Network Management Elective Reviewer PDF

# Chapter 8: Network Management In this final chapter, we provide a brief introduction into network management and firewalls. We begin by motivating the need to provide appropriate tools for the network administrator - the person whose job is to keep the network up and running. These tools are for...

# Chapter 8: Network Management In this final chapter, we provide a brief introduction into network management and firewalls. We begin by motivating the need to provide appropriate tools for the network administrator - the person whose job is to keep the network up and running. These tools are for monitoring, testing, polling, configuring, analyzing, evaluating, and controlling the operation of a network. We discuss the five key components of a network management architecture: - a network manager - a set of managed remote devices - management information bases (MIBs) - remote agents that report MIB information and take action under the control of the network manager - a protocol for communicating between the network manager and the remote devices We then delve into the details of the Internet Network Management Framework, and the SNMP protocol in particular. We also examine ASN.1 in some detail. We conclude this chapter with a discussion on firewalls - a topic that falls within the realms of both security and network management. We discuss how packet filtering and application-level gateways can be used to provide the network with some level of protection against unwanted intruders. ## 8.1: What Is Network Management? Having made our way through the first seven chapters of this text, we're now well aware that a network consists of many complex, interacting pieces of hardware and software - from the links, bridges, routers, hosts, and other devices that comprise the physical components of the network to the many protocols (in both hardware and software) that control and coordinate these devices. When hundreds or thousands of such components are cobbled together by an organization to form a network, it is not surprising that components will occasionally malfunction, that network elements will be misconfigured, that network resources will be overutilized, or that network components will simply "break" (for example, a cable will be cut, a can of soda will be spilled on top of a router). The network administrator, whose job it is to keep the network "up and running," must be able to respond to (and better yet, avoid) such mishaps. With potentially thousands of network components spread out over a wide area, the network administrator in a network operations center (NOC) clearly needs tools to help monitor, manage, and control the network. In this chapter, we'll examine the architecture, protocols, and information base used by a network administrator in this task. Before diving into network management itself, let's first consider a few illustrative "real-world" non-networking scenarios in which a complex system with many interacting components must be monitored, managed, and controlled by an administrator. Electrical power-generation plants (at least as portrayed in the popular media in such movies as the China Syndrome) have a control room where dials, gauges, and lights monitor the status (temperature, pressure, flow) of remote valves, pipes, vessels, and other plant components. These devices allow the operator to monitor the plant's many components, and may alert the operator (the famous flashing red warning light) when trouble is imminent. Actions are taken by the plant operator to control these components. Similarly, an airplane cockpit is instrumented to allow a pilot to monitor and control the many components that make up an airplane. In these two examples, the "administrator" monitors remote devices and analyzes their data to ensure that they are operational and operating within prescribed limits (for example, that a core meltdown of a nuclear power plant is not imminent, or that the plane is not about to run out of fuel), reactively controls the system by making adjustments in response to the changes within the system or its environment, and proactively manages the system (for example, by detecting trends or anomalous behavior, allowing action to be taken before serious problems arise). In a similar sense, the network administrator will actively monitor, manage, and control the system with which she/he is entrusted. In the early days of networking, when computer networks were research artifacts rather than a critical infrastructure used by millions of people a day, "network management" was an unheard of thing. If one encountered a network problem, one might run a few pings to locate the source of the problem and then modify system settings, reboot hardware or software, or call a remote colleague to do so. (A very readable discussion of the first major "crash" of the ARPAnet on October 27, 1980, long before network management tools were available, and the efforts taken to recover from and understand the crash is RFC 789). As the public Internet and private intranets have grown from small networks into a large global infrastructure, the need to more systematically manage the huge number of hardware