Network Diagnostic on Linux (Basic Commands)
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HEP Computing Part I Intro to UNIX/LINUX Adrian Bevan
HEP Computing Part I Intro to UNIX/LINUX Adrian Bevan Lectures 1,2,3 [email protected] 1 Lecture 1 • Files and directories. • Introduce a number of simple UNIX commands for manipulation of files and directories. • communicating with remote machines [email protected] 2 What is LINUX • LINUX is the operating system (OS) kernel. • Sitting on top of the LINUX OS are a lot of utilities that help you do stuff. • You get a ‘LINUX distribution’ installed on your desktop/laptop. This is a sloppy way of saying you get the OS bundled with lots of useful utilities/applications. • Use LINUX to mean anything from the OS to the distribution we are using. • UNIX is an operating system that is very similar to LINUX (same command names, sometimes slightly different functionalities of commands etc). – There are usually enough subtle differences between LINUX and UNIX versions to keep you on your toes (e.g. Solaris and LINUX) when running applications on multiple platforms …be mindful of this if you use other UNIX flavours. – Mac OS X is based on a UNIX distribution. [email protected] 3 Accessing a machine • You need a user account you should all have one by now • can then log in at the terminal (i.e. sit in front of a machine and type in your user name and password to log in to it). • you can also log in remotely to a machine somewhere else RAL SLAC CERN London FNAL in2p3 [email protected] 4 The command line • A user interfaces with Linux by typing commands into a shell. -
System Calls and I/O
System Calls and I/O CS 241 January 27, 2012 Copyright ©: University of Illinois CS 241 Staff 1 This lecture Goals Get you familiar with necessary basic system & I/O calls to do programming Things covered in this lecture Basic file system calls I/O calls Signals Note: we will come back later to discuss the above things at the concept level Copyright ©: University of Illinois CS 241 Staff 2 System Calls versus Function Calls? Copyright ©: University of Illinois CS 241 Staff 3 System Calls versus Function Calls Function Call Process fnCall() Caller and callee are in the same Process - Same user - Same “domain of trust” Copyright ©: University of Illinois CS 241 Staff 4 System Calls versus Function Calls Function Call System Call Process Process fnCall() sysCall() OS Caller and callee are in the same Process - Same user - OS is trusted; user is not. - Same “domain of trust” - OS has super-privileges; user does not - Must take measures to prevent abuse Copyright ©: University of Illinois CS 241 Staff 5 System Calls System Calls A request to the operating system to perform some activity System calls are expensive The system needs to perform many things before executing a system call The computer (hardware) saves its state The OS code takes control of the CPU, privileges are updated. The OS examines the call parameters The OS performs the requested function The OS saves its state (and call results) The OS returns control of the CPU to the caller Copyright ©: University of Illinois CS 241 Staff 6 Steps for Making a System Call -
Lab Exercise – Ipv4
Lab Exercise – IPv4 Objective To learn about the details of IP (Internet Protocol). IP is the network layer protocol used throughout the Internet. We will examine IP version 4, since it is ubiquitously deployed, while the IP version 6 is partly deployed. The trace is here: https://kevincurran.org/com320/labs/wireshark/trace-ipv4.pcap The text file is here: https://kevincurran.org/com320/labs/wireshark/trace-ipv4.txt Requirements Wireshark: This lab uses the Wireshark software tool to capture and examine a packet trace. A packet trace is a record of traffic at a location on the network, as if a snapshot was taken of all the bits that passed across a particular wire. The packet trace records a timestamp for each packet, along with the bits that make up the packet, from the lower-layer headers to the higher-layer contents. Wireshark runs on most operating systems, including Windows, Mac and Linux. It provides a graphical UI that shows the sequence of packets and the meaning of the bits when interpreted as protocol headers and data. It col- or-codes packets by their type, and has various ways to filter and analyze packets to let you investigate the behavior of network protocols. Wireshark is widely used to troubleshoot networks. You can down- load it from www.wireshark.org if it is not already installed on your computer. We highly recommend that you watch the short, 5 minute video “Introduction to Wireshark” that is on the site. wget / curl: This lab uses wget (Linux and Windows) and curl (Mac) to fetch web resources. -
1 Introduction
