An Internet Protocol (IP) Address Is a Numerical Label That Is
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Virtual Memory
Chapter 4 Virtual Memory Linux processes execute in a virtual environment that makes it appear as if each process had the entire address space of the CPU available to itself. This virtual address space extends from address 0 all the way to the maximum address. On a 32-bit platform, such as IA-32, the maximum address is 232 − 1or0xffffffff. On a 64-bit platform, such as IA-64, this is 264 − 1or0xffffffffffffffff. While it is obviously convenient for a process to be able to access such a huge ad- dress space, there are really three distinct, but equally important, reasons for using virtual memory. 1. Resource virtualization. On a system with virtual memory, a process does not have to concern itself with the details of how much physical memory is available or which physical memory locations are already in use by some other process. In other words, virtual memory takes a limited physical resource (physical memory) and turns it into an infinite, or at least an abundant, resource (virtual memory). 2. Information isolation. Because each process runs in its own address space, it is not possible for one process to read data that belongs to another process. This improves security because it reduces the risk of one process being able to spy on another pro- cess and, e.g., steal a password. 3. Fault isolation. Processes with their own virtual address spaces cannot overwrite each other’s memory. This greatly reduces the risk of a failure in one process trig- gering a failure in another process. That is, when a process crashes, the problem is generally limited to that process alone and does not cause the entire machine to go down. -
How to Find out the IP Address of an Omron
Communications Middleware/Network Browser How to find an Omron Controller’s IP address Valin Corporation | www.valin.com Overview • Many Omron PLC’s have Ethernet ports or Ethernet port options • The IP address for a PLC is usually changed by the programmer • Most customers do not mark the controller with IP address (label etc.) • Very difficult to communicate to the PLC over Ethernet if the IP address is unknown. Valin Corporation | www.valin.com Simple Ethernet Network Basics IP address is up to 12 digits (4 octets) Ex:192.168.1.1 For MOST PLC programming applications, the first 3 octets are the network address and the last is the node address. In above example 192.168.1 is network address, 1 is node address. For devices to communicate on a simple network: • Every device IP Network address must be the same. • Every device node number must be different. Device Laptop EX: Omron PLC 192.168.1.1 192.168.1.1 Device Laptop EX: Omron PLC 127.27.250.5 192.168.1.1 Device Laptop EX: Omron PLC 192.168.1.3 192.168.1.1 Valin Corporation | www.valin.com Omron Default IP Address • Most Omron Ethernet devices use one of the following IP addresses by default. Omron PLC 192.168.250.1 OR 192.168.1.1 Valin Corporation | www.valin.com PING Command • PING is a way to check if the device is connected (both virtually and physically) to the network. • Windows Command Prompt command. • PC must use the same network number as device (See previous) • Example: “ping 172.21.90.5” will test to see if a device with that IP address is connected to the PC. -
Xerox® Colorqube 8580/8880 Color Printer 3 System Administrator Guide
Xerox® ColorQube® 8580 / 8880 Color Printer Imprimante couleur System Administrator Guide Guide de l’administrateur système © 2015 Xerox Corporation. All rights reserved. Unpublished rights reserved under the copyright laws of the United States. Contents of this publication may not be reproduced in any form without permission of Xerox Corporation. Copyright protection claimed includes all forms of matters of copyrightable materials and information now allowed by statutory or judicial law or hereinafter granted, including without limitation, material generated from the software programs which are displayed on the screen such as styles, templates, icons, screen displays, looks, and so on. Xerox® and Xerox and Design®, Phaser®, PhaserSMART®, PhaserMatch®, PhaserCal®, PhaserMeter™, CentreWare®, PagePack®, eClick®, PrintingScout®, Walk-Up®, WorkCentre®, FreeFlow®, SMARTsend®, Scan to PC Desktop®, MeterAssistant®, SuppliesAssistant®, Xerox Secure Access Unified ID System®, Xerox Extensible Interface Platform®, ColorQube®, Global Print Driver®, and Mobile Express Driver® are trademarks of Xerox Corporation in the United States and/or other countries. Adobe® Reader®, Adobe® Type Manager®, ATM™, Flash®, Macromedia®, Photoshop®, and PostScript® are trademarks of Adobe Systems Incorporated in the United States and/or other countries. Apple, Bonjour, EtherTalk, TrueType, iPad, iPhone, iPod, iPod touch, Mac and Mac OS are trademarks of Apple Inc., registered in the U.S. and other countries. AirPrint and the AirPrint logo are trademarks of Apple Inc. HP-GL®, HP-UX®, and PCL® are trademarks of Hewlett-Packard Corporation in the United States and/or other countries. IBM® and AIX® are trademarks of International Business Machines Corporation in the United States and/or other countries. Microsoft®, Windows Vista®, Windows®, and Windows Server® are trademarks of Microsoft Corporation in the United States and other countries. -
