Table Of ContentV e r s i o n 3 . 3
Barracuda Spam Firewall Administrator’s Guide
Barracuda Networks Inc.
385 Ravendale Drive
Mountain View, CA 94043
http://www.barracudanetworks.com
Copyright Notice
Copyright 2004-2006, Barracuda Networks
www.barracudanetworks.com
v3.3-060504-03-617
All rights reserved. Use of this product and this manual is subject to license. Information in this document is subject to change without notice.
Trademarks
Barracuda Spam Firewall is a trademark of Barracuda Networks. All other brand and product names mentioned in this document are registered
trademarks or trademarks of their respective holders.
2 Spam Firewall Administrator’s Guide
Contents
Chapter 1 - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Energize Updates Minimize Administration and Maximize Protection . . . . . 10
Understanding Spam Scoring. . . . . . . . . . . . . . . . . . . . . . . . 11
Inbound and Outbound Modes . . . . . . . . . . . . . . . . . . . . . . . . . 12
Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Warranty Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Barracuda Spam Firewall Models. . . . . . . . . . . . . . . . . . . . . . . . . . 13
Locating Information in this Document . . . . . . . . . . . . . . . . . . . . . . . 15
Basic Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Block/Accept Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Users Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Domains Tab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Advanced Tab. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Chapter 2 - Getting Started . . . . . . . . . . . . . . . . . . . . . . 19
Initial Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Checklist for Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Required Equipment for Installation. . . . . . . . . . . . . . . . . . . . . . . 20
Install the Barracuda Spam Firewall. . . . . . . . . . . . . . . . . . . . . . . 20
Configure the System IP Address and Network Settings . . . . . . . . . . . . 21
Configure your Corporate Firewall . . . . . . . . . . . . . . . . . . . . . . . 21
Configure the Barracuda Spam Firewall . . . . . . . . . . . . . . . . . . . . 22
Set the Administrative Options . . . . . . . . . . . . . . . . . . . . . . . . . 23
Update the System Firmware . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Verify your Subscription Status . . . . . . . . . . . . . . . . . . . . . . . . . 24
Route Incoming Email to the Barracuda Spam Firewall. . . . . . . . . . . . . 25
Port Forwarding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
MX Records. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Tune the Default Spam Settings. . . . . . . . . . . . . . . . . . . . . . . . . 26
Installation Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Barracuda Spam Firewall Behind Corporate Firewall. . . . . . . . . . . . . . 28
Barracuda Spam Firewall in the DMZ. . . . . . . . . . . . . . . . . . . . . . 29
Changing the Operating Mode to Outbound . . . . . . . . . . . . . . . . . . 30
Basic Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Setting up your Email Server as a Smart/Relay Host. . . . . . . . . . . . 31
Enable Smart Host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Disable Smart Host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Changing Outbound to Inbound Mode . . . . . . . . . . . . . . . . . . . . . 32
Basic Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Review the Administrative Options . . . . . . . . . . . . . . . . . . . . . 33
Route Incoming and Outgoing Email to the Barracuda Spam Firewall . . . 33
iii
Chapter 3 - Basic Tab . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Monitoring System Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Using the Status page. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Email Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Performance Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Subscription Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Hourly and Daily Mail Statistics . . . . . . . . . . . . . . . . . . . . . . . . . 38
Understanding the Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . 38
Message Log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Monitoring the Message Log . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Classifying Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Overview of the Message Log. . . . . . . . . . . . . . . . . . . . . . . . . . 41
Changing the Viewing Preferences of the Message Log . . . . . . . . . . . . 42
Viewing Message Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Clearing the Message Log . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Spam Scoring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Configuring the Global Spam Scoring Limits . . . . . . . . . . . . . . . . . . 44
