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Showing posts from January, 2021

How to protect your network against security flaws

  Redirector This is something you should only measure on your Terminal Server(s). You should monitor the "current commands" in the Redirector object. If the value is higher than 20 during sustained periods of time then you could have a bottleneck. Server Work Queues The Server Work Queues object should be monitored on the File server. You should monitor the "Available WorkItems" counter. Sustained values smaller than ten mean that the File server is running out of work items. When it does, performance really starts to plummet. Make sure this doesn't happen by upping the MinFreeworkItems value. Server In this object there's a counter called "Work Item Shortages". This value represents the number of times no work items were available or couldn't be allocated to service a file request. Obviously if you see any other value than zero, you need to start worrying. Upping the InitWorkItems or MaxWorkItems could help out here. Again, there's so muc...

Use the local security settings to force NTLMv2

  This policy setting determines which challenge or response authentication protocol is used for network logons. LAN Manager (LM) includes client computer and server software from Microsoft that allows users to link personal devices together on a single network. Network capabilities include transparent file and print sharing, user security features, and network administration tools. In Active Directory domains, the Kerberos protocol is the default authentication protocol. However, if the Kerberos protocol is not negotiated for some reason, Active Directory uses LM, NTLM, or NTLM version 2 (NTLMv2). LAN Manager authentication includes the LM, NTLM, and NTLMv2 variants, and it is the protocol that is used to authenticate all client devices running the Windows operating system when they perform the following operations: Join a domain Authenticate between Active Directory forests Authenticate to domains based on earlier versions of the Windows operating system Authenticate to computers...

A general approach to online network optimization problems

  Networking is ever present. Every business needs it from day one. Mobile devices and cloud services depend on it, and IoT devices are mission critical. Nearly every house or apartment has a router and devices communicating with the outside world. Given the proliferation of networked devices, people assume that networking is already a solved problem. But when your network starts behaving erratically, you realize networking is still difficult. Why? The flawed promise of public protocols A network with all its component parts purchased from the same company is extraordinarily uncommon. Modern networking enables hardware from different vendors to interoperate — in theory. There are several flaws in that vision. Public protocols are so flexible that people make hardware do things the writers never anticipated. The protocol definitions can have design flaws or errors in protocols and specifications. For instance, vendors implementing DNS make slightly different choices and those device...

Eight common obstacles encountered when networking

  Networking is ever present. Every business needs it from day one. Mobile devices and cloud services depend on it, and IoT devices are mission critical. Nearly every house or apartment has a router and devices communicating with the outside world. Given the proliferation of networked devices, people assume that networking is already a solved problem. But when your network starts behaving erratically, you realize networking is still difficult. Why? The flawed promise of public protocols A network with all its component parts purchased from the same company is extraordinarily uncommon. Modern networking enables hardware from different vendors to interoperate — in theory. There are several flaws in that vision. Public protocols are so flexible that people make hardware do things the writers never anticipated. The protocol definitions can have design flaws or errors in protocols and specifications. For instance, vendors implementing DNS make slightly different choices and those device...

6 Ways to Open the Task Manager in Windows

  Use the End Task feature to clean up unneeded apps and processes running in Task Manager on your Windows 8 computer. However, should proceed with caution. When forcing an app to close in this way, you lose any unsaved data. If you force an important system process to end, elements of your computer may stop working properly. Only close processes you've researched to ensure they're not essential to the running of your computer. Step 1 Press "Ctrl-Shift-Esc" to launch Task Manager. You can also open Task Manager by typing "Task" on the Start screen and then clicking "Task Manager" on the Apps list. Step 2 Click the "More Details" button in the bottom-left corner of Task Manager to display all of the program's tabs. Step 3 Select the application or process you want to close. Apps are listed under the Apps heading. Processes are listed under the Background Processes heading. Step 4 Click the "End Task" button in the bottom-righ...

How to check SMB version on Windows 10/8/7

  SMB or Server Message Block Protocols are used to connect your computer to an external server. Windows 10 ships with support of these protocols but they are disabled in the OOBE. Currently, Windows 10 supports SMBv1, SMBv2, and SMBv3 as well. Different servers depending upon their configuration require a different version of SMB to get connected to a computer. But in case you are using Windows 8.1 or Windows 7, you can check if you have it enabled too. That’s what we are going to do today. How to check SMB version on Windows 10/8/7 First of all, if you have Windows 7, you should not be disabling SMB v2. This is due to the following reasons: Request compounding – allows for sending multiple SMB 2 requests as a single network request Larger reads and writes – better use of faster networks Caching of folder and file properties – clients keep local copies of folders and files Durable handles – allow for connection to transparently reconnect to the server if there is a temporary disco...

Why networking is still difficult ?

  Networking is ever present. Every business needs it from day one. Mobile devices and cloud services depend on it, and IoT devices are mission critical. Nearly every house or apartment has a router and devices communicating with the outside world. Given the proliferation of networked devices, people assume that networking is already a solved problem. But when your network starts behaving erratically, you realize networking is still difficult. Why? The flawed promise of public protocols A network with all its component parts purchased from the same company is extraordinarily uncommon. Modern networking enables hardware from different vendors to interoperate — in theory. There are several flaws in that vision. Public protocols are so flexible that people make hardware do things the writers never anticipated. The protocol definitions can have design flaws or errors in protocols and specifications. For instance, vendors implementing DNS make slightly different choices and those device...