and software components within these networks has grown more important as well. In order to motivate our study of network management, let's begin with a simple example. **Figure 8.1** illustrates a small network consisting of three routers, and a number of hosts and servers. **Figure 8.1** [Image description: A diagram of a small network with three routers labeled A, B, and C. Router B has a connection to an external network. Router A connects to two hosts. Router C connects to one host, labeled H1. There is a line, labeled "Link to external network", going from router B to a collection of dots that represent the external network.] Even in such a simple network, there are many scenarios in which a network administrator might benefit tremendously from having appropriate network management tools. - **Failure of an interface card at a host or a router.** With appropriate network management tools, a network entity (for example router A) may report to the network administrator that one of its interfaces has gone down. (This is certainly preferable to a phone call to the NOC from an irate user who says the network connection is down!) A network administrator who actively monitors and analyzes network traffic may be able to really impress the would-be irate user by detecting problems in the interface ahead of time and replacing the interface card before it fails. This might be done, for example, if the administrator noted an increase in checksum errors in frames being sent by the soon-to-die interface. - **Host monitoring.** Here, the network administrator might periodically check to see if all network hosts are up and operational. Once again, the network administrator may be able to really impress a network user by proactively responding to a problem (host down) before it is reported by a user. - **Monitoring traffic to aid in resource deployment.** A network administrator might monitor source-to-destination traffic patterns and notice, for example, that by switching servers between LAN segments, the amount of traffic that crosses multiple LANs could be significantly decreased. Imagine the happiness all around (especially in higher administration) when better performance is achieved with no new equipment costs. Similarly, by monitoring link utilization, a network administrator might determine that a LAN segment, or the external link to the outside world is overloaded and a higher-bandwidth link should thus be provisioned (alas, at an increased cost). The network administrator might also want to be notified automatically when congestion levels on a link exceed a given threshold value, in order to provision a higher-bandwidth link before congestion becomes serious. - **Detecting rapid changes in routing tables.** Route flapping--frequent changes in the routing tables--may indicate instabilities in the routing or a misconfigured router. Certainly, the network administrator who has improperly configured a router would prefer to discover the error his/herself, before the network goes down. - **Monitoring for SLAs.** With the advent of Service Level Agreements (SLA)--contracts that define specific performance metrics and acceptable levels of network provider performance with respect to these metrics--interest in traffic monitoring has increased significantly over the past few years [Larsen 1997; Huston 1999a]. UUnet and AT&T are just two of the many network providers that guarantee SLAs [UUNet 1999; AT&T SLA 1998] to their customers. These SLAs include service availability (outage), latency, throughput, and outage notification requirements. Clearly, if performance criteria are to be part of a service agreement between a network provider and its users, then measuring and managing performance will be of great importance to the network administrator. - **Intrusion detection.** A network administrator may want to be notified when network traffic arrives from, or is destined to, a suspicious source (for example, host or port number). Similarly, a network administrator may want to detect (and in many cases filter) the existence of certain types of traffic (for example, source-routed packets, or a large number of SYN packets directed to a given host) that are known to be characteristic of certain attacks. The International Organization for Standards (ISO) has created a network management model that is useful for placing the above anecdotal scenarios in a more structured framework. Five areas of network management are defined: - **Performance management.** The goal of performance management is to quantify, measure, report, analyze, and control the performance (for example, utilization, throughput) of different network components. These components include individual devices (for example, links, routers, and hosts) as well as end-to-end abstractions such as a path through the network. We will see shortly that protocol standards such as the Simple Network Management Protocol (SNMP) [RFC 2570] play a central role in Internet performance management. - **Fault management.