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 from a sender your system does not recognize,
  91 means, that it will be temporarily rejected. Since temporary failures
  92 are built into the RFC specifications for mail delivery, a legitimate
  93 server will try to resend the email later on. This is an effective
  94 method because spammers do not queue and reattempt mail delivery as is
  95 normal for a regular Mail Transport Agent.
  96 +
  97 Greylisting can reduce e-mail traffic up to 50%. A greylisted email
  98 never reaches your mail server and thus your mail server will not send
  99 useless "Non Delivery Reports" to spammers.
 100
 101 SMTP Protocol Tests::
 102
 103 {postfix} is able to do some sophisticated SMTP protocol tests (see
 104 `man postscreen`). Most spam is sent out by zombies (malware on
 105 compromised end-user computers), and those zombies often try to
 106 maximize the amount of mails delivered. In order to do that, many of
 107 them violates the SMTP protocol specification and can thus be detected
 108 by these tests.
 109
 110 Before and After Queue Filtering::
 111
 112 {pmg} can be configured to either accept the mail, by sending a response
 113 of '250 OK', and scan it afterwards, or alternatively inspect the mail
 114 directly after it has the content and respond with a reject '554' if the
 115 mail is blocked by the rule system. These options are known as After Queue
 116 and Before Queue filtering respectively (see
 117 xref:pmgconfig_mailproxy_before_after_queue[Before and After Queue Scanning]).
 118
 119 Configurable NDR policy::
 120
 121 In certain environments it can be unacceptable to discard an email, without
 122 informing the sender about that decision. You can decide whether you want
 123 to inform the senders of blocked emails or not.
 124
 125 Virus detection
 126 ~~~~~~~~~~~~~~~
 127
 128 {pmg} integrates {clamav}, which is an open-source (GPL) antivirus
 129 engine designed for detecting Trojans, viruses, malware and other
 130 malicious threats.
 131
 132 It provides a high performance mutli-threaded scanning daemon, command
 133 line utilities for on demand file scanning, and an intelligent tool
 134 for automatic signature updates.
 135
 136
 137 Object-Oriented Rule System
 138 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 139
 140 The object-oriented rule system enables custom rules for your
 141 domains. It’s an easy but very powerful way to define filter rules by
 142 user, domains, time frame, content type and resulting action. {pmg}
 143 offers a lot of powerful objects to configure your own custom system.
 144
 145 WHO - objects::
 146
 147 Who is the sender or receiver of the e-mail?
 148
 149 WHAT - objects::
 150
 151 What is in the e-mail?
 152
 153 WHEN - objects::
 154
 155 When is the e-mail received by {pmg}?
 156
 157 ACTIONS - objects::
 158
 159 Defines the final actions.
 160
 161 Every rule has five categories FROM, TO, WHEN, WHAT and ACTION. Every
 162 of these categories can contain several objects and a direction (in,
 163 out or both).
 164
 165 Options range from simple spam and virus filter setups to
 166 sophisticated, highly customized configurations blocking certain types
 167 of e-mails and generating notifications.
 168
 169
 170 Spam Quarantine
 171 ~~~~~~~~~~~~~~~
 172
 173 Identified Spam mails can be stored to the user accessible Spam
 174 quarantine. Thus users can view and manage there Spam mails by
 175 themselves.
 176
 177
 178 Tracking and Logging
 179 ~~~~~~~~~~~~~~~~~~~~
 180
 181 The innovative Proxmox Message Tracking Center tracks and summarizes
 182 all available logs. With the web-based and user friendly management
 183 interface, the IT admins can easily overview and control all
 184 functions from a single screen.
 185
 186 The Message Tracking Center is very fast and powerful, tested on {pmg}
 187 sites processing over a million emails per day. All different log
 188 files from the last 7 days can be queried and the results are
 189 summarized by an intelligent algorithm.
 190
 191 - Arrival of the email
 192 - Proxmox filtering processing with results
 193 - Internal queue to your email server
 194 - Status of final delivery
 195
 196
 197 DKIM Signing
 198 ~~~~~~~~~~~~
 199
 200 {pmg} offers the possibility to optionally sign outgoing emails with
 201 xref:pmgconfig_mailproxy_dkim[DKIM].
 202
 203
 204 High Availability with Proxmox HA Cluster
 205 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 206
 207 To provide a 100% secure email system for your business, we developed
 208 Proxmox High Availability (HA) Cluster. The Proxmox HA Cluster uses a
 209 unique application level clustering scheme, which provides extremely
 210 good performance. Fast set-up within minutes and a simple, intuitive
 211 management keep resource needs low. After temporary failures, nodes
 212 automatically reintegrate without any operator interaction.
 213
 214 LDAP integration
 215 ~~~~~~~~~~~~~~~~
 216
 217 It is possible to query user and group data from LDAP servers. This
 218 may be used to build special filter rules, or just to provide
 219 authentication services for the Spam quarantine GUI.
 220
 221
 222 Fetchmail integration
 223 ~~~~~~~~~~~~~~~~~~~~~
 224
 225 {pmg} allows you to fetch mail from other IMAP or POP3 servers.
 226
 227
 228 Flexible User Management
 229 ~~~~~~~~~~~~~~~~~~~~~~~~
 230
 231 The administration interface uses a role based access control scheme,
 232 using the following roles:
 233
 234 Superuser::
 235
 236 This role is allowed to do everything (reserved for user 'root').
 237
 238 Administrator::
 239
 240 Full access to mail filter setup, but not allowed to change network setup.
 241
 242 Quarantine Manager::
 243
 244 Is able to view and manage the Spam Quarantine.
 245
 246 Auditor::
 247
 248 Has read-only access to the whole configuration, can access logs and
 249 view statistics.
 250
 251
 252 Your benefit with {pmg}
 253 -----------------------
 254
 255 * Open source software
 256 * No vendor lock-in
 257 * Linux kernel
 258 * Fast installation and easy-to-use
 259 * Web-based management interface
 260 * REST API
 261 * Huge active community
 262 * Low administration costs and simple deployment
 263
 264
 265 include::getting-help.adoc[]