The granddaddy of packet-sniffing tools

Sniffer Portable Analysis Suite 3.5, from Sniffer Technologies, a Network Associates business, is a Windows-based fault analysis and performance management toolkit for network support staff in large organizations. The suite provides a complete set of network analysis tools, including Sniffer Pro LAN, Sniffer Pro WAN, and Sniffer Pro High Speed. Each product supports a different set of network interfaces. Together, the programs include support for Ethernet, Gigabit Ethernet, asynchronous transfer mode (ATM), and WAN links and can decode a variety of protocols. Organizations that have 10/100 Ethernet and Token-Ring networks might consider Sniffer Basic, which is a more affordable package. However, Sniffer Basic doesn't include Sniffer Technologies' Expert analysis feature, which diagnoses network performance problems. Sniffer Technologies included Sniffer Reporter 3.5 with my review package; Sniffer Reporter is available at extra cost and adds graphical reporting capabilities for 10/100 Ethernet and Token-Ring data.

Installing the Sniffer Portable Analysis Suite is simple. I launched setup.exe, confirmed the default installation directory, and rebooted the system. When you install Sniffer, the program detects network cards installed on the system and lets you select a card to monitor network traffic. The suite will work with any network card that you can place in promiscuous mode. However, if you want to fully support the suite's features, you need to use a network card that Network Associates supports with an enhanced driver. In addition, Gigabit Ethernet support requires that you run the software on a Dolch PAC 64 or Dolch PAC 65 portable computer.

The suite's documentation includes an Installation Guide, a Getting Started Guide, and online Help. The documentation materials are clear and useful for beginning users. However, I wanted more details about how to implement features and create and use filters and triggers, and about how the software evaluates filter criteria (e.g., which elements are ANDs, which are ORs, and what precedent order exists when the software evaluates an expression). More detailed information might save network analysts hours of experimentation. The installation guide refers users to several other manuals that can help you use Portable Analysis Suite with additional hardware components, including the Switch Expert Connection and Configuration Guide and manuals for ATM, WAN, and a Fast Ethernet full-duplex pod.

Monitor Mode
Sniffer has two primary operating modes: Monitor mode and Capture mode. When you start Sniffer, the program enters the default Monitor mode and displays the Dashboard Monitor application and an inactive Capture dashboard. The program includes several monitoring applications, each of which gives you a different view of your network's traffic. The statistics that each monitoring application provides depend on which physical interface you monitor. LAN adapters, ATM adapters, and WAN adapters will each provide a different set of metrics.

Screen 1 shows example displays from the Matrix, Protocol Distribution, and Host Table monitor applications. You can use display filters to limit the information that these monitor applications display. You can use a variety of criteria—including network address, network protocol, and packet contents—to include or discard packets. Monitor filters let you prioritize your problems and avoid wasting time reviewing network packets that don't relate to problems you're working on.

Monitor Applications
Before you create a performance management program, you need to know what performance is normal for your application. Therefore, I began testing by examining the History Samples monitor application, which you can use to easily collect baseline statistics. The application collects as many as 10 samples simultaneously and lets you choose from a variety of network metrics. You can include basic metrics (such as packets per second, segment utilization, error rates) and specific metrics (such as the occurrence rates of specific error types—e.g., runts and collisions—and the occurrence rates of packets in a particular size range). For each sample you collect, you specify sampling frequency and upper and lower sample thresholds. Sniffer will record as many as 3600 points for each sample before data collection automatically turns off. You can export baseline samples to other applications in comma-separated, tab-delimited, or fixed-format text files.

Using the History Samples application is easy. An icon for each metric that you can sample appears in the application interface. To sample a metric, you simply click the appropriate icon. I right-clicked in the History Samples window, selected New Multiple Sample from the context menu, and created a 10-metric sample after clicking an icon to start sampling. When sampling starts, the application displays data graphically and gives you the option to save the data when you close the window.

