1. Use of electronic mail

Electronic mail or e-mail - most popular form of the use of the Internet. With the aid of the electronic mail in the Internet you can send letter to millions of people throughout entire planet. There are sluices of particular messaging systems into the the internet e-mail, that  enlarges its possibilities. e-mail can support the lists of electronic addresses for the distribution; therefore men or organization can send e-mail to entire this list of the addresses of people or organizations. Sometimes the lists of distribution e-mail have elements, which are been indicators to other lists of distribution; therefore one letter can be finally delivered to thousands of people. Debatable groups on basis of e-mail are the variety of the lists of distribution. Their participants send the letter to the central server of the list of distribution, and communications send to all other members of group. This allows for people, which are located in the different temporary zones or on the different continents, news interesting discussions. With the aid of the specific routines the people can sign to the list from it without the aid of man. The server of the lists of distribution frequently allow other services, such as obtaining archives, digests of communications, or connected with the communications it is file. The groups of news USENET are the improvement of debatable post groups. Electronic mail becomes ever more important condition of conducting the daily activity. To organizations they are necessary policy for the electronic mail so that you soak to the colleagues it to correctly use, to decrease the risk of its intentional or unpremeditated incorrect use, and in order to guarantee, that the official documents, transferred with the aid of the electronic mail, correctly are processed. It is analogous with the policy of the use of a telephone, for organizations it is necessary to develop policy for the correct use of electronic mail. Politics must give general recommendations in these regions: The use of electronic mail for conducting the business activity the use of electronic mail for conducting the private affairs control of access and retention of the security of communications administration and storage of the electronic letters of basis e-mail basic post protocols in the Internet (without considering the particular protocols, sluiced or tunnelled through the Internet) are SMTP (Simple Mail Transport Protocol), POP (Post Office Protocol) and IMAP (Internet Mail Access Protocol).

2.1. SMTP

SMTP - this post protocol host-host. SMTP- server assumes letters from other systems and preserves them in the mailboxes of users. The preserved letters can be read by several methods. Users with the interactive access on the mail server can read mail with the aid of the local post applications. Users on other systems can load their letters with the aid of the program- post clients on protocols POP3 and IMAP.

UNIX-host they made most popular SMTP. widely utilized SMTP- servers they are Sendmail, Smail, MMDF and PP. the most popular SMTP- server in Unix is Sendmail, written by Bryan Ellman. It supports the creation of the turns of communications, the copying of the titles of letters, aliasy, the lists of distribution and so forth usually so that it must work as the privileged process. This means that if its protection can be will be gone around by any method, attacking will be able to damage, which far exceeds the removal of electronic letters.

 2.2. POP

 POP - this is the most popular protocol of the method of electronic mail. POP- server makes it possible to POP- client to load the letters, which were obtained by him from another mail server. Clients can load all communications or only those, which they yet did not read. It does not support the removal of communications before the load on the basis of the attributes of communication, such as the address of sender or recipient. POP version 2 support encoding of user with the aid of the password, but password is transferred to server in the open form. POP to versions 3 allows the additional method of encoding, called APOP, which hides password. Some realizations POP can use Kerberos for encoding.

 2.3 .IMAP

IMAP - this the newest, and therefore the less popular protocol of reading electronic mail. As it is said in RFC: IMAP4rev1 is supported to the operation of creation, removal, renaming of mailboxes; checking the entering of new letters; the operational removal of letters; installation and the discharge of the flags of operations; the selection of titles in size Rfc-822 and Mime- imb; search among the letters; selective reading of letters. IMAP is more convenient for reading of mail in the journey, than POP, since communications can be left on the server, which frees from the need for synchronizing the lists of the read letters on local host and on the server.

2.4.MIME

MIME - this reduction for the multipurpose expansions of parallel mail (Multipurpose Internet Mail Extensions). As it is said in RFC 2045, it identical the size of the communications of electronic mail in order to allow: Transfer it is text in the coding, different from Us- ascii, transfer in the letter to nontext information in different sizes, communications from several parts, and transfer in the title of the letter to information in the coding, different from Us- ascii. It can be used for the support of such means of safety as digital signatures and the communications. It also makes it possible to send by the mail the carried out files, infected by viruses, or letter with RPS. Like Web browsers, the program of reading mail can be configuration automatically to start application- assistants for treating the specific types MIME- communications.