Specifying the Subject Text and Priority of Tagged Messages . . . . . . . . . 45
Changing Notifications to Senders . . . . . . . . . . . . . . . . . . . . . . . 45
Spam Bounce (NDR) Configuration. . . . . . . . . . . . . . . . . . . . . 45
Virus Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Enabling and Disabling Virus Checking and Notification . . . . . . . . . . . . 46
Quarantine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Setting Up Quarantine Policies . . . . . . . . . . . . . . . . . . . . . . . . . 47
Specifying the Quarantine Type. . . . . . . . . . . . . . . . . . . . . . . . . 47
Specifying the Global Quarantine Settings . . . . . . . . . . . . . . . . . . . 48
Specifying the Per-User Quarantine Settings . . . . . . . . . . . . . . . . . . 49
IP Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Configuring System IP Information . . . . . . . . . . . . . . . . . . . . . . . 50
Administration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Controlling Access to the Administration Interface . . . . . . . . . . . . . . . 52
Changing the Password of the Administration Account. . . . . . . . . . . . . 52
Limiting Access to the Administration Interface and API . . . . . . . . . . . . 52
Allowing the Message Body in the Message Log . . . . . . . . . . . . . . . . 53
Changing the Web Interface Port and Session Expiration Length . . . . . . . 53
Shutting Down the System . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Resetting the System Using the Front Panel . . . . . . . . . . . . . . . . . . 54
Automating the Delivery of System Alerts and Notifications . . . . . . . . . . 54
Changing the Operation Mode of the System. . . . . . . . . . . . . . . . . . 54
Bayesian / Intent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Enabling Users to Classify Messages from a Mail Client . . . . . . . . . . . . 56
Using the Microsoft Outlook and Lotus Notes Plug-in. . . . . . . . . . . . . . 57
Managing the Bayesian Database . . . . . . . . . . . . . . . . . . . . . . . 57
Resetting the Bayesian Database. . . . . . . . . . . . . . . . . . . . . . . . 57
Sending Spam Messages to Barracuda Networks . . . . . . . . . . . . . . . 58
Enabling Intent Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Reducing Backscatter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Additional Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
iv Barracuda Spam Firewall Administrator’s Guide
Chapter 4 - Using the Block and Accept Filters . . . . . . . 61
Subscribing to Blacklist Services . . . . . . . . . . . . . . . . . . . . . . . . 61
Blacklist Services Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . 62
What Happens if your Domain or IP Address is on a Blacklist . . . . . . . . . 63
IP Address Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Sender Domain Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Sender Email Address Filters . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Recipient Email Address Filters. . . . . . . . . . . . . . . . . . . . . . . . . 65
Attachment Type Filters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Subject Line Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Body Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Header Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Chapter 5 - Managing Accounts and Domains . . . . . . . . 71
How the Barracuda Spam Firewall Creates New Accounts. . . . . . . . . . . 71
Viewing User Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Using Filters to Locate Accounts . . . . . . . . . . . . . . . . . . . . . . . . 73
Editing User Accounts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Removing Invalid User Accounts . . . . . . . . . . . . . . . . . . . . . . . . 74
Assigning Features to User Accounts. . . . . . . . . . . . . . . . . . . . . . 74
Overriding the Quarantine Settings for Specific User Accounts. . . . . . . . . 75
Setting Retention Policies. . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Adding New Domains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Editing Domain Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Chapter 6 - Managing Your Quarantine Inbox . . . . . . . . . 79
Receiving Messages from the Barracuda Spam Firewall . . . . . . . . . . . . 79
Greeting Message. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Quarantine Summary Report . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Using the Quarantine Interface . . . . . . . . . . . . . . . . . . . . . . . . . 80
Logging into the Quarantine Interface. . . . . . . . . . . . . . . . . . . . . . 81
Managing your Quarantine Inbox . . . . . . . . . . . . . . . . . . . . . . . . 81
Changing your User Preferences . . . . . . . . . . . . . . . . . . . . . . . . 82
Changing your Account Password . . . . . . . . . . . . . . . . . . . . . . . 82