** The goal of fault management is to log, detect, and respond to fault conditions in the network. The line between fault management and performance management is rather blurred. We can think of fault management as the immediate handling of transient network failures (for example, link, host, or router hardware or software outages), while performance management takes the longer term view of providing acceptable levels of performance in the face of varying traffic demands and occasional network device failures. As with performance management, the SNMP protocol plays a central role in fault management. - **Configuration management.** Configuration management allows a network manager to track which devices are on the managed network and the hardware and software configurations of these devices. - **Accounting management.** Accounting management allows the network manager to specify, log, and control user and device access to network resources. Usage quotas, usage-based charging, and the allocation of resource-access privileges all fall under accounting management. - **Security management.** The goal of security management is to control access to network resources according to some well-defined policy. The key distribution centers and certification authorities that we studied in Section 7.5 are components of security management. The use of firewalls to monitor and control external access points to one's network, a topic we will study in Section 8.4, is another crucial component. In this chapter, we'll cover only the rudiments of network management. Our focus will be purposefully narrow - we'll examine only the infrastructure for network management - the overall architecture, network management protocols, and information base through which a network administrator "keeps the network up and running." We'll not cover the decision-making processes of the network administrator, who must plan, analyze, and respond to the management information that is conveyed to the NOC. In this area, topics such as fault identification and management [Katzela 1995; Medhi 1997], proactive anomaly detection [Thottan 1998], alarm correlation [Jakobson 1993], and more come into consideration. Nor will we cover the broader topic of service management [Saydam 1996] - the provisioning of resources such as bandwidth, server capacity, and the other computational/communication resources needed to meet the mission-specific service requirements of an enterprise. In this latter area, standards such as TMN [Glitho 1995; Sidor 1998] and TINA [Hamada 1997] are larger, more encompassing (and arguably much more cumbersome) standards that address this larger issue. TINA, for example, is described as "a set of common goals, principles, and concepts that cover the management of services, resources, and parts of the Distributed Processing Environment" [Hamada 1997]. Clearly, all of these topics are enough for a separate text and would take us a bit far afield from the more technical aspects of computer networking. So, as noted above, our more modest goal here will be to cover the important "nuts and bolts" of the infrastructure through which the network administrator keeps the bits flowing smoothly. An often-asked question is "What is network management?". Our discussion above has motivated the need for, and illustrated a few of the uses of, network management. We'll conclude this section with a single-sentence (albeit a rather long, run-on sentence) definition of network management from [Saydam 1996]: "Network management includes the deployment, integration, and coordination of the hardware, software, and human elements to monitor, test, poll, configure, analyze, evaluate, and control the network and element resources to meet the real-time, operational performance, and Quality of Service requirements at a reasonable cost." It's a mouthful, but it's a good workable definition. In the following sections, we'll add some meat to this rather bare-bones definition of network management. ## 8.2: The Infrastructure for Network Management We've seen in the previous section that network management requires the ability to "monitor, test, poll, configure, . . . and control" the hardware and software and components in a network. Because the network devices are distributed, this will minimally require that the network administrator be able to gather data (for example, for monitoring purposes) from a remote entity and be able to affect changes (for example, control) at that remote entity. A human analogy will prove useful here for understanding the infrastructure needed for network management. Imagine that you're the head of a large organization that has branch offices around the world. It's your job to make sure that the pieces of your organization are operating smoothly. How would you do so? At a minimum, you'll periodically gather data from your branch offices in the form of reports and various quantitative measures of activity, productivity, and budget. You'll occasionally (but not always) be explicitly notified when there's a problem in one of the branch offices; the branch manager who wants to climb the corporate ladder (perhaps to get your job) may send you unsolicited reports indicating how smoothly things are running at his/her branch. You'll sift through the reports you receive, hoping to find smooth operations everywhere, but no doubt finding problems in need of