3. Potential problems with electronic mail

3.1. random errors it is possible to easily commit error with the work with the electronic mail. Letter can be random sent. The simple pressure of key or the flick by mouse can send letter by the incorrect address. Post communications can be stored by years; therefore poor expression can a through much time. The archives of letters can grow to such an extent, that the system will emergency complete. The incorrectly disposed program of reading the groups of news can lead to the message of communication not into those groups. Errors in the lists of distribution can lead to the long wandering of the letters between the mail servers, the number of letters can increase to such an extent, that mail servers emergency will be completed. When the messaging system of organization is connected to the Internet, the consequences of errors can prove to be into thousands of times more badly. Here some of the methods to avoid the errors: To learn users what to make, if they completed error, and as correct to work with the electronic mail To configuration the program of electronic mail so that the standard actions of user, which use installations on silence, would be safest use the programs, which strictly realize protocols and agreements of the Internet. Each time, when online service sluices letter from the particular messaging system into the electronic mail, are heard the howls of protest because of the appearance of the large number of communications with the errors, which arose as a result of the mail servers of this service.

3.2. Personal use since letter usually is used for guaranteeing the activity of organization as telephone and fax, its use for personal purposes must be limited or forbidden (this it depends on organization). Although it is simplest to determine, that the electronic mail is used only for the solution of the problems of organization, everything are understood, which this policy is heavy to realize. If policy cannot be in concord inculcated, is unavoidable its nonobservance and then policy does not be able to be used as the basis for the punishment. It will create much wiser the policy, which establishes the clear boundaries of use e-mail for personal purposes, it is analagous to how the framework of the use of an official telephone for personal purposes are established. If you use an official telephone in order to ring in the dry cleaning, then it is highly improbable that your bell will be received as the official demand of company. But the message of electronic letter with the electronic post address, which contains the address of organization, will be similar to the message of paper letter on the firm form of company. If sender uses its login in the company for the message of electronic mail into the group of news, it can seem that the company approves the opinion, voiced by it in the letter.

 3.3. Marketing in the past, when the Internet was research network, its commercial use was forbidden. Furthermore, too few companies and people they had an access to mail; therefore it was inexpedient to use it for the commercial purposes. Now the Internet was enlarged and is permitted to use it for commercial purposes; therefore companies began to support the lists of distribution for the exchange of information with their clients. As a rule, clients must send demand in order to fall in the list of distribution. When large online services began to sluice letters into the Internet, it was unexpectedly revealed that thus it is possible to transmit the information of much larger audience. Marketing in the Internet with the aid of the message of separate post communications thus was borne. People wrote programs for the automation of the maintenance of the lists of distribution, and were formed companies for the collection and sales of the lists of electronic post addresses to the organizations, which are carried out marketing. The congress OF THE USA accepted the bill, according to which straight marketing with the aid of the electronic mail must be achieved in accordance with the same rules, to which is limited the use of a mass message of letters, so that those, who carry out such a marketing, would conduct the lists of the addresses, whose owners do not desire to obtain advertisement in the electronic letters.

4. Threats, connected with the electronic mail the basic protocols of the transfer (.SMTP, POP3.imapya) do not usually achieve reliable, which makes it possible to easily create letters with the false addresses. Any of these protocols is not used cryptography, which could guarantee the security of electronic letters. Although there are expansions of these protocols, the solution to use them must be clearly accepted as the component part of the policy of the administration of mail server. Some such expansion use the already existing means of and others make possible for client and server to agree on type of which will be used in this connection.

4.1. False addresses of sender to the address of sender in the electronic mail of the Internet cannot be entrusted, since sender can indicate false return address, either title can be modified in the course of the transfer of letter, or sender can itself be connected with SMTP- port in the machine, on behalf of which he wants to send letter, and to introduce the text of letter.

 4.2. Interception of letter titles and contents of electronic letters are transferred in the pure form. As a result the contents of communication can be read or is changed in the transmitting its on the Internet. Title can be modified in order to hide either to change sender or in order to  communication.