After you establish baseline information, you can use the Host Table Monitor application to display realtime statistics for each network node that has traffic visible to Sniffer. When I started the application, it quickly displayed a list of network nodes that grew as the application detected network traffic from additional systems. To display overall traffic statistics for a network node, you select Outline view; to break down node traffic by protocol type, you select Detail view. You can also display summary views for either IP traffic or IPX-only traffic. Other toolbar icons display Top Talkers (network nodes that generate the most traffic) in either bar- or pie-chart format. Another context menu item lets you display data in tables so that you can export the data to other applications. You can select a column heading to sort table data, which lets you quickly see which network node is generating the most activity.

To use the Host Table Monitor application, I selected a network node, then clicked Capture to capture packets going to and from that node. The standard Expert display (which I describe shortly) appeared. When I selected Stop and Display from the Capture menu, additional tabs appeared, giving me several views of the captured data. The application let me save the captured packets to a capture file to review later.

Next, I tested the Matrix Monitor application. To access this application, I selected Matrix monitor from the Monitor menu. Like the Host Table Monitor application, the Matrix Monitor application displays realtime statistics for each pair of network nodes that are in communication. The Matrix Monitor application offers several views of paired-node traffic statistics. The Map view graphically represents the node pairs, the Outline view shows packet and byte counts in a tabular format, and the Detail view breaks down the conversation pairs by protocol. You can also display a Top Talkers chart. You can export the table view and capture highlighted node-pair packets within the Matrix Monitor application. I appreciated having the ability to limit the display to the IP or IPX protocols and to select any column heading in a tabular display to sort columns.

After I reviewed the Matrix Monitor application's features, I used the Protocol Distribution Monitor application to quickly view the protocols that the monitored network segment was using and each protocol's relative volumes of network traffic on the segment. In addition to the network protocols that Sniffer recognizes, the Protocol Distribution Monitor IP and IPX tabs provide traffic statistics for common IP (port level) applications and for IPX protocols such as SPX, Service Advertising Protocol (SAP), and NetBIOS. I selected Pause to freeze the screen, then selected Export to save a Protocol Distribution data sample. The application let me save the data as a space-delimited, tab-delimited, or comma-delimited file to use with a database, spreadsheet, or other reporting application.

The Dashboard Monitor application, which features three dashboard-style dials, is the default application that displayed when I started Sniffer. This application displays overall network activity, including Packets per Second, Segment Utilization Percentage, and Errors per Second. In this application, the Detail view displays a running total for all available metrics, and the Export function saves the running total for all metrics to one of the three file formats that Sniffer supports.

Sniffer Technologies' documentation also describes the Global Statistics Monitor application (which breaks down network traffic by packet size and bandwidth utilization and displays the data in either a bar or pie chart) and several other monitor applications that are relevant to only a few hardware environments. The Smart Screens application displays counters for ATM cell and frame types. The Physical Layer Statistics window, relevant only to ATM networks, displays various metrics, depending on the transmission media and connection type. The Switch Statistics window is available when Sniffer is connected to a Cisco Catalyst 5000 switch and displays statistics for the physical port module or Virtual LAN (VLAN) that you define in the switch. I hope Network Associates extends support for other switches in future versions of Sniffer.

Sniffer maintains an Alarm Log for events that the Sniffer Expert, the Dashboard Monitor application, and the Switch Statistics application detect. The Dashboard adds events to the Sniffer Alarm Log whenever one of the available metrics exceeds a threshold value that you enter on the Threshold tab on the Dashboard Properties page. The Sniffer Expert records alarms for symptoms that the software detects and diagnoses it makes. You can set each alarm to one of five severity levels. You can configure as many as four Notification Actions for each severity level. These actions can sound an audible alarm, use an available SMTP server to send an email message, call a pager, or run a VBScript routine. You can enable and disable alarms according to a weekly schedule so you won't be disturbed at noncrucial times.

Capture Mode
Capture Mode complements Monitor Mode by capturing full or partial network packets to a capture buffer file. Capture Mode includes Sniffer's realtime Expert analysis feature, which detects symptoms of network problems and diagnoses underlying problems. When capturing is active, only the Expert analysis summary view of the captured packets is available. After you stop and display data that Sniffer captures, you can view individual packets in the Decode window. Matrix, Host Table, and Protocol Distribution views are also available; these views display summaries of data that are similar to those that the corresponding Monitor application creates.