Cs-204: Computer Networks
CS-204: COMPUTER NETWORKS Lecture 5 Chapter 19- Network Layer: Logical Addressing Instructor: Dr. Vandana Kushwaha 1. INTRODUCTION Communication at the network layer is host-to-host (computer-to-computer); a computer somewhere in the world needs to communicate with another computer somewhere else in the world. Usually, computers communicate through the Internet. The packet transmitted by the sending computer may pass through several LANs or WANs before reaching the destination computer. For this level of communication, we need a global addressing scheme; we called this logical addressing or IP address. 2. IPv4 ADDRESSES An IPv4 address is a 32-bit address that uniquely and universally defines the connection of a device (for example, a computer or a router) to the Internet. IPv4 addresses are unique. They are unique in the sense that each address defines one, and only one, connection to the Internet. Two devices on the Internet can never have the same address at the same time. But by using some strategies, an address may be assigned to a device for a time period and then taken away and assigned to another device. On the other hand, if a device operating at the network layer has m connections to the Internet, it needs to have m addresses. A router is such a device which needs as many IP addresses as the number of ports are there in it. 2.1. Address Space A protocol such as IPv4 that defines addresses has an address space. An address space is the total number of addresses used by the protocol. If a protocol uses N bits to define an address, the address space is 2N because each bit can have two different values (0 or 1) and N bits can have 2N values. -
Aerohive Configuration Guide: RADIUS Authentication | 2
Aerohive Configuration Guide RADIUS Authentication Aerohive Configuration Guide: RADIUS Authentication | 2 Copyright © 2012 Aerohive Networks, Inc. All rights reserved Aerohive Networks, Inc. 330 Gibraltar Drive Sunnyvale, CA 94089 P/N 330068-03, Rev. A To learn more about Aerohive products visit www.aerohive.com/techdocs Aerohive Networks, Inc. Aerohive Configuration Guide: RADIUS Authentication | 3 Contents Contents ...................................................................................................................................................................................................................... 3 IEEE 802.1X Primer................................................................................................................................................................................................... 4 Example 1: Single Site Authentication .................................................................................................................................................................... 6 Step 1: Configuring the Network Policy ..............................................................................................................................................................7 Step 2: Configuring the Interface and User Access .........................................................................................................................................7 Step 3: Uploading the Configuration and Certificates .................................................................................................................................... -
Multitech Bluetooth Network Access Point Administrator Guide S000619 Rev 1.2 for Use with Model: MT200B2E
MultiTech Bluetooth® Network Access Point Administrator Guide MultiTech Bluetooth Network Access Point Administrator Guide S000619 Rev 1.2 For use with model: MT200B2E Copyright This publication may not be reproduced, in whole or in part, without the specific and express prior written permission signed by an executive officer of Multi-Tech Systems, Inc. All rights reserved. Copyright © 2015 by Multi-Tech Systems, Inc. Multi-Tech Systems, Inc. makes no representations or warranties, whether express, implied or by estoppels, with respect to the content, information, material and recommendations herein and specifically disclaims any implied warranties of merchantability, fitness for any particular purpose and non- infringement. Multi-Tech Systems, Inc. reserves the right to revise this publication and to make changes from time to time in the content hereof without obligation of Multi-Tech Systems, Inc. to notify any person or organization of such revisions or changes. Trademarks MultiTech, MultiConnect, and the MultiTech logo are registered trademarks of Multi-Tech Systems, Inc. Bluetooth is a registered trademark of Bluetooth SIG, Inc. All other brand and product names are trademarks or registered trademarks of their respective companies. Contacting MultiTech Knowledge Base The Knowledge Base provides immediate access to support information and resolutions for all MultiTech products. Visit http://www.multitech.com/kb.go. Support Portal To create an account and submit a support case directly to our technical support team, visit: https://support.multitech.com Support Business Hours: M-F, 9am to 5pm CT Country By Email By Phone Europe, Middle East, Africa: [email protected] +(44) 118 959 7774 U.S., Canada, all others: [email protected] (800) 972-2439 or (763) 717-5863 World Headquarters Multi-Tech Systems, Inc. -