your attention. You might initiate a one-on-one dialogue with one of your problem branch offices, gather more data in order to understand the problem, and then pass down an executive order ("Make this change!") to the branch office manager. Implicit in this very common human scenario is an infrastructure for controlling the organization - the boss (you), the remote sites being controlled (the branch offices), your remote agents (the branch office managers), communication protocols (for transmitting standard reports and data, and for one-on-one dialogues), and data (the report contents and the quantitative measures of activity, productivity, and budget). Each of these components in human organizational management has a counterpart in network management. The architecture of a network management system is conceptually identical to this simple human organizational analogy. The network management field has its own specific terminology for the various components of a network management architecture, and so we adopt that terminology here. As shown in Figure 8.2, there are three principle components of a network management architecture: a managing entity (the boss in our above analogy - you), the managed devices (the branch office), and a network management protocol. **Figure 8.2** [Image description: A diagram of the components of a network management architecture. The diagram contains three boxes, connected by arrows. One box is labeled "Managing entity." The other two boxes are labeled "Managed device," with "Agent" boxed inside each. Arrows point from "Managing entity" to each "Managed device." The arrow from "Managing entity" to the first "Managed device" is labeled "data" and the arrow from "Managing entity" to the second "Managed device" is labeled "data", with an "x" over the arrow. Arrows point from "Agent" to the "Managed device" labeled "data." A box labeled "Network management protocol" is found below the managing entity, with arrows facing up toward the managing entity.] The managing entity is an application, typically with a human in the loop, running in a centralized network management station in the network operations center (NOC). The managing entity is the locus of activity for network management; it controls the collection, processing, analysis, and/or display of network management information. It is here that actions are initiated to control network behavior and here that the human network administrator interacts with the network devices. A managed device is a piece of network equipment (including its software) that resides on a managed network. This is the branch office in our human analogy. A managed device might be a host, router, bridge, hub, printer, or modem device. Within a managed device, there may be several so-called managed objects. These managed objects are the actual pieces of hardware within the managed device (for example, a network interface card), and the sets of configuration parameters for the pieces of hardware and software (for example, an intradomain routing protocol such as RIP). In our human analogy, the managed objects might be the departments within the branch office. These managed objects have pieces of information associated with them that are collected into a management information base (MIB); we'll see that the values of these pieces of information are available to (and in many cases able to be set by) the managing entity. In our human analogy, the MIB corresponds to quantitative data (measures of activity, productivity, and budget, with the latter being setable by the managing entity!) exchanged between the branch office and the main office. We'll study MIBs in detail in Section 8.3. Finally, also resident in each managed device is a network management agent, a process running in the managed device that communicates with the managing entity, taking local actions on the managed device under the command and control of the managing entity. The network management agent is the branch manager in our human analogy. The third piece of a network management architecture is the network management protocol. The protocol runs between the managing entity and the managed devices, allowing the managing entity to query the status of managed devices and indirectly take actions at these devices via its agents. Agents can use the network management protocol to inform the managing entity of exceptional events (for example, component failures or violation of performance thresholds). It's important to note that the network management protocol does not itself manage the network. Instead, it provides a tool with which the network administrator can manage ("monitor, test, poll, configure, analyze, evaluate and control") the network. This is a subtle, but important distinction. Although the infrastructure for network management is conceptually simple, one can often get bogged down with the network-management-speak vocabulary of "managing entity," "managed device," "managing agent," and "management information base." For example, in network-management-speak, our simple host monitoring scenario, "managing agents" located at "managed devices" are periodically queried by the "managing entity" - a simple idea, but a