pmg-intro.adoc

   1 Introduction
   2 ============
   3
   4 What is {pmg}?
   5 --------------
   6
   7 Email security begins at the gateway, by controlling all incoming and
   8 outgoing email messages. {pmg} addresses the full spectrum of
   9 unwanted email traffic, focusing on spam and virus detection. {pmg}
  10 provides a powerful and affordable server solution to eliminate spam and
  11 viruses, and block undesirable content from your email system. All
  12 products are self-installing and can be used without deep knowledge of
  13 Linux.
  14
  15 image::images/Proxmox_Mail_Gateway_Mailprocessing_final_1024.png[]
  16
  17 Features
  18 --------
  19
  20 [[intro_spam_detection]]
  21 Spam detection
  22 ~~~~~~~~~~~~~~
  23
  24 {pmg} uses a wide variety of local and network tests to identify spam
  25 mail. Here is a short list of used filtering methods:
  26
  27 Receiver Verification::
  28
  29 Many of the junk messages reaching your network are emails to
  30 non-existent users. {pmg} detects these emails on the SMTP
  31 level, before they are transferred to your network. This
  32 reduces the traffic to be analyzed for spam and viruses by up to 90% and
  33 reduces the working load on your mail servers and scanners.
  34
  35 Sender policy framework (SPF)::
  36
  37 Sender Policy Framework (SPF) is an open standard for validating
  38 emails and preventing sender IP address forgery. SPF allows the
  39 administrator of an internet domain to specify which computers are
  40 authorized to send emails with a given domain, by creating a specific
  41 SPF record in the Domain Name System (DNS).
  42
  43 DNS-based Blackhole List::
  44
  45 A DNS-based Blackhole List (DNSBL) is a means by which an internet
  46 site may publish a list of IP addresses, in a format which can be
  47 easily queried by computer programs on the Internet. The technology is
  48 built on top of the Domain Name System. DNSBLs are used to publish
  49 lists of addresses linked to spamming.
  50
  51 SMTP Whitelist::
  52
  53 Exclude senders from SMTP blocking. To prevent all SMTP checks
  54 (Greylisting, Receiver Verification, SPF and DNSBL) and accept all
  55 emails for analysis in the filter rule system, you can add the
  56 following to this list: Domains (Sender/Receiver), Mail address
  57 (Sender/Receiver), Regular Expression (Sender/Receiver), IP address
  58 (Sender), IP network (Sender).
  59
  60 Bayesian Filter - Automatically trained statistical filters::
  61
  62 Certain words have a higher probability of occurring in spam
  63 emails than in legitimate emails. By being trained to
  64 recognize those words, the Bayesian filter checks every email and adjusts the
  65 probabilities of it being a spam word or not in its database. This is
  66 done automatically.
  67
  68 Black- and Whitelists::
  69
  70 Black- and Whitelists are an access control mechanism to accept,
  71 block, or quarantine emails to recipients. This allows you to tune the
  72 rule-system by applying different objects like domains, email address,
  73 regular expression, IP Network, LDAP Group, and others.
  74
  75 Auto-learning algorithm::
  76
  77 {pmg} gathers statistical information about spam
  78 emails. This information is used by an auto-learning algorithm, meaning the
  79 system becomes smarter over time.
  80
  81 Spam URI Real-time Block List (SURBL)::
  82
  83 SURBLs are used to detect spam, based on the URIs in the message body (usually
  84 websites). This makes them different from most other Real-time
  85 Blocklists, because SURBLs are not used to block spam senders. SURBLs
  86 allow you to block messages that have spam hosts which are mentioned
  87 in message bodies.
  88
  89 Greylisting::
  90
  91 Greylisting an email means that unknown senders are intentionally temporarily
  92 rejected. Since temporary failures are part of the specifications for mail
  93 delivery, a legitimate server will try to resend the email later on. Spammers,
  94 on the other hand, do not queue and reattempt mail delivery. A greylisted email
  95 never reaches your mail server and thus your mail server will not send useless
  96 "Non Delivery Reports" to spammers. Additionally, greylisted mail is not
  97 analyzed by the antivirus and spam-detector engines, which saves resources.
  98 +
  99 A mail is greylisted if it is the first mail from a sender to a receiver
 100 coming from a particular IP network. You can configure which IP addresses
 101 belong to the same network, by setting an appropriate netmask for greylisting.
 102
 103 SMTP Protocol Tests::
 104
 105 {postfix} is able to do some sophisticated SMTP protocol tests (see
 106 `man postscreen`). Most spam is sent out by zombies (malware on
 107 compromised end-user computers), and those zombies often try to
 108 maximize the amount of mails delivered. In order to do that, many of
 109 them violate the SMTP protocol specification and thus can be detected
 110 by these tests.
 111
 112 Before and After Queue Filtering::
 113
 114 {pmg} can be configured to either accept the mail, by sending a response
 115 of '250 OK', and scan it afterwards, or alternatively inspect the mail
 116 directly after it has the content and respond with a reject '554' if the
 117 mail is blocked by the rule system. These options are known as After Queue
 118 and Before Queue filtering respectively (see
 119 xref:pmgconfig_mailproxy_before_after_queue[Before and After Queue Scanning]).
