Secure emails with UserGate mail server

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Introduction :
Mail Server - one of the most important links in the software part of the IT infrastructure company. Times when email is used for corporate purposes, was chosen by the free service, go to the past. The reason for this - the development and cheaper software for deploying a mail server even within a small company. On one such product and today we are going - Usergate MailServer.

Preparation work :
E-mail server from Usergate is a software product for use on computers running Windows XP/2003 Server / Vista. The installer allows to install the product components, the registration system services and database statistics, running on the database PostgreSQL. At the end of the installer from the user will need in the administration console to create a connection to the server, add the domain on which the organization's network, as well as create mailboxes for users. Anti-spam service connected automatically by default, access to the web interface is organized as a standard way. Nevertheless, we consider a more detailed mechanism of working with Usergate MailServer.

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Configuring the server :
Clearly, for the successful installation and operation of a mail server on your network must be open (open ports) for protocols POP3, IMAP4, SMTP, HTTP, HTTPS, SSL, and TCP 2222 for the administration console. By default, the console is located on localhost and have one Administrator account without a password (you can register in the XML-configuration file or when you connect the console in the "Server Settings"). To console you can connect both with all IP-addresses, and with a certain group.

All server settings and messages stored in the database, which operates as a separate service UserGate Mail Database Service with open access to it on TCP port 5432. By default, you create three accounts - for the root database administrator, database access messages passing through the web interface and those that pass through e-mail clients. Server statistics can be deployed on the same server, where Usergate MailServer, and handle requests from multiple domains in several streams with the option enabled or disabled caching. It is possible to send all correspondence to the selected reserve address without checking them for viruses and spam. The main scope of work to configure the mail server refers to the direction of domain settings. In general, Usergate MailServer this mechanism add no different conceptually from any other mail server (name, aliases, quota limit messages, spam filtering, address to send the error messages and so forth). Of the nice features here is the synchronization is not only the internal user base, but also with the LDAP-directory (user accounts from Active Directory).


Set up e-mail :
The main thing in the mail server - this is how the solution works not only with incoming correspondence, but also handles outgoing mail. In the constant struggle with spam and fraudulent mailings, it is important to the mail server was able to identify such objects and not be made because of faulty configuration itself in the spread of junk e-mail link. In Usergate MailServer present the necessary minimum of these settings, so you can easily create the correct line of delivery of letters. The administrator can specify the number of attempts to deliver messages to the addressee, the period of pauses between them, and also appeared to be Usergate MailServer to other mail servers. By default, the program is set that SMTP-server is running at MX-delivery, where each message is delivered directly to the server, acting as the recipient's domain. Nevertheless, the administrator can specify a proxy server, username and password, if authentication is required. Nevertheless, it should be understood that the wrong configuration, mail relay, all letters can be defined as spam, since the IP-address will be recorded in the gray list. We are talking about sending letters specifying the options - within the domain (Local - Local), inside the local domain to external domains (Local - Remote), receiving messages from external domains (Remote - Local). The system administrator has the right to produce more fine-tuning the server, indicating the range of allowed IP-addresses, the maximum allowable number of recipients, the maximum depth of delivery (number of copies of forwarded messages, to avoid looping in the mail processing), the amount of log that records all transactions on the server.

Accounts for users created in a classic case - you must specify the login name of the mail domain that will include a box, alternate names, password, quota-box, the level of access to the administration console, as well as forward-mail to receive messages. However, if a mail server installed on the machine that is included in the Active Directory domain and in the properties of the mail domain is set up LDAP Sync, enter a password to the email account is not required. In this case, to authenticate a user will use a password on the domain. Note that the system can be registered and remote users, ie, the owners of the external mail addresses (for them, specify the parameters collection of correspondence to a local account). Organize delivery in Usergate MailServer is also not difficult. There are three modes of operation of such a service - when the letters are distributed to all participants, but any user can write to the external address to the mailing list, the same way, but without the ability to receive email from outside, centralized, when none of the distribution is not entitled to post to the list. Routes are also given a fairly simple way - in Settings Server system administrator must open the relevant section and set the necessary parameters for the remote SMTP-server, the number of delivery attempts and timeouts, the email relay, if you are using external SMTP-server. By correspondence also applies a large number of filters that allow you to flexibly customize the rules for sorting messages by multiple criteria (body, attachments, subject, and so on).

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Serving Interface :
Of course, any e-mail client must be serviced, ie, to produce some work to support the software in proper condition. In Usergate MailServer for this are the backup service, built-in antivirus engine, anti-spam modules and system logs. Consider their capabilities. Backup service allows you to save the contents of a folder with correspondence, files, server settings and the cast of the database. The technique involves creating a backup of full backups and differential backups. The resulting files have the extension ZIP. The user can specify the sequence of creating the necessary copies, backup timing of life (after which it will be removed), the start time of the utility to back up (automatically, for example, after a power outage, the mail server does not initiate recovery).

In Usergate MailServer uses two anti-virus module, familiar to many from the experience of working with the flagship products of UserGate Proxy & Firewall. This solution from Panda Security and Kaspersky Lab that test SMTP-traffic (outgoing emails are not checked). The implementation of these modules is similar to other products on Entensys - laconic customize the behavior of the server when a virus is detected, as well as limiting the size of the letter, which is subject to verification. UserGate Mail Server supports simultaneous operation of two anti-virus modules (although, in our view, there is no special needs). In this sequence of checks is determined by the rules of Message Rules, given by the administrator UserGate Mail Server.

Key optional mail server Usergate MailServer - Anti-Spam extended system provided directly by four technologies - based on dynamic blacklist »DNSBL (DNS blacklist), SURBL (Spam URI blacklist),« gray lists "and" slowing down »(tarpitting). The first technology is a service that receives information about IP-addresses from which spam-listed activity. In this case, mail filters that support the use of DNSBL, form a query to the provider of the "black list" containing the address of the sender, as well as mail servers, through which passes the letter on the way to the recipient. If the query reveals that the address contained in the "black list", then the system concludes that the letter is very likely the usual spam. Some ISPs blacklist, along with lists of spammers track address from which the distribution of viruses, Trojans, network worms, unauthorized remote control software and other malicious software. The second technology is designed to detect spam based on the URL-addresses, which is in the body. The module extracts from the message body, removes domain component (second or third level), adds name suffix SURBL and performs a DNS query to the address SURBL-server. Allowed verification of virtual hosting and special zones for third-level domains. Gray lists used delaying mechanism to receive email - incoming mail is accepted immediately, but after a certain period of time after the sender sent a message asking to try again. In this case, the information is stored in a magazine and then checked against the repeated receipt. Spammers do not use the re-sending to the same address. Slowing down - a simple method based on filtering messages with lots of recipients in one message. If this number exceeds the threshold, the subsequent receipt from the server start to occur with a specified delay. In addition, Usergate MailServer uses two branded solutions for anti-spam - SpamAssassin (based on a points system) and Commtouch (Commtouch's Anti-Spam Gateway), filter based on the company's algorithm RPD (Recurrent-Pattern Detection), identifies spam based on its main features - on its prevalence, taking as a basis for its contents.


Conclusion :
In general, Usergate MailServer is a flexible and fairly simple solution for the exchange of mail within an organization of small and medium businesses. The product has advanced protection against spam and viruses, and also maintains a minimum of functions to work.