linguistic mouthful! Hopefully, keeping the human organizational analogy and its obvious parallels with network management in mind will be of help as we continue through this chapter. Our discussion of network management architecture above has been generic, and broadly applies to a number of the network-management standards and efforts that have been proposed over the years. Network-management standards began maturing in the late 1980s, with OSI CMISE/CMIP (the Common Management Service Element/Common Management Information Protocol) [Piscatello 1993; Stallings 1993; Glitho 1998] and the Internet SNMP (Simple Network-Management Protocol) [Stallings 1993; RFC 2570, Stallings 1999; Rose 1996] emerging as the two most important standards [Miller 1997; Subramanian 2000]. Both are designed to be independent of vendor-specific products or networks. Because SNMP was quickly designed and deployed at a time when the need for network management was becoming painfully clear, SNMP found widespread use and acceptance. Today, SNMP has emerged as the most widely used and deployed network management framework. We cover SNMP in detail in the following section. # 6.1. Simple Network Management Protocol (SNMP) SNMP _is_ an Internet Standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior. SNMP stands for Simple Network Management Protocol and consists of three key components: managed devices, agents, and network-management systems (NMSs). The protocol is a set of standards for communication with devices in a TCP/IP network. SNMP monitoring is useful for anyone who is responsible for servers and network devices such as hosts, routers, hubs, and switches. It lets you keep an eye on network and bandwidth usage and track important issues such as uptime and traffic levels (Paessler, 2020). ## Simple Network Management Protocol (SNMP) SNMP is a widely used protocol, you can find it in network management for network monitoring. With this protocol you can manage and monitor network elements (routers, switches, printers, IP telephones etc.), collect information about them. It's a part of the TCP/IP protocol suite. ## SNMP overview SNMP works like a client-server. It consists of 4 elements (SNMP Manager/monitoring server, Managed devices, SMNP Agent, MIB), with these elements, it's possible to achieve a fully functional SNMP network. - **Agent** is a network element, a software which runs on the managed device. It stores and retrieves information about the device. It can also signal an event to the manager if something happens (printer's toner runs out of tint for example). - **Manager** is the key element in SMNP, it's responsible to communicate with the agent(s). You can query an agent to get information about a managed device, for example a status information. You can also change settings in the managed device sending a 'set' command to the agent. The software, which is called _NMS_ (Network Management System), runs on the manager. - **Managed devices** are part of the network, that requires management and monitoring: printers, routers, switches and so on. They report to the manager via SNMP, using agent software component. - **Management Information database**, in sort _MIB_. Every agent describing the managed device parameters, using this _MIB_ database. These _MIBs_ have a set of unique addresses, _OIDs_, using these _OIDs_ (for example: 1.3.6.1.2.1.1.1.0), you can query different kind of information about the device. **Figure 1 - SNMP network: Monitoring server with large variety of devices** [Image description: A diagram of an SNMP network. The top center of the diagram contains a rectangle labeled "Monitoring Server." Five rectangles are found pointing toward the "Monitoring Server," labeled: "SNMP," "SNMP," "SNMP," "SNMP," and "SNMP." The rectangles below the "Monitoring Server" are labeled: "SNMP," "SNMP," "SNMP," and "SNMP." A fire icon appears below the "Monitoring Server" with an arrow pointing down. A Penguin icon is below the first "SNMP," with an arrow pointing up. A Windows icon is below the second "SNMP," with an arrow pointing up. A box with the windows logo appears below the third "SNMP," with an arrow pointing up. A monitor icon is below the fourth "SNMP," with an arrow pointing up. A black box is below the fifth "SNMP," with an arrow pointing up. A small computer icon is below the first "SNMP," with an arrow pointing up. An unlabeled box appears with an arrow pointing up below the second "SNMP." An unlabeled box appears below the third "SNMP," with an arrow pointing up. A box with a question mark is below the last "SNMP," with an arrow pointing up] ## How you can use SNMP with SMS service? There are different ways to implement SMS service to your SNMP network. You can use SMS messages to create signals (in SNMP we call these 'traps') to alert the manager if something happens (toner runs out). This can be useful when a device does not support SNMP, but you want to implement it somehow to a SNMP compatible network. You can use the monitoring server to query information and if the received information matches a condition, you can also send a SMS with custom text to a person, or group of people. Another example is, when the manager gets a