 120
 121 Configurable NDR policy::
 122
 123 In certain environments, it can be unacceptable to discard an email, without
 124 informing the sender about that decision. You can decide whether you want
 125 to inform the senders of blocked emails or not.
 126
 127 Virus detection
 128 ~~~~~~~~~~~~~~~
 129
 130 {pmg} integrates {clamav}, which is an open-source (GPL) antivirus
 131 engine, designed for detecting Trojans, viruses, malware, and other
 132 malicious threats.
 133
 134 It provides a high performance, multi-threaded scanning daemon, command
 135 line utilities for on demand file scanning, and an intelligent tool
 136 for automatic signature updates.
 137
 138
 139 Object-Oriented Rule System
 140 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 141
 142 The object-oriented rule system enables custom rules for your
 143 domains. It’s an easy but very powerful way to define filter rules by
 144 user, domains, time frame, content type and resulting action. {pmg}
 145 offers a lot of powerful objects to configure your own custom system.
 146
 147 WHO - objects::
 148
 149 Who is the sender or receiver of the email?
 150
 151 WHAT - objects::
 152
 153 What is in the email?
 154
 155 WHEN - objects::
 156
 157 When was the email received by {pmg}?
 158
 159 ACTIONS - objects::
 160
 161 Defines the final actions.
 162
 163 Every rule has five categories FROM, TO, WHEN, WHAT and ACTION. Each
 164 of these categories can contain several objects and a direction (in,
 165 out or both).
 166
 167 Options range from simple spam and virus filter setups to
 168 sophisticated, highly customized configurations, blocking certain types
 169 of emails and generating notifications.
 170
 171 Web-based Management Interface
 172 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 173
 174 {pmg} makes email security and filtering simple to manage. The web-based
 175 management interface allows you to set up and maintain even a complex mail
 176 system with ease.
 177
 178 [thumbnail="pmg-gui-dashboard.png"]
 179
 180 There is no need to install a separate management tool. Any modern internet
 181 browser is sufficient.
 182
 183 Spam Quarantine
 184 ~~~~~~~~~~~~~~~
 185
 186 Identified spam mails can be stored in the user-accessible Spam Quarantine.
 187 Thus, users can view and manage their spam mails by themselves.
 188
 189
 190 Tracking and Logging
 191 ~~~~~~~~~~~~~~~~~~~~
 192
 193 The innovative Proxmox Message Tracking Center tracks and summarizes
 194 all available logs. With the web-based and user-friendly management
 195 interface, IT admins can easily view and control all
 196 functions from a single screen.
 197
 198 The Message Tracking Center is fast and powerful. It has been tested on
 199 {pmg} sites which process over a million emails per day. All log
 200 files from the last 7 days can be queried, and the results are
 201 summarized by an intelligent algorithm.
 202
 203 The logged information includes:
 204
 205 - Arrival of the email
 206 - Proxmox filter processing with results
 207 - Internal queue to your email server
 208 - Status of final delivery
 209
 210
 211 DKIM Signing
 212 ~~~~~~~~~~~~
 213
 214 {pmg} offers the possibility to optionally sign outgoing emails with
 215 xref:pmgconfig_mailproxy_dkim[DKIM].
 216
 217
 218 High Availability with Proxmox HA Cluster
 219 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 220
 221 To provide a 100% secure email system for your business, we developed
 222 Proxmox High Availability (HA) Cluster. The Proxmox HA Cluster uses a
 223 unique application-level clustering scheme, which provides extremely
 224 good performance. It is quick to set-up and the simple, intuitive
 225 management interface keeps resource requirements low. After temporary failures,
 226 nodes automatically reintegrate without any operator interaction.
 227
 228 LDAP Integration
 229 ~~~~~~~~~~~~~~~~
 230
 231 It is possible to query user and group data from LDAP servers. This may be
 232 used to build special filter rules, or simply to provide authentication services
 233 for the Spam Quarantine GUI.
 234
 235
 236 Fetchmail Integration
 237 ~~~~~~~~~~~~~~~~~~~~~
 238
 239 {pmg} allows you to fetch mail from other IMAP or POP3 servers.
 240
 241
 242 Flexible User Management
 243 ~~~~~~~~~~~~~~~~~~~~~~~~
 244
 245 The administration interface uses a role-based access control scheme,
 246 using the following roles:
 247
 248 Superuser::
 249
 250 This role is allowed to do everything (reserved for user 'root').
 251
 252 Administrator::
 253
 254 Full access to the mail filter setup, but not allowed to alter the network
 255 setup.
 256
 257 Quarantine Manager::
 258
 259 Is able to view and manage the Spam Quarantine.
 260
 261 Auditor::
 262
 263 Has read-only access to the whole configuration, can access logs and
 264 view statistics.
 265
 266 Helpdesk::
 267
 268 Combines permissions of the 'Auditor' and the 'Quarantine Manager' role.
 269
 270
 271 Your benefit with {pmg}
 272 -----------------------
 273
 274 * Open-source software
 275 * No vendor lock-in
 276 * Linux kernel
 277 * Fast installation and easy-to-use
 278 * Web-based management interface
 279 * REST API
 280 * Huge, active community
 281 * Low administration costs and simple deployment
 282
 283
 284 include::getting-help.adoc[]