4.3. E-mail bombs e-mail bomb - is attack with the aid of the electronic mail. The attacked system will be overfilled by letters until it malfunctions. As this can happen, it depends on the type of mail server and that how it is configuration. Some providers of the Internet give temporary login to any for testing of connection to the Internet, and these login can be used for the beginning of similar attacks. Standard versions of the failure of mail server: Post communications start to those times, thus far the disk, where they are placed. It will not overfill. The following letters do not start. If this disk also basic system disk, then entire system can emergency be completed. Input turn will be overfilled by the communications, which must be processed and transmitted further, until the limit of size of turn not is achieved. The subsequent communications will not fall in the turn. In some messaging systems it is possible to establish the maximum number of post communications or the maximum overall size of the communications, which the user can accept for one time. The subsequent communications will be rejected or destroyed. The quota of disk for this user can be exceeded. This it will mix to accept the subsequent letters, and it can prevent it from carrying out other actions. Restoration can prove to be difficult for the user, since additional disk space for the removal of letters can be required by it. The large size of mailbox can make difficult for the system administrator obtaining system warnings and communications about the errors the message of e-mail bombs in the list of distribution it is possible to lead to the fact that its terms can style='mso-spacerun:yes'>  from the list.

4.4. Threatening letters since any person in the world can send to you letter, it can prove to be difficult to make it necessary him to end to send them to you. People can learn your address from the list of the addresses of organization, list of those, who signed themselves to the list of distribution, or the letters in Usenet. If you indicated your post address to any Web site, from it can sell your address to "post ". Some Web browsers they themselves indicate your post address, when you attend Web site; therefore you can even not understand that you gave it. Many messaging systems have the capabilities of filtering the mail, i.e., the search for the indicated words or word combinations in the title of letter or its telex-, and subsequent accommodation into the specific mailbox or the removals. But the majority of users do not know how to use a mechanism of filtration. Furthermore, filtration in client occurs after letter is already received or is loaded; therefore thus it is heavy to remove the large volumes of letters. For the safe attack can be used anonymous remailer. When someone wants to send the insulting or threatening letter and in this case to hide its personality, it can use anonymous remailer. If man wants to send electronic letter, without revealing his domestic address of themes, who can threaten it, he can also use anonymous remailer. If he begins to suddenly obtain undesirable letters with his current address, he can forego it and take new. By one frequently utilized means of protection, used by some users Usenet, is configure its clients for reading of news in such a way that in field Reply- that (the return address) of the letter, sent by them into the group of news, is placed the false address, and real address is placed in the signature or into the telex- communications. By such means of the program of the collection of post addresses, the gathering addresses from field Reply- that, will prove to be useless. In the congress OF THE USA there was pod no several bills about the limitations to the work of such programs -moor. In one it was proposed to create the lists of foot- words and to place the word "advertisement" into the line of the theme of letter. In other it was proposed to consider it their simply illegal.

5. Protection of electronic mail

5.1. Protection from the false addresses from this it is possible to be protected with the aid of the use of coding for the connection to the letters of electronic signatures. The use of coding with the open keys is one popular method. The unidirectional hash- function of letter is ciphered, using a secret key of sender. Recipient uses the open key of sender for the interpretation of hash- function and compares him with the hash- function, calculated according to the obtained communication. This it guarantees, that the communication in reality is written by sender, and not it was changed in the way. The U.S. Government requires the use of algorithm Secure Hash Algorithm (SHA) and Digital Signature Standard, there where this is possible. But the most popular commercial programs use algorithms RC2, RC4, or RC5 firm RSA.

5.2. Protection from the interception from it it is possible to be protected with the aid of the coding of the contained communication or channel, by which it is transferred. If communication channel is encoded, then system administrators at its both ends nevertheless can read or change communications. Many different diagrams of the coding of electronic mail were proposed, but none of them became mass. One of the most popular applications is PGP. In the past use PGP was problematic, since in it was used the coding, which fell under the export ban from THE USA. The commercial version PGP includes plainly for several popular post programs, which makes with its especially convenient for the start in the letter to electronic signature and the coding of letter by client. The last versions PGP use the copywriter version of the algorithm of coding with the open keys RSA.

6. Correct use of electronic mail all employees must employ the electronic mail just as any other official means of organization. Hence it follows that when the letter is sent, both the sender and the recipient must guarantee, that interaction between them is accomplished according to the rules of interaction accepted. Interaction with the aid of the mail must not be unethical, there must not be received as conflict situation, or contain classified information.