specified trap from a device, then you can alert a person using SMS to notify her/him. ## SNMP protocol in Ozeki At first you need to login to Ozeki 10 with your username and password. **Figure 2.1. - Logging in to Ozeki 10** [Image description: A screenshot of the Ozeki 10 login screen. The screen has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/?a=Login" in grey text. The body of the screen is light blue. In the center of the screen is a white box with a blue header that says "OZEKI 10" in white text. The text "Login" appears below the centered header text. The text "admin" is in the field that appears below the word "Login," and a row of dots is in the password field, below the user field. Below the password and user fields is a blue button labeled "OK." Below the "OK" button is a grey box with the following text: "OZEKI http://192.168.112.175:9505 Version: 10.1.8 © 2000-2018 Ozeki Ltd (www.ozeki.hu)" ] After, you have logged in, select 'Control Panel'. **Figure 2.2. - Selecting 'Control Panel'** [Image description: A screenshot of the Ozeki 10 Control Panel screen. The screen has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/?a=Desktop" in grey text. The body of the screen is light blue. A white box with a blue header that says "Control Panel" in white text is found near the top of the screen. Below this box is a series of rectangular icons, each with a caption, in blue and white text: "Recycle Bin", "Control Panel", "File Manager", and "Serial ports". Below this set of icons is a row of icons, each with a caption in blue and white text: "SMS Gateway," "Start," and "Control Panel." A larger white box with a text field labeled "Search...," a bar to the right with a question mark icon, and a button with a folder icon is found near the top right of the screen. The time "11:49" is shown at the bottom right of the screen. ] In Ozeki there are 4 different ways to use this protocol effectively: 1. **SNMP agent - initiates SNMP trap if SMS is received:** In this option you can configure an agent, when this agent gets a SMS message it will forward to the monitoring server as a trap. You can also specify the parameters for the SNMP trap service. (Figure 2.3) **Figure 2.3. - SNMP agent - initiates SNMP trap if SMS is received** [Image description: A diagram of the SNMP protocol, with one arrow pointing between "SMS" and "SNMP agent," and another arrow pointing between "SNMP agent" and "Monitoring Server." ] ## How to add this connection in Ozeki 10? Click on the blue 'Create new Connection' button. **Figure 3. - Clicking 'Create new Connection' ** [Image description: A screenshot of the Ozeki 10 Control Panel with the "Create new Connection" button highlighted. The background has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/Control+Panel/?a=Home" in grey text. The body of the screen has light blue background. A white box with a blue header that says "Control Panel - 192.168.112.175" in white text appears at the top. Below this is a set of icons with captions: "Home," "Users," "Connections," "Events," and "System." A blue box labeled "Settings" is found to the right of the icons. Another blue box labeled "Help" is found to the right of the settings box. A smaller white box appears near the top right of the screen, with a blue header that says "admin@localhost" and a "Type" button labeled "Admin?" and a "Details" button. A blue box labeled "Search" appears to the right of the box. A row of icons appears below labeled "Connections," "Routes," "Serial Ports," "Start," and "Control Panel". An Ozeki logo appears at the top right corner and text beneath it says "OZEKI www.ozeki.hu." The text 15:50 appears at the bottom right of the screen.] From the connection methods, select 'Application'. **Figure 4. - Selecting 'Application'** [Image description: A screenshot of the Ozeki 10 Control Panel window with the "Application" selection highlighted. The background has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/Control+Panel/?a=Home" in grey text. The body of the screen has light blue background. A white box with a blue header that says "Control Panel - 192.168.112.175" in white text appears at the top. Below this is a set of icons with captions: "Home," "Users," "Connections," "Events," and "System." A blue box labeled "Settings" is found to the right of the icons. Another blue box labeled "Help" is found to the right of the settings box. All icons, and the "Settings" and "Help" boxes are highlighted in light grey. A smaller white box appears near the top right of the screen, with a blue header that says "admin@localhost" and a "Type" button labeled "Admin?" and a "Details" button. A blue box labeled "Search" appears to the right of the box. A row of icons appears below labeled "Connections," "Routes," "Serial Ports," "Start," and "Control Panel." An Ozeki logo appears at the top right corner and text beneath it says "OZEKI www.ozeki.hu." The text 15:53 appears at the bottom right of the screen.] From the SNMP connections, select 'SNMP trap'. **Figure 5. - Finally, clicking on 'SNMP trap' ** [Image description: A screenshot of the Ozeki 10 Control Panel with the "SNMP trap" selection highlighted. The background