Capture mode includes two powerful features: filters and triggers. Capture filters let you ignore packets that you can't use and highlight the packets that you want. Capture filters screen packets either according to simple address or protocol criteria or according to complex Boolean expressions that examine packet parts that you define. A trigger automatically starts a capture session when the program recognizes a predefined criterion (e.g., time of day, an alarm, packet characteristics). You can set packet capture to continue for a specific period of time or to stop at a specific time of day or when the program recognizes a second criterion.

When, after a network reconfiguration, the connection between my remote mail server and one of my workstations failed, I created a filter that would capture all traffic to and from the workstation and ignore other traffic on the network. I used this filter to define both the start criteria and capture criteria for a trigger. I didn't define stop criteria, which meant I could stop the capture manually when I was ready to look at the captured data. I selected OK on the Trigger Setup screen to activate the trigger (you can activate only one trigger at a time). Then, I started my mail client at the workstation. The resulting network traffic started the capture. After I reproduced the failure, I stopped and displayed the data I'd captured. The data revealed that, after trying to connect using the mail server's NetBIOS name, Microsoft Outlook appended the default IP domain name and attempted to connect again. The connection failed again. I used the remote mail server's proper DNS name in the mail client to correct the problem and speedily reestablished the connection.

Expert analysis. When you select Start from the Capture menu, the Expert window appears. This window lets you view Sniffer's summary and analysis of the packet stream the software is capturing. A selection pane at the left side of the window lets you select Objects, Symptoms, or Diagnoses to display in the right-hand pane. Objects reveal the activity of Network Nodes at different network layers. Symptoms are alerts that Sniffer generates when a metric passes a predefined threshold. Diagnoses are Sniffer's assessment of the underlying problem that one or more Symptoms indicates.

The right pane also lets you display more detailed network activity information sorted by network layer. Sniffer provides Application, Session, Connection, Station, and Data Link Control (DLC) layer information. After Sniffer monitored part of the Lab network for a few minutes, I displayed Objects. Sniffer reported several kinds of activity: several Server Message Block (SMB) conversations at the Application layer; WINS, IP, NetBIOS, and NETBEUI conversations at the Session layer; TCP and UDP traffic at the Connection layer; packet counts by protocol at the Station layer; and Ethernet frames by vendor-translated media access control (MAC) address at the DLC layer. A Global layer shows summary statistics. A Route layer decodes and displays route information from Routing Information Protocol (RIP) packets. A Subnet layer displays information about network subnet addresses that the program detects.

When I selected Symptoms to display during my test, the right pane showed symptom reports at the Application, Connection, and Station layers. The Application symptoms were reports of systems that aren't in the Domain list. The Connection symptoms were all related to timing. The only Station Symptom that Sniffer reported was Time-to-live exceeded in transit. All these symptoms are minor, and Sniffer reported no Diagnoses for these symptoms.

The Expert analysis feature promises to reduce the technical skill levels that network support technicians need to use Sniffer. Although I can't measure how useful the Expert analysis feature will be for a specific organization, any tool that aids identification and interpretation of network symptoms will be helpful to all but the most experienced network analysts.

Post-capture analysis. When you stop and display captured data or load a capture file that you've saved, the Expert window renames itself as a Sniffer window, and several tabs appear at the bottom of the pane. Screen 2, page 146, shows an example of a post-capture window. From the Expert tab, you can see how many Diagnoses, Symptoms, and Objects exist at each protocol layer. If you highlight a protocol layer, the number of packets of each protocol type will display in the lower left corner of the pane. The Objects tab (which is to the right of the Expert-tab view) gives details about each highlighted object. The Statistics tab displays summary information for a capture session and includes packet and byte counts (both total and organized by protocol), average network utilization, and broadcast traffic statistics. The Host Table, Matrix, and Protocol Dist. tabs provide information similar to the information that the Monitor application provides. The Decode tab is the entry point for packet protocol decode displays, which will be familiar to anyone who has used Windows NT Network Monitor or other packet-sniffing programs.