 7. Protection of electronic letters and messaging systems the protection of letters, mail servers and programs must correspond to the importance of information, transferred by the networks. As a rule, must be achieved centralized control of the services of electronic mail. Must be developed the policy, in which would be indicated the necessary level of protection.

8. Examples the politician of safety for the electronic mail low risk user the use of services of electronic mail for purposes, clearly contradicting the interests of organization or contradicting the politicians of safety of organization is forbidden, just as its excessive use for personal purposes. The use of addresses of organization in the letter- pyramids is forbidden. Organization gives electronic mail for fulfilling by them its responsibilities its colleagues. Its limited use for personal purposes is permitted, if it does not threaten organization. The use of electronic mail in such a way that this helps to obtain personal commercial benefit, is forbidden. Manager all colleagues must have addresses of electronic mail. The reference books of electronic addresses must be accessible for the general access. If organization ensures access to the electronic mail of the external users, such as consultants, contract using or partners, they must read the policy of access to the electronic mail and be painted for this. Contents of post communications is considered confidential, with exception of the case of conducting the investigations by the organs of internal affairs. The colleague of the division of automation POP- server must be configuration so as to exclude the use of the enciphered passwords from the local machines. Average risk user electronic mail is given to the colleagues of organization only for fulfilling by them its official responsibilities. Its use for personal purposes is forbidden. The classified information or the information, which is been the property of organization, cannot be sent with the aid of the electronic mail. Only affirmed post programs can be used. It is not possible to establish anonymous remailer by employee forbidden to use anonymous remailer manager classified information or the information, which is been the property of organization, it cannot be sent with the aid of the electronic mail. If it is established that the colleague incorrectly uses electronic mail with the design, he will punished the colleague of the division of automation messaging system it must ensure only one external electronic address for each colleague. This address must not contain the name of internal system or post it must be conducted the local archive of the MIME- compatible programs for the survey of special sizes and to be accessible for the internal use. High risk user electronic mail is given to the colleagues of organization only for fulfilling its official responsibilities. Its use for personal purposes is forbidden. All electronic letters, created and on the computers of organization, are the property of organization and are not considered personal. Organization leaves after itself the right to obtain access to the electronic mail of colleagues, if to that there are sound reasons. Contents of electronic letter cannot be opened, except as for the purpose of providing safety or on the requirement of law-enforcement agencies. Users must not make possible for someone to send letters, using their identifiers. This concerns their chiefs, secretaries, assistants or other colleagues. Organization leaves after itself the right to supervise of the post sending’s of colleagues. Electronic letters can be read by organization even if they were removed by sender, and by recipient. Such communications can be used for the substantiation of punishment. Manager the reference books of the electronic addresses of colleagues cannot be made accessible to all. If the classified information or the information, which is been the property of organization, must be sent with the aid of the electronic letter, it must be encoded then so that it it could read only that, coma it was intended, with the use of the affirmed in the organization programs and algorithms. No one of visitors, volunteer contract soldiers or temporary employees does not have a right to use electronic mail of organization. Must be used coding all information, classified as critical or commercial secret, with its transfer through the open networks, such as the Internet. The outgoing communications can be selective checked in order to guarantee the observance of policy. The colleague of the division of automation the entering letters must be checked against the viruses or another RPS. Mail servers must be configuration so as to reject the letters, addressed not to the computers of organization. The periodicals of mail servers must be checked against the object of the development of the use of the unconfirmed post clients by colleagues of organization, and must report about such cases. Post clients must be configuration so that the each piece of information would sign with the aid of the digital signature of sender.

9. Storage of electronic letters the official documents of organization, transferred with the aid of the electronic mail, must be identified and they must manage, protect and be accompanied as for long, as this necessarily for the activity of organization, Audit, jurists, or for other purposes. When electronic mail - is the only method of the transfer of the official documents of company, then to them are applied the same procedures, as if they were transferred on the paper. For averting the random removal of letters, the colleagues must direct the copies of such communications into the official file or archive. Must be stored both the entering and outgoing communications with the applications. Any letter, which contains formal permission or organizations with another organization expressing agreement, must be copied into the appropriate file (or it must be done its printed copy) for protocol and Audit. Shelf-life of all letters is determined by jurists. If communications are stored too for long, organization can forced to do this information of public based on a court decision.