Internet Protocol Suite
InternetInternet ProtocolProtocol SuiteSuite Srinidhi Varadarajan InternetInternet ProtocolProtocol Suite:Suite: TransportTransport • TCP: Transmission Control Protocol • Byte stream transfer • Reliable, connection-oriented service • Point-to-point (one-to-one) service only • UDP: User Datagram Protocol • Unreliable (“best effort”) datagram service • Point-to-point, multicast (one-to-many), and • broadcast (one-to-all) InternetInternet ProtocolProtocol Suite:Suite: NetworkNetwork z IP: Internet Protocol – Unreliable service – Performs routing – Supported by routing protocols, • e.g. RIP, IS-IS, • OSPF, IGP, and BGP z ICMP: Internet Control Message Protocol – Used by IP (primarily) to exchange error and control messages with other nodes z IGMP: Internet Group Management Protocol – Used for controlling multicast (one-to-many transmission) for UDP datagrams InternetInternet ProtocolProtocol Suite:Suite: DataData LinkLink z ARP: Address Resolution Protocol – Translates from an IP (network) address to a network interface (hardware) address, e.g. IP address-to-Ethernet address or IP address-to- FDDI address z RARP: Reverse Address Resolution Protocol – Translates from a network interface (hardware) address to an IP (network) address AddressAddress ResolutionResolution ProtocolProtocol (ARP)(ARP) ARP Query What is the Ethernet Address of 130.245.20.2 Ethernet ARP Response IP Source 0A:03:23:65:09:FB IP Destination IP: 130.245.20.1 IP: 130.245.20.2 Ethernet: 0A:03:21:60:09:FA Ethernet: 0A:03:23:65:09:FB z Maps IP addresses to Ethernet Addresses -
Domain Name System System Work?
What is the DNS? - how it works Isaac Maposa | Dev Anand Teelucksingh | Beran Gillen Community Onboarding Program | 11 March 2017 Agenda 1 2 3 What is the Domain Structure of the How does the Name System? Domain Name Domain Name System System Work? 4 5 6 Who makes the Stakeholders in the Engage with ICANN Domain Name Domain Name ??? System Work? System. | 2 What is the Domain Name System (DNS)? The Internet, what is it..? ● The Internet is a network of networks that interconnects devices to exchange information. ● In order to “talk” to each other, all of these devices must have a unique numerical address called an Internet Protocol address or IP Address. An example of an IP address is 94.127.53.132 ● When you visit a website from your browser, you are requesting the website from your device’s IP address to the web server’s IP address. ● However, you don’t type in the ip address of the web server, rather the domain name of for example www.google.com ● In so doing, you have queried the DNS. ● So what is this DNS???? | 4 What is the Domain Name System? ● The Domain Name System or DNS overcomes this problem of remembering IP addresses by mapping domain names to IP addresses. ● While this sounds like a phone book, it is not a centralised database. ● The DNS is a distributed database across a hierarchy of networks of servers and provide ways for devices and software (like browsers and email) to query the DNS to get an IP address. ● Domain names must be unique. -
INTRODUCTION to SUBNETTING How to Maximize Network Addresses
Volume 1 • Issue 8 September–October 2000 Introduction to Industrial Ethernet, Part 5. Part 4 was featured in Issue 6, the MAY–JUNE 2000. If you would like a copy, please send your request to EXTENSION [email protected] A Technical Supplement to control NETWORK © 2000 Contemporary Control Systems, Inc. INTRODUCTION TO SUBNETTING How to maximize network addresses. By George Thomas, Contemporary Controls INTRODUCTION address to distinguish it from the Class Addressing other computers. With IP In a previous article we discussed addressing, servers and IPv4 is called a classful system the Internet Protocol and the workstations are all termed hosts under RFC 761 with IP addresses structure of IP addresses. An IP but each address not only identifies being defined as belonging to one address identifies the source and a host but the address of the of five classes A, B, C, D or E. destination of a directed or unicast network on which the host resides. Classes A, B and C define different possible combinations of network message and is defined in RFC 761. This is because IP is an and host addresses. Class D is IPv4 is the most common version internetworking protocol that not reserved for multicasting. of IP addressing requiring 32-bit only allows communication Multicasting is the ability of one addresses. Although IPv6, the 128- between hosts on the same host to communicate with many bit version, will be used in the network, but communication other hosts with one transmission future, this article will restrict the between hosts on different and is beyond the scope of this discussion to IPv4. -
