pmg-intro.adoc

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