

[0016] SMTP (Simple Mail Transfer Protocol)
l) is a communication protocol between the sending mail client and the sending SMTP server and between the sending SMTP server and the receiving SMTP server.
For Comments 821). When sending a mail from the client 2 via the Internet N, the client 2 is connected to the mail server 1 first, specifies a destination according to SMTP via a mail transfer system usually called sendmail, and sends a mail text. I do.

The sending-side SMTP server sends the mail to the destination server of the mail to be sent, that is, sendmail of the receiving-side SMTP server, and the receiving-side SMTP server stores the mail in a corresponding mailbox by a mail command. . Therefore, the reception processing routine of the SMTP server is always active. The received mail is stored in the mailbox 3c, and the client 4 can receive the mail by logging in to the POP server 3b. Client 4
The communication between the POP server 3b and the POP server 3b is POP (Post Off
ice Protocol).

<< Overall Flow of E-mail Address Cleaning >> Next, the e-mail address cleaning method according to the present embodiment will be described with reference to the flowchart of FIG. This method is realized by, for example, installing and executing mail address cleaning software created for an appropriate platform on the client 2 shown in FIG. The software for executing the method of the present invention may be created using any software language depending on the environment in which the software is used.

First, a list of e-mail addresses to be cleaned is read into a storage area such as a working memory (step 302). In general, the mail address list is preferably supplied as a standard format such as a comma-delimited format or a tab-delimited format of a plain text file. However, even if it is an address book file such as a mail software or a WWW browser, it is preferable. If the description format can be known in advance, it is possible to read in accordance with the format. Such a mail address list file may be read from a removable medium such as a floppy disk or a magneto-optical disk, or may be read from a fixed storage medium such as a hard disk.

Next, mail addresses are sequentially acquired from the read mail address list (step 304).
The user logs in to the DNS server in the domain to which the user belongs (step 306). At this time, the TELNET protocol is used for connection with the DNS server. This is because U.S.P.
It is the most common protocol for terminal emulation based on NIX, and many types of excellent communication software can be used on various platforms, including those in the form of so-called freeware and shareware. Is attached.) The IP address of the DNS server must be set in advance as a connection destination of the TELNET connection, and the access right (account and password for connection) to the DNS server must be acquired in advance.

After logging in to the DNS server, the IP address of the mail server operated in the domain is entered for the domain name included in the mail address to be checked.
Query the address using the "nslookup" command. The “nslookup” command is a command defined in the UNIX system, and can be used to acquire domain information registered in the DNS server. Specifically, when a query is made in the form of nslookup <domain name>, the IP address of the domain (more precisely, the IP address assigned to the server specified by the domain name) Is returned. At this time, if set q = mx is specified as a parameter of the “nslookup” command, the DNS server returns the IP address of the mail server operated in the domain. Therefore, in this step 308, the IP address of the mail server to which the mail address to be checked belongs can be known. If the domain corresponding to the inquiry is not registered in the DNS server, a "Non existent domain" message is returned. In this case, the domain name is incorrectly described, or the domain itself does not exist. For reasons
It is determined that the domain name is invalid.

The result of such an inquiry to the DNS server is determined in step 310. That is, when the IP address of the mail server is returned (Step 310, Yes), the IP address is acquired (Step 312), and the IP address of the corresponding mail server is obtained.
If no address is obtained (step 310, N
In o), it is determined that the checked mail address is invalid, and the process returns to step 304 to acquire the next mail address from the list. Although not shown in FIG. 2, the e-mail addresses for which the domain names are determined to be invalid at steps 308 and 310 at this time are grouped into one group and stored in an appropriate storage medium. It may be stored. At that time, it may be written in one file. In that case, if a mail address whose domain name is determined to be an error is found, those mail addresses can be sequentially added to the file.

When the IP address of the mail server corresponding to the domain of the mail address to be checked is obtained, the user logs in to the TCP port 25 (SMTP protocol port) of the mail server by TELNET connection using the IP address. (Step 314). Next, in step 316, a mail address check process is performed with the mail server, the details of which will be described later.