The flawed promise of public protocols

  Networking is ever present. Every business needs it from day one. Mobile devices and cloud services depend on it, and IoT devices are mission critical. Nearly every house or apartment has a router and devices communicating with the outside world. Given the proliferation of networked devices, people assume that networking is already a solved problem. But when your network starts behaving erratically, you realize networking is still difficult. Why? The flawed promise of public protocols A network with all its component parts purchased from the same company is extraordinarily uncommon. Modern networking enables hardware from different vendors to interoperate — in theory. There are several flaws in that vision. Public protocols are so flexible that people make hardware do things the writers never anticipated. The protocol definitions can have design flaws or errors in protocols and specifications. For instance, vendors implementing DNS make slightly different choices and those device...

What is Task Manager on a PC

  Use the End Task feature to clean up unneeded apps and processes running in Task Manager on your Windows 8 computer. However, should proceed with caution. When forcing an app to close in this way, you lose any unsaved data. If you force an important system process to end, elements of your computer may stop working properly. Only close processes you've researched to ensure they're not essential to the running of your computer. Step 1 Press "Ctrl-Shift-Esc" to launch Task Manager. You can also open Task Manager by typing "Task" on the Start screen and then clicking "Task Manager" on the Apps list. Step 2 Click the "More Details" button in the bottom-left corner of Task Manager to display all of the program's tabs. Step 3 Select the application or process you want to close. Apps are listed under the Apps heading. Processes are listed under the Background Processes heading. Step 4 Click the "End Task" button in the bottom-righ...

How to establish Parallel Computing

  The simultaneous growth in availability of big data and in the number of simultaneous users on the Internet places particular pressure on the need to carry out computing tasks “in parallel,” or simultaneously. Parallel and distributed computing occurs across many different topic areas in computer science, including algorithms, computer architecture, networks, operating systems, and software engineering. During the early 21st century there was explosive growth in multiprocessor design and other strategies for complex applications to run faster. Parallel and distributed computing builds on fundamental systems concepts, such as concurrency, mutual exclusion, consistency in state/memory manipulation, message-passing, and shared-memory models. Creating a multiprocessor from a number of single CPUs requires physical links and a mechanism for communication among the processors so that they may operate in parallel. Tightly coupled multiprocessors share memory and hence may communicate by...

network connections form loops and STP

  To build a loop-free topology, switches (bridges) determine the root bridge and compute the port roles. To do this, the bridges use special data frames called Bridge Protocol Data Units (BPDUs) that exchange bridge IDs and root path cost information. BPDUs are exchanged regularly, typically at two second intervals, and enable switches to keep track of network topology changes and to start and stop forwarding on ports as required. Hosts should not send BPDUs to the switch ports and to avoid malfunctioning/malicious hosts from doing so, the switch can filter or block BPDUs. If you enable BPDU filtering on a port, BPDUs received on that port are dropped but other network traffic is forwarded as usual.  If you enable BPDU blocking on a port, BPDUs received on that port are dropped and the port is shut down. Port Roles in RSTP Root Port (one per bridge): The forwarding port on each bridge which is on the best path to reach the root bridge. Designated Port: The forwarding port for...

Port States in Rapid Spanning Tree Protocol

  Rapid Spanning Tree Protocol (RSTP), a standard inter-switch protocol, ensures a loop-free forwarding network topology at Layer 2. This protocol was defined by the IEEE 802.1w standard and is an extension of the 802.1D Spanning Tree Protocol (STP). RSTP is an improvement over STP as it provides faster convergence after a network topology change or failure. RSTP introduces new port roles, and the original five port states of STP are reduced to three. To build a loop-free topology, switches (bridges) determine the root bridge and compute the port roles. To do this, the bridges use special data frames called Bridge Protocol Data Units (BPDUs) that exchange bridge IDs and root path cost information. BPDUs are exchanged regularly, typically at two second intervals, and enable switches to keep track of network topology changes and to start and stop forwarding on ports as required. Hosts should not send BPDUs to the switch ports and to avoid malfunctioning/malicious hosts from doing so,...

When Parallel Distributed Computing needful in networking

  The simultaneous growth in availability of big data and in the number of simultaneous users on the Internet places particular pressure on the need to carry out computing tasks “in parallel,” or simultaneously. Parallel and distributed computing occurs across many different topic areas in computer science, including algorithms, computer architecture, networks, operating systems, and software engineering. During the early 21st century there was explosive growth in multiprocessor design and other strategies for complex applications to run faster. Parallel and distributed computing builds on fundamental systems concepts, such as concurrency, mutual exclusion, consistency in state/memory manipulation, message-passing, and shared-memory models. Creating a multiprocessor from a number of single CPUs requires physical links and a mechanism for communication among the processors so that they may operate in parallel. Tightly coupled multiprocessors share memory and hence may communicate by...