has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/Control+Panel/?a=Home" in grey text. The body of the screen has light blue background. A white box with a blue header that says "Control Panel - 192.168.112.175" in white text appears at the top. Below this is a set of icons with captions: "Home," "Users," "Connections," "Events," and "System." A blue box labeled "Settings" is found to the right of the icons. Another blue box labeled "Help" is found to the right of the settings box. All icons, and the "Settings" and "Help" boxes are highlighted in light grey. A smaller white box appears near the top right of the screen, with a blue header that says "admin@localhost" and a "Type" button labeled "Admin?" and a "Details" button. A blue box labeled "Search" appears to the right of the box. A row of icons appears below labeled "Connections," "Routes," "Serial Ports," "Start," and "Control Panel." An Ozeki logo appears at the top right corner and text beneath it says "OZEKI www.ozeki.hu." The text 15:54 appears at the bottom right of the screen.] After you have tweaked the settings, click 'Ok', to start the service with the desired settings. **Figure 6. - Available settings** [Image description: A screenshot of a form from the Ozeki 10 Control Panel , with text inputs labeled "Connection name", "SNMP agent host", "SNMP agent port", "SNMP protocol version", "Generic Trap Code", "Specific Trap Code", "Community name." The text inputs labeled "Sender address" and "Overridable" are found below these inputs. These inputs are highlighted in grey. The form also has a set of buttons labeled "Back," "Ok," and "Cancel." The form has a blue header labeled "Connection details," and a button labeled "Advanced" is found above the "Back" button. To the right of the form, a second form also has a blue header labeled "Connection details", and a button labeled "Advanced" is found above the "Back" button, and another form is shown to the right of the first, also with a blue header and "Advanced" button, with a set of buttons labeled "Back," "Ok," and "Cancel"] 2. **SNMP agent - accepts SNMP query, and forwards it as SMS:** The next option is, when somebody would like to get some information about an SNMP supported device, then a query, 'get request' is to be sent to the agent. In this case an SMS will be sent to the specified number to notify a person about that somebody queried the agent, device (Figure 3). **Figure 3.1 - SNMP agent - accepts SNMP query, and forwards it as SMS ** [Image description: A diagram of the SNMP protocol, with one arrow pointing between "Monitoring Server" and "SNMP agent," and another arrow pointing between "SNMP agent" and "SMS." ] ## How to add this connection in Ozeki 10? Click on the blue 'Create new Connection' button. **Figure 3.4 - Clicking 'Create new Connection' ** [Image description: A screenshot of the Ozeki 10 Control Panel with the "Create new Connection" button highlighted. The background has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/Control+Panel/?a=Home" in grey text. The body of the screen has light blue background. A white box with a blue header that says "Control Panel - 192.168.112.175" in white text appears at the top. Below this is a set of icons with captions: "Home," "Users," "Connections," "Events," and "System." A blue box labeled "Settings" is found to the right of the icons. Another blue box labeled "Help" is found to the right of the settings box. A smaller white box appears near the top right of the screen, with a blue header that says "admin@localhost" and a "Type" button labeled "Admin?" and a "Details" button. A blue box labeled "Search" appears to the right of the box. A row of icons appears below labeled "Connections," "Routes," "Serial Ports," "Start," and "Control Panel." An Ozeki logo appears at the top right corner and text beneath it says "OZEKI www.ozeki.hu." The text 15:50 appears at the bottom right of the screen.] From the connection methods, select 'Application'. **Figure 4. - Selecting 'Application'** [Image description: A screenshot of the Ozeki 10 Control Panel window with the "Application" selection highlighted. The background has a white background with a blue and white header that says "OZEKI 10 (192.168.112.175)" in blue and white text, and a button labeled "localhost:9505/Control+Panel/?a=Home" in grey text. The body of the screen has light blue background. A white box with a blue header that says "Control Panel - 192.168.112.175" in white text appears at the top. Below this is a set of icons with captions: "Home," "Users," "Connections," "Events," and "System." A blue box labeled "Settings" is found to the right of the icons. Another blue box labeled "Help" is found to the right of the settings box. All icons, and the "Settings" and "Help" boxes are highlighted in light grey. A smaller white box appears near the top right of the screen, with a blue header that says "admin@localhost" and a "Type" button labeled "Admin?" and a "Details" button. A blue box labeled "Search" appears to the right of the box. A row of icons appears below labeled "Connections," "Routes," "Serial Ports," "Start," and "Control Panel." An Ozeki logo appears at the top right corner and text beneath