As a result of the mail address check processing in step 316, a code (code "25") indicating that the checked mail address is normally accepted.
0 ”) is returned (step 318, Ye
s) It is determined that the e-mail address is correct, and the process returns to step 304 to obtain the next e-mail address to be checked from the address list. As a result of the mail address check processing in step 316, the normal completion code "2
If an error code other than "50" is returned, the process proceeds to step 320.

After step 320, step 316
The processing according to the error code returned by is performed. If the returned error code is "500" (step 320, Yes), the mail address that caused the error code is classified into an "address error group" and stored in an appropriate storage area (step 320). 322). For example, an address error group file may be generated and added to the file each time a mail address classified into the same group is detected.

If the error code is not "500", the process proceeds to step 324, where the error code is further examined. If the returned error code is "550" (step 324, Yes), the mail address that caused the error code is classified into an "address non-communication group" and stored in an appropriate storage area (step 3).
26). If the error code is not "550" (step 324, No), the mail address that caused the error code is classified into a "hold group" and stored in an appropriate storage area (step 328). Regardless of the group, the corresponding e-mail address cannot be used as it is, so it is deleted from the read address list (step 330).

When all mail addresses included in the list have been checked (step 332, Yes),
A series of cleaning processes is completed. If the address to be checked remains in the list (step 332, N
o), the process proceeds to step 304 to obtain the next mail address from the list, and the processing is continued.

<< Address Inquiry Processing to Mail Server >> Here, the procedure of the address inquiry processing to the mail server (step 316 in FIG. 2) in the cleaning method according to the present embodiment will be described in detail with reference to FIG. . For convenience of explanation, it is assumed that the user name of the client executing the cleaning is user-1, the domain name to which it belongs is hosta, and the domain name to which the mail server to be inquired belongs is hostb.

First, the client user-1 has TELNE
By TCP connection, TCP port 25 of the mail server (S
A connection request is sent to the MTP protocol port) (step 1). The mail server hostb sends a message to the hosta on the client side that the mail is ready to be received (step 2).

In response, the client user-1 sends a "HELO hosta" command giving its own domain name. In response, the mail server hostb returns a code "250 ok" that acknowledges the host name hosta (steps 3 and 4).

Next, the client user-1 sets the sender address (own address) to "MAILFrom: user-1 @ host".
The command is sent by the command "a", and the receiving side acknowledges this and returns the code "250 ok" (steps 5 and 6).

Here, the client user-1 sends the destination address of the mail to be checked to the mail server hostb in the format of, for example, "RCPT To: user-a @ hostb" by the "RCPT" command. At this time, the mail server
Hosta analyzes the received destination address and returns a predetermined response code to user-1. The response is shown as follows for each case.

<< (i) Response code "250" is returned (steps 7 and 8) >>
If the mailbox of the user identified by D exists,
The mail server understands the destination and returns the normal code "250 o
k ”. This confirmed that the email address user-a @ hostb was correct.

<< (ii) Response code "500" is returned (steps 9 and 10) >> This is a case where the mail server cannot recognize the character of the received mail address. If the email address is entered in double-byte characters (double-byte characters) instead of single-byte characters (1-byte characters) (for example, "use
When the mail address is described with full-width characters as "r-1 @ hostb". ), <User name> @ <domain name> This is a so-called input error of the mail address, for example, when the user name and the domain name of the Internet mail address to be described in the format are reversed.

<< (iii) Response code "550" is returned (steps 11 and 12) >> This code is returned when there is no user name specified in the mail address as a client of the mail server. If a non-existent user name is included in the e-mail address due to an input error (for example, the user name user-a
When "user-aa" which does not exist in b is described. ) Or a case where the user having the corresponding user name is not registered in the receiving mail server (for example, the connection provider to the Internet has been changed or the organization to which the user belonged has been left ( For example, a company retired).

As described above, when the response code corresponding to the mail address is obtained by the "RCPT" command, the client user-1 sends out the "QUIT" command, which is a connection disconnection request. On the contrary,
The receiving mail server returns an acknowledgment code "221 ok" (steps 13 and 14). The transmitting side disconnects the TCP port 25 and terminates the mail address check routine (step 15). Thereafter, the processing is performed based on the response code determination of the main routine and the processing based on the determination result (FIG. 2).
From step 318).