Technical report, IDE1202, February 2012 Enhancing Network Security in Linux Environment Master Thesis in Computer Network Engineering By Ali Mohammed, Sachin Sama and Majeed Mohammed School of Information Science, Computer and Electrical Engineering Halmstad University i Enhancing Network Security in Linux Environment Master Thesis in Computer Network Engineering School of Information Science, Computer and Electrical Engineering Halmstad University Box 823, S-301 18 Halmstad, Sweden February 2012 ii Preface First of all, we would like to express our sincere gratitude to our Supervisor Philip Heimer and Professor Tony Larsson for their supervision and assistance in the entire thesis work. We are also thankful to IDE department, Halmstad University for providing this opportunity to complete this thesis. Ali Mohammed Sachin Sama Majeed Mohammed iii iv Abstract Designing a secured network is the most important task in any enterprise or organization development. Securing a network mainly involves applying policies and procedures to protect different network devices from unauthorized access. Servers such as web servers, file servers, mail servers, etc., are the important devices in a network. Therefore, securing these servers is the first and foremost step followed in every security implementation mechanism. To implement this, it is very important to analyse and study the security mechanisms provided by the operating system. This makes it easier for security implementation in a network. This thesis work demonstrates the tasks needed to enhance the network security in Linux environment. The various security modules existing in Linux makes it different from other operating systems. The security measures which are mainly needed to enhance the system security are documented as a baseline for practical implementation. -
Useful Tai Ls Dino
SCIENCE & NATURE Useful Tails Materials Pictures of a possum, horse, lizard, rattlesnake, peacock, fish, bird, and beaver What to do 1. Display the animal pictures so the children can see them. 2. Say the following sentences. Ask the children to guess the animal by the usefulness of its tail. I use my tail for hanging upside down. (possum) I use my tail as a fly swatter. (horse) When my tail breaks off, I grow a new one. (lizard) I shake my noisy tail when I am about to strike. (rattlesnake) My tail opens like a beautiful fan. (peacock) I use my tail as a propeller. I cannot swim without it. (fish) I can’t fly without my tail. (bird) I use my powerful tail for building. (beaver) More to do Ask the children if they can name other animals that have tails. Ask them how these animals’Downloaded tails might by [email protected] useful. from Games: Cut out the tailsProFilePlanner.com of each of the animals. Encourage the children to pin the tails on the pictures (like “Pin the Tail on the Donkey”). Dotti Enderle, Richmond, TX Dino Dig Materials Plastic or rubber dinosaurs or bones Sand Wide-tip, medium-sized paintbrushes Plastic sand shovels Small plastic buckets Clipboards Paper Pencil or pens 508 The GIANT Encyclopedia of Preschool Activities for Four-Year-Olds Downloaded by [email protected] from ProFilePlanner.com SCIENCE & NATURE What to do 1. Beforehand, hide plastic or rubber dinosaurs or bones in the sand. 2. Give each child a paintbrush, shovel, and bucket. 3. -
K30503041: Creating a Virtual Server with ARP And/Or ICMP Disabled at Creation
K30503041: Creating a virtual server with ARP and/or ICMP disabled at creation Non-Diagnostic Original Publication Date: Apr 16, 2020 Update Date: Apr 16, 2020 Topic You should consider using this procedure under the following condition: You want to create a new virtual server with the Address Resolution Protocol (ARP) and/or the Internet Control Message Protocol (ICMP) disabled at creation. Description In some network environments, you may want to create virtual servers that have ARP and/or ICMP disabled. When creating a new virtual server (one that does not use an IP address of an existing virtual server), you can enable or disable the virtual server. However, you cannot set the IP address of the virtual server with ARP and/or ICMP to 'disabled' when creating the virtual server. You can only enable or disable ARP or ICMP by modifying the virtual address that is automatically created when you create the virtual server. In this scenario, you create the virtual address with ARP and ICMP enabled at the time of creation. You can work around this scenario by creating the virtual address for the virtual server in advance with ARP and/or ICMP disabled. After creating the virtual address, you can then create the virtual server that references the same IP address of the virtual address as the destination IP address of the virtual server. Prerequisites You must meet the following prerequisite to use this procedure: Administrative access to the BIG-IP Configuration utility or the TMOS Shell (tmsh). Note: You cannot create a virtual address using the Configuration utility. -
Openssh-Ldap-Pubkey Documentation Release 0.3.0