Changing Your Quarantine Settings. . . . . . . . . . . . . . . . . . . . . . . 82
Enabling and Disabling Spam Scanning of your Email . . . . . . . . . . . . . 83
Adding Mail Addresses and Domains to Your Whitelist and Blacklist . . . 84
Changing the Language of the Quarantine Interface . . . . . . . . . . . . 85
Chapter 7 - Configuring A Domain . . . . . . . . . . . . . . . . . 87
Domain Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Chapter 8 - Setting Up LDAP . . . . . . . . . . . . . . . . . . . . . 89
Using LDAP to Authenticate Message Recipients . . . . . . . . . . . . . . . 89
Using LDAP for User Authentication . . . . . . . . . . . . . . . . . . . . . . 89
v
Impact of a Down LDAP Server. . . . . . . . . . . . . . . . . . . . . . . . . 92
Common LDAP Settings for Standard Mail Servers. . . . . . . . . . . . . . . 92
Chapter 9 - Advanced Administration . . . . . . . . . . . . . . 93
Email Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Modifying the Email Protocol Settings. . . . . . . . . . . . . . . . . . . . . . 94
Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Configuring Message Rate Control . . . . . . . . . . . . . . . . . . . . . . . 96
Explicit Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Activating Individual Accounts. . . . . . . . . . . . . . . . . . . . . . . . . . 97
Backup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Backing Up and Restoring System Configuration. . . . . . . . . . . . . . . . 98
Performing Desktop Backups . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Automating Backups (inbound mode only) . . . . . . . . . . . . . . . . . . . 99
Restoring from a Backup File . . . . . . . . . . . . . . . . . . . . . . . . . 100
Energize Updates. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Updating Spam and Virus Definitions Using Energize Updates. . . . . . . . 101
Spam Definition Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Virus Definition Updates. . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Firmware Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Updating the System Firmware Version. . . . . . . . . . . . . . . . . . . . 103
Appearance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Customizing the Appearance of the Administration Interface. . . . . . . . . 104
Syslog. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Using a Syslog Server to Centrally Manage System Logs . . . . . . . . . . 105
Outbound / Relay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
Setting up Trusted Relays and SASL/SMTP Authentication . . . . . . . . . 106
Outbound Footer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Customizing the Outbound Footer . . . . . . . . . . . . . . . . . . . . . . 108
Advanced IP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Configuring the Network Interfaces on Models 600 and Above. . . . . . . . 109
Configuring Static Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Clustering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
Setting Up Clustered and Standby Systems . . . . . . . . . . . . . . . . . .110
Cluster Set up Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
Data Propagated to the Clustered Systems. . . . . . . . . . . . . . . . . . .111
Field Descriptions for the Clustering Page . . . . . . . . . . . . . . . . . . .112
Impact of Changing the IP Address of a Clustered System. . . . . . . . . . .113
Single Sign-On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114
Implementing Single Sign-On. . . . . . . . . . . . . . . . . . . . . . . . . .114
SSL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
Enabling SSL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .116
Regional Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
Detecting Spam in Chinese and Japanese Messages . . . . . . . . . . . . .119
Bounce / NDR Messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Customizing Non-Delivery Reports (NDRs). . . . . . . . . . . . . . . . . . 120
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Generating System Reports. . . . . . . . . . . . . . . . . . . . . . . . . . 123
Displaying and Emailing Reports . . . . . . . . . . . . . . . . . . . . . . . 123
vi Barracuda Spam Firewall Administrator’s Guide
Automating the Delivery of Daily System Reports . . . . . . . . . . . . . . 123
Specifying Report Properties . . . . . . . . . . . . . . . . . . . . . . . . . 124
Example Report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
SMTP / TLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Enabling SMTP over TLS/SSL . . . . . . . . . . . . . . . . . . . . . . . . 126
Task Manager. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Using the Task Manager to Monitor System Tasks . . . . . . . . . . . . . . 127