Note that the response code returned from the mail server of the other party is a basic code defined in RFC821, and therefore, when the cleaning method and apparatus according to the present invention are actually applied, It is preferable that the configuration is such that the determination is made flexibly in consideration of the specific response code and its meaning without being limited to the response code division exemplified in the embodiment.

As described above, according to the method and apparatus of the present invention, all mail addresses included in the mail address list are automatically checked for validity, and automatically checked based on the response code. Wrist cleaning can be performed. In particular, since the correctness of the e-mail address can be confirmed without actually sending the e-mail to the e-mail address to be checked, the user listed in the address list is not inconvenienced at all.

From the result of the check, it is also possible to estimate a change in the attribute of the user contained in the list (change of work place, school place, etc.).

[0040]

As described above in detail according to one embodiment of the present invention, the method and apparatus for automatically cleaning a list of e-mail addresses transmitted and received on the Internet according to the present invention include the following. The excellent effect can be achieved.

(1) Since the mail address list can be updated automatically by reading the mail address list, which has conventionally had to rely on manual work, a timely mail address without increasing costs such as labor costs. List maintenance is possible.

(2) At the time of checking the mail address, there is no contact such as a confirmation mail reaching the user of the address, so that no trouble is caused to the address user.

(3) According to the response code obtained at the time of the address check, it is possible to know the change in the attribute such as the place of work that has occurred to the address user.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an outline of a system of Internet mail.

FIG. 2 is a flowchart illustrating a process of a method for automatically cleaning a list of e-mail addresses transmitted and received on the Internet according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a procedure of an address inquiry process to a mail server in the flowchart of FIG. 2;

[Explanation of symbols]

 1,3 mail server 2,4 mail client 1a, 3a SMTP server 1b, 3b POP server 1c, 3c mailbox 1d domain name server N internet

Claims (5)

(57) [Claims] 1. A method of cleaning a list of e-mail addresses transmitted and received on the Internet using a computer connected to the Internet, the method comprising the following requirements (1) to (4). (1) Read a list of e-mail addresses recorded in a predetermined storage medium in a predetermined data format. (2) Obtain a mail address from the read list of electronic mail addresses, and inquire whether the IP address of the mail server corresponding to the domain name of the obtained mail address is registered in a predetermined name server. If registered, the IP address of the mail server is obtained. (3) When the IP address of the mail server is obtained in the step (2), it is determined whether the user name included in the mail address exists in a domain managed by the mail server according to a predetermined protocol. Inquire the mail server using a compliant command. (4) If the IP address of the mail server corresponding to the domain name of the e-mail address could not be obtained in step (2), or the mail server responded to the command sent in step (3). If a predetermined response code is returned, the e-mail address is determined to be incorrect, and the e-mail address list is updated based on the result of the determination. 2. When it is determined in step (2) that a domain name included in the e-mail address does not exist, it is determined that all e-mail addresses having the same domain included in the e-mail address list are incorrect. The method of claim 1, wherein the determining is performed and the list is updated. 3. An e-mail address determined to have no corresponding domain name in the step (2) and an e-mail address to which a predetermined response code of the protocol is returned in the step (3). The method according to claim 1, wherein each is classified and stored. 4. A means for reading a list of e-mail addresses recorded on a predetermined storage medium in a predetermined data format, a means for obtaining a mail address from the read list of e-mail addresses, First inquiry means for inquiring whether an IP address of a mail server corresponding to a domain name of the received mail address is registered in a predetermined name server; and
When the address is obtained, a second inquiry is made to the mail server using a command conforming to a predetermined protocol to determine whether the user name included in the mail address exists in a domain managed by the mail server.
And a means for determining that the corresponding e-mail address is incorrect and updating the list of e-mail addresses when the corresponding IP address cannot be obtained by the first inquiring means; and a second inquiring means. Means for updating a list of e-mail addresses by determining that the corresponding e-mail address is incorrect when a predetermined response code is returned from the e-mail server by the e-mail address list. Automatic cleaning equipment. 5. A computer-readable recording medium on which a program for causing a computer to execute the method for cleaning a list of e-mail addresses transmitted and received on the Internet according to claim 1 is recorded.