openssh-ldap-pubkey Documentation Release 0.3.0 Kouhei Maeda May 18, 2020 Contents 1 openssh-ldap-pubkey 3 1.1 Status...................................................3 1.2 Requirements...............................................3 1.3 See also..................................................3 2 How to setup LDAP server for openssh-lpk5 2.1 Precondition...............................................5 2.2 Requirements...............................................5 2.3 Install...................................................5 3 How to setup OpenSSH server9 3.1 Precondition...............................................9 3.2 Requirements...............................................9 3.3 Install with nslcd (recommend).....................................9 3.4 Install without nslcd........................................... 11 4 History 13 4.1 0.3.0 (2020-05-18)............................................ 13 4.2 0.2.0 (2018-09-30)............................................ 13 4.3 0.1.3 (2018-08-18)............................................ 13 4.4 0.1.2 (2017-11-25)............................................ 13 4.5 0.1.1 (2015-10-16)............................................ 14 4.6 0.1.0 (2015-10-16)............................................ 14 5 Contributors 15 6 Indices and tables 17 i ii openssh-ldap-pubkey Documentation, Release 0.3.0 Contents: Contents 1 openssh-ldap-pubkey Documentation, Release 0.3.0 2 Contents CHAPTER 1 openssh-ldap-pubkey 1.1 Status 1.2 Requirements 1.2.1 LDAP server • Add openssh-lpk schema. • Add an objectClass ldapPublicKey to user entry. • Add one or more sshPublicKey attribute to user entry. 1.2.2 OpenSSH server • OpenSSH over 6.2. • Installing this utility. • Setup AuthorozedKeysCommand and AuthorizedKeysCommandUser in sshd_config. 1.3 See also • OpenSSH 6.2 release 3 openssh-ldap-pubkey Documentation, Release 0.3.0 • openssh-lpk 4 Chapter 1. openssh-ldap-pubkey CHAPTER 2 How to setup LDAP server for openssh-lpk 2.1 Precondition This article restricts OpenLDAP with slapd_config on Debian systems only. -
Curl User Survey 2019 Analysis
curl user survey 2019 analysis “there are so many useful features” summary and analysis by Daniel Stenberg version 1 - June 4, 2019 Table of Contents About curl.............................................................................................................................................3 Survey Background..........................................................................................................................3 Number of responses............................................................................................................................4 Returning respondents?........................................................................................................................5 Users living where?..............................................................................................................................6 What kind of users?..............................................................................................................................7 What protocols......................................................................................................................................8 Multiple platforms..............................................................................................................................10 What platforms...................................................................................................................................11 Which Windows versions...................................................................................................................13 -
Improving Networking
IMPERIAL COLLEGE LONDON FINALYEARPROJECT JUNE 14, 2010 Improving Networking by moving the network stack to userspace Author: Matthew WHITWORTH Supervisor: Dr. Naranker DULAY 2 Abstract In our modern, networked world the software, protocols and algorithms involved in communication are among some of the most critical parts of an operating system. The core communication software in most modern systems is the network stack, but its basic monolithic design and functioning has remained unchanged for decades. Here we present an adaptable user-space network stack, as an addition to my operating system Whitix. The ideas and concepts presented in this report, however, are applicable to any mainstream operating system. We show how re-imagining the whole architecture of networking in a modern operating system offers numerous benefits for stack-application interactivity, protocol extensibility, and improvements in network throughput and latency. 3 4 Acknowledgements I would like to thank Naranker Dulay for supervising me during the course of this project. His time spent offering constructive feedback about the progress of the project is very much appreciated. I would also like to thank my family and friends for their support, and also anybody who has contributed to Whitix in the past or offered encouragement with the project. 5 6 Contents 1 Introduction 11 1.1 Motivation.................................... 11 1.1.1 Adaptability and interactivity.................... 11 1.1.2 Multiprocessor systems and locking................ 12 1.1.3 Cache performance.......................... 14 1.2 Whitix....................................... 14 1.3 Outline...................................... 15 2 Hardware and the LDL 17 2.1 Architectural overview............................. 17 2.2 Network drivers................................. 18 2.2.1 Driver and device setup....................... -
Shell Variables