Recovery Console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Replacing a Failed System . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Rebooting the System in Recovery Mode. . . . . . . . . . . . . . . . . . . 128
Tasks to Perform Before Rebooting in Recovery Mode. . . . . . . . . . . . 128
Performing a System Recovery or Hardware Test . . . . . . . . . . . . . . 129
Reboot Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Chapter 10 - Outbound . . . . . . . . . . . . . . . . . . . . . . . . 131
Tabs and Pages Supporting Outbound Mode. . . . . . . . . . . . . . . . . 131
About Outbound Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Viewing Outbound Messages in the Message Log . . . . . . . . . . . . . . 133
Changing the Footers on Outbound Messages. . . . . . . . . . . . . . . . 133
Specifying Allowed Senders. . . . . . . . . . . . . . . . . . . . . . . . . . 134
Specifying Allowed Senders by Domain and IP Address . . . . . . . . . . . 134
Specifying Allowed Senders Using SMTP Authentication. . . . . . . . . . . 135
Additional Email Protocol Settings for Outbound Mode. . . . . . . . . . . . 135
Enabling Intent Analysis and Spam Scoring . . . . . . . . . . . . . . . . . 136
Managing the Quarantine Box . . . . . . . . . . . . . . . . . . . . . . . . 137
Sending NDRs for Quarantined Messages . . . . . . . . . . . . . . . . . . 137
Viewing and Classifying Quarantined Messages . . . . . . . . . . . . . . . 137
Using Filters to Locate Specific Messages . . . . . . . . . . . . . . . . . . 138
Configuring Message Rate Control . . . . . . . . . . . . . . . . . . . . . . 138
Adding a Relay Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
Setting Up Subject and Body Filtering . . . . . . . . . . . . . . . . . . . . 140
Appendix 1 - Regular Expressions . . . . . . . . . . . . . . . . 141
Using Special Characters in Expressions. . . . . . . . . . . . . . . . . . . 142
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Appendix 2 - Limited Warranty and Licensing . . . . . . . 145
Exclusive Remedy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Exclusions and Restrictions. . . . . . . . . . . . . . . . . . . . . . . . . . 146
Open Source Licensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Appendix 3 - Compliance . . . . . . . . . . . . . . . . . . . . . . 149
Notice for the USA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Notice for Canada. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Notice for Europe (CE Mark) . . . . . . . . . . . . . . . . . . . . . . . . . 149
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
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viii Barracuda Spam Firewall Administrator’s Guide
Chapter 1
Introduction
This chapter provides an overview of the Barracuda Spam Firewall and includes the following topics:
Overview............................................................................................10
Barracuda Spam Firewall Models.....................................................13
Locating Information in this Document.............................................15
Introduction 9
Overview
The Barracuda Spam Firewall is an integrated hardware and software solution that provides powerful
and scalable spam and virus-blocking capabilities that do not impede the performance of your email
servers. The system has no per-user license fee and can be scaled to support tens of thousands of active
email users.
Using the Web-based administration interface, you can configure up to ten defense layers that protect
your users from spam and viruses. The ten defense layers are:
• Denial of service and security protection
• IP block list
• Rate control
• Virus check with archive decompression
• Proprietary virus check
• User-specified rules
• Spam fingerprint check
• Intention analysis
• Bayesian analysis
• Rule-based spam scoring
The following figure shows each of these defense layers in action:
Figure 1.1:
Energize Updates Minimize Administration and Maximize Protection
To provide you with maximum protection against the latest types of spam and virus attacks,
Barracuda Networks maintains a powerful operations center called Barracuda Central. From this
center, engineers monitor the Internet for trends in spam and virus attacks and post updated definitions
to Barracuda Central. These updates are then automatically retrieved by your Barracuda Spam
Firewall using the Energize Update feature.
By identifying spam trends at an early stage, the team at Barracuda Central can quickly develop new
and improved blocking techniques and virus definitions that are quickly made available to your
Barracuda Spam Firewall.
10 Barracuda Spam Firewall Administrator’s Guide
Description:Barracuda Spam Firewall is a trademark of Barracuda Networks Using the
Microsoft Outlook and Lotus Notes Plug-in Restoring from a Backup File .