NAT-Aware Public-Private GSLB Configuration Avi Networks — Technical Reference (17.2)
Page 1 of 5 NAT-aware Public-Private GSLB Configuration Avi Networks — Technical Reference (17.2) NAT-aware Public-Private GSLB Configuration view online An Avi GSLB configuration can serve clients from a mixture of public and private networks. Introduction Typically, the VIP configured in a local virtual service (configured as a GSLB pool member) is a private IP address. But this IP address may not always be reachable by the client. For example, a user on a laptop could come in via the corporate intranet or VPN, but also directly from the public Internet. In the former case, the source IP address would be an intranet private IP address. In the latter case, it would be a public IP address. Note that, with resolvers (LDNS) in the middle and no support for extension mechanism for DNS (EDNS), this may not be as simple. Note ? If EDNS processing is enabled, the client's IP address is found within the ECS option. For more information, refer to the Extension Mechanisms for DNS Client Subnet Option Insertion article. The source being a certain set of resolver IP addresses could indicate that the client is coming in from a private network, and another set of IP addresses could indicate that the client is coming in from a public network. How It Works Client DNS requests coming in from within the intranet have the private IP served in the A record, and requests from outside are served the public IP address. Please note that datapath health monitoring is performed only against the private IP address. -
New Gateways (PDF
Packet Network Notice Rev: 28-Nov-2011 Date: Nov 28, 2011 From: Santa Clara County ARES/RACES Packet Committee Subject: Packet Network Update – New AMPRnet and E-mail gateways Attention: All ECs, AECs, MACs and other Santa Clara County Packet Users This Packet Network Notice contains important information which affects your ability to access and use the county packet backbone. This update covers the following topics: • New AMPRnet Gateway • New E-mail Gateway Please read this information thoroughly and pass along to any packet users in your local area. New AMPRnet Gateway The AMPRnet is an AMateur Packet Radio network consisting of packet radio BBSs located worldwide. Local networks of BBSs are interconnected to other local networks through gateways. These gateways use IP-in-IP tunnels to connect to each other. AMPRnet IP addresses are allocated from the IP address block of 44.0.0.0/8. Once a BBS or local network of BBSs is connected to AMPRnet, each of the BBSs can reach any other BBS on the AMPRnet, and vice-versa. For example, in the State of Michigan, each county has a local network of one or more BBSs. Each county is connected to all other counties (and to the rest of the world) with AMPRnet connections. Here in California, we can use AMPRnet connections to reach other counties which do not have a radio path to our network. We have just started to reach out to other counties to work on making those connections. There are two primary uses for this connectivity: 1) Messaging: Messages can now be addressed to anyone at any of the AMPRnet BBSs with a simple and standard Internet-style address format: [email protected]. -
Building a Network
Building a network Data Communications and Computer Networks Lab EP1100 Ezzeldin Shereen Ming Zeng Peiyue Zhao Version 7.0 (2018) Department of Network and Systems Engineering School of Electrical Engineering and Computer Science KTH, Royal Institute of Technology Laboratory Manual 2 Chapter 1 Introduction 1.1 Purpose of the laboratory The main goal of this laboratory is to give you an overview of the different processes involved in building a network, such as a corporate network. You will have to plan the IP address scheme, configure and test the equipment, as well as configure several applications and servers typical of any corporate network (DNS servers for example). After you have completed the laboratory exercises, you should be familiar with the practical issues of the different concepts explained in the course, as well as with the real equipment used nowadays in computer networks. 1.2 Duties before the lab starts Students are required submit the homeworks before the lab starts. Students missing the homework submission will not be accepted to the lab. 1.2.1 Preparatory quizzes Each student has to complete two online lab entry quizzes, which can be found at the course web page. The quizzes are due on the first lab session, and the third. Their purpose is to check that you have enough theoretical knowledge of the tasks that you will perform in the lab. Since these tasks are not part of the course book, you will have to read this manual and its references carefully to pass the quizzes. 1.3 Rules of behavior in the laboratory 1.