Shell Using the command line Orna Agmon ladypine at vipe.technion.ac.il Haifux Shell – p. 1/55 TOC Various shells Customizing the shell getting help and information Combining simple and useful commands output redirection lists of commands job control environment variables Remote shell textual editors textual clients references Shell – p. 2/55 What is the shell? The shell is the wrapper around the system: a communication means between the user and the system The shell is the manner in which the user can interact with the system through the terminal. The shell is also a script interpreter. The simplest script is a bunch of shell commands. Shell scripts are used in order to boot the system. The user can also write and execute shell scripts. Shell – p. 3/55 Shell - which shell? There are several kinds of shells. For example, bash (Bourne Again Shell), csh, tcsh, zsh, ksh (Korn Shell). The most important shell is bash, since it is available on almost every free Unix system. The Linux system scripts use bash. The default shell for the user is set in the /etc/passwd file. Here is a line out of this file for example: dana:x:500:500:Dana,,,:/home/dana:/bin/bash This line means that user dana uses bash (located on the system at /bin/bash) as her default shell. Shell – p. 4/55 Starting to work in another shell If Dana wishes to temporarily use another shell, she can simply call this shell from the command line: [dana@granada ˜]$ bash dana@granada:˜$ #In bash now dana@granada:˜$ exit [dana@granada ˜]$ bash dana@granada:˜$ #In bash now, going to hit ctrl D dana@granada:˜$ exit [dana@granada ˜]$ #In original shell now Shell – p. -
Useful Commands in Linux and Other Tools for Quality Control
Useful commands in Linux and other tools for quality control Ignacio Aguilar INIA Uruguay 05-2018 Unix Basic Commands pwd show working directory ls list files in working directory ll as before but with more information mkdir d make a directory d cd d change to directory d Copy and moving commands To copy file cp /home/user/is . To copy file directory cp –r /home/folder . to move file aa into bb in folder test mv aa ./test/bb To delete rm yy delete the file yy rm –r xx delete the folder xx Redirections & pipe Redirection useful to read/write from file !! aa < bb program aa reads from file bb blupf90 < in aa > bb program aa write in file bb blupf90 < in > log Redirections & pipe “|” similar to redirection but instead to write to a file, passes content as input to other command tee copy standard input to standard output and save in a file echo copy stream to standard output Example: program blupf90 reads name of parameter file and writes output in terminal and in file log echo par.b90 | blupf90 | tee blup.log Other popular commands head file print first 10 lines list file page-by-page tail file print last 10 lines less file list file line-by-line or page-by-page wc –l file count lines grep text file find lines that contains text cat file1 fiel2 concatenate files sort sort file cut cuts specific columns join join lines of two files on specific columns paste paste lines of two file expand replace TAB with spaces uniq retain unique lines on a sorted file head / tail $ head pedigree.txt 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 10 -
ENT-UG1060 User Guide Software API Programming
ENT-UG1060 User Guide Software API Programming Microsemi Corporation (Nasdaq: MSCC) offers a comprehensive portfolio of semiconductor and system solutions for communications, defense & security, aerospace and industrial markets. Products include high-performance and radiation-hardened analog mixed-signal integrated circuits, FPGAs, SoCs and ASICs; power management products; timing and synchronization devices and precise time solutions, setting the world's standard for time; voice processing devices; RF solutions; discrete components; security technologies and scalable anti-tamper products; Ethernet solutions; Power-over-Ethernet ICs and midspans; as well as custom design capabilities and services. Microsemi is headquartered in Aliso Viejo, Calif, and has approximately 3,600 employees globally. Learn more at www.microsemi.com. Microsemi Corporate Headquarters Microsemi makes no warranty, representation, or guarantee regarding the information contained herein or One Enterprise, Aliso Viejo, the suitability of its products and services for any particular purpose, nor does Microsemi assume any CA 92656 USA liability whatsoever arising out of the application or use of any product or circuit. The products sold hereunder and any other products sold by Microsemi have been subject to limited testing and should not Within the USA: +1 (800) 713-4113 be used in conjunction with mission-critical equipment or applications. Any performance specifications are Outside the USA: +1 (949) 380-6100 believed to be reliable but are not verified, and Buyer must conduct and complete all performance and Sales: +1 (949) 380-6136 other testing of the products, alone and together with, or installed in, any end-products. Buyer shall not rely Fax: +1 (949) 215-4996 on any data and performance specifications or parameters provided by Microsemi.