The Decode window has three stacked panes: The upper pane lists a one-line summary of each frame, the middle pane displays decoded data, and the bottom pane displays captured frames in hexadecimal notation. Sniffer also saves Status and Expert records with the capture. Sniffer's post-capture tools let you set packet display filters, select a set of specific frames for display, and search for frames containing text or data you specify.

Additional Sniffer Features
You can save the names and addresses of network nodes you discover during monitoring and capturing in the Sniffer Address Book. You can access this network address information by node name. Sniffer includes a set of IP network tools, including Ping, Trace Route, DNS Lookup, Finger, and Whois. Sniffer also lets you configure operations to suit your needs. For example, you can choose to display or suppress specific protocols, set the color Sniffer uses to display a protocol, and set IP port names.

Overall, the Portable Analysis Suite's user interface (UI) is easy to understand and use. The address book, which lets network device names display in place of network addresses on various displays, is easy to create when you use the Display Discovered Addresses menu item and the Update Address Book option. After you create a Sniffer address book, Sniffer's other displays are more user-friendly because they display a computer's name instead of its address.

Sniffer Technologies can improve a few aspects of the suite's usability. For example, when you define filters, Sniffer maintains separate sets for Display filters and Capture filters. The only difference between the two filters is the presence of buffer-related parameters (which have default values) in the Capture filter. Sniffer Technologies might simplify the program by letting users use one set of filter definitions as either Display or Capture filters. You can set up another common filter criterion—TCP or UDP port numbers—by selecting one of a predefined number of ports. However, if the port you want isn't on the list, your only option is to create a custom data pattern and compare specific offsets within the packet with specific hex values. This task requires both technical knowledge and impeccable typing skills. However, a handy shortcut for creating Data Pattern filters exists. When you view a packet on Capture's Decode tab, you can select Define Filter from the Capture menu and select portions of the packet to easily create a custom data pattern, as Screen 3 shows. Using a TCP or UDP port number as a filter criterion is common, and I'm surprised that a simple way to key in port numbers directly doesn't exist. You must also use a data pattern to construct other common filtering criteria. Although capturing data to and from specific systems is easy, filtering to capture all traffic to or from all stations on an IP subnet requires data-pattern filtering. An ability to filter on a network address and subnet mask would be useful. Changing Boolean logic in a data pattern is a cumbersome process that requires deleting and adding lines. A drag-and-drop feature would simplify these steps. The UI for defining filters is easy to use for simple filters, but the interface is cumbersome when you need to use Boolean logic or an undefined port.

Support for additional switches would also enhance this software. Although I wasn't able to test this feature, the ability to connect to a Cisco 5000 switch and monitor a specific VLAN is important, especially because fully switched networks have become standard. Sniffer Technologies plans to add support for additional switches in version 4.0.

Sniffer Portable Analysis Suite is a feature-rich network monitoring and protocol-analysis application that will attract enterprises that need to support a broad range of LANs or large WANs. Sniffer Basic will be attractive to small organizations that need a more sophisticated network monitoring tool than Microsoft Systems Management Server (SMS) Network Monitor. The suite is valuable both for routine network monitoring and for troubleshooting specific network problems.

Sniffer Portable Analysis Suite 3.5
Sniffer Technologies, a Network Associates business * 800-764-3337
http://www.sniffer.com
Price: $15,995 for a 1-year subscription; $19,995 for a 2-year subscription; $29,995 for a perpetual license (excluding updates, KnowledgeCenter, and technical support). Contact vendor for purchase price. Separate pricing for individual products.
Decision Summary:
Pros: Easy to use; provides realtime alerts and sophisticated protocol decoding; Expert analysis component logs symptoms of network errors and diagnoses problems; supports a broad range of LANs and WANs
Cons: Pricing for high-speed network support won't appeal to small organizations; the suite is most effective for administrators who are skilled in network monitoring and analysis; the user interface for defining Capture and Display filters is cumbersome; Capture mode allows only one active trigger at a time