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 unknown senders are intentionally temporarily
  91 rejected. Since temporary failures are part of the specifications for mail
  92 delivery, a legitimate server will try to resend the email later on. Spammers
  93 on the other hand, do not queue and reattempt mail delivery. A greylisted email
  94 never reaches your mail server and thus your mail server will not send useless
  95 "Non Delivery Reports" to spammers. Additionally greylisted mail is not
  96 analyzed by the antivirus and spam-detector engines, which saves resources.
  97 +
  98 A mail is greylisted if it is the first mail from a sender to a receiver
  99 coming from a particular IP network. You can configure which IP addresses
 100 belong to the same network, by setting an appropriate netmask for greylisting.
 101
 102 SMTP Protocol Tests::
 103
 104 {postfix} is able to do some sophisticated SMTP protocol tests (see
 105 `man postscreen`). Most spam is sent out by zombies (malware on
 106 compromised end-user computers), and those zombies often try to
 107 maximize the amount of mails delivered. In order to do that, many of
 108 them violate the SMTP protocol specification and thus can get detected
 109 by these tests.
 110
 111 Before and After Queue Filtering::
 112
 113 {pmg} can be configured to either accept the mail, by sending a response
 114 of '250 OK', and scan it afterwards, or alternatively inspect the mail
 115 directly after it has the content and respond with a reject '554' if the
 116 mail is blocked by the rule system. These options are known as After Queue
 117 and Before Queue filtering respectively (see
 118 xref:pmgconfig_mailproxy_before_after_queue[Before and After Queue Scanning]).
 119
 120 Configurable NDR policy::
 121
 122 In certain environments it can be unacceptable to discard an email, without
 123 informing the sender about that decision. You can decide whether you want
 124 to inform the senders of blocked emails or not.
 125
 126 Virus detection
 127 ~~~~~~~~~~~~~~~
 128
 129 {pmg} integrates {clamav}, which is an open-source (GPL) antivirus
 130 engine designed for detecting Trojans, viruses, malware and other
 131 malicious threats.
 132
 133 It provides a high performance mutli-threaded scanning daemon, command
 134 line utilities for on demand file scanning, and an intelligent tool
 135 for automatic signature updates.
 136
 137
 138 Object-Oriented Rule System
 139 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 140
 141 The object-oriented rule system enables custom rules for your
 142 domains. It’s an easy but very powerful way to define filter rules by
 143 user, domains, time frame, content type and resulting action. {pmg}
 144 offers a lot of powerful objects to configure your own custom system.
 145
 146 WHO - objects::
 147
 148 Who is the sender or receiver of the e-mail?
 149
 150 WHAT - objects::
 151
 152 What is in the e-mail?
 153
 154 WHEN - objects::
 155
 156 When is the e-mail received by {pmg}?
 157
 158 ACTIONS - objects::
 159
 160 Defines the final actions.
 161
 162 Every rule has five categories FROM, TO, WHEN, WHAT and ACTION. Every
 163 of these categories can contain several objects and a direction (in,
 164 out or both).
 165
 166 Options range from simple spam and virus filter setups to
 167 sophisticated, highly customized configurations blocking certain types
 168 of e-mails and generating notifications.
 169
 170
 171 Spam Quarantine
 172 ~~~~~~~~~~~~~~~
 173
 174 Identified Spam mails can be stored to the user-accessible Spam
 175 quarantine. Thus, users can view and manage their Spam mails by
 176 themselves.
 177
 178
 179 Tracking and Logging
 180 ~~~~~~~~~~~~~~~~~~~~
 181
 182 The innovative Proxmox Message Tracking Center tracks and summarizes
 183 all available logs. With the web-based and user-friendly management
 184 interface, IT admins can easily overview and control all
 185 functions from a single screen.
 186
 187 The Message Tracking Center is very fast and powerful, tested on {pmg}
 188 sites processing over a million emails per day. All different log
 189 files from the last 7 days can be queried and the results are
 190 summarized by an intelligent algorithm.
 191
 192 The logged information includes:
 193
 194 - Arrival of the email
 195 - Proxmox filtering processing with results
 196 - Internal queue to your email server
 197 - Status of final delivery
 198
 199
 200 DKIM Signing
 201 ~~~~~~~~~~~~
 202
 203 {pmg} offers the possibility to optionally sign outgoing emails with
 204 xref:pmgconfig_mailproxy_dkim[DKIM].
 205
 206
 207 High Availability with Proxmox HA Cluster
 208 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 209
 210 To provide a 100% secure email system for your business, we developed
 211 Proxmox High Availability (HA) Cluster. The Proxmox HA Cluster uses a
 212 unique application level clustering scheme, which provides extremely
 213 good performance. Fast set-up within minutes and a simple, intuitive
 214 management keep resource needs low. After temporary failures, nodes
 215 automatically reintegrate without any operator interaction.
 216
 217 LDAP integration
 218 ~~~~~~~~~~~~~~~~
 219
 220 It is possible to query user and group data from LDAP servers. This
 221 may be used to build special filter rules, or just to provide
 222 authentication services for the Spam quarantine GUI.
 223
 224
 225 Fetchmail integration
 226 ~~~~~~~~~~~~~~~~~~~~~
 227
 228 {pmg} allows you to fetch mail from other IMAP or POP3 servers.
 229
 230
 231 Flexible User Management
 232 ~~~~~~~~~~~~~~~~~~~~~~~~
 233
 234 The administration interface uses a role-based access control scheme,
 235 using the following roles:
 236
 237 Superuser::
 238
 239 This role is allowed to do everything (reserved for user 'root').
 240
 241 Administrator::
 242
 243 Full access to mail filter setup, but not allowed to change network setup.
 244
 245 Quarantine Manager::
 246
 247 Is able to view and manage the Spam Quarantine.
 248
 249 Auditor::
 250
 251 Has read-only access to the whole configuration, can access logs and
 252 view statistics.
 253
 254
 255 Your benefit with {pmg}
 256 -----------------------
 257
 258 * Open source software
 259 * No vendor lock-in
 260 * Linux kernel
 261 * Fast installation and easy-to-use
 262 * Web-based management interface
 263 * REST API
 264 * Huge active community
 265 * Low administration costs and simple deployment
 266
 267
 268 include::getting-help.adoc[]