DOCSLIB.ORG

Weaknesses in the Node.Js Event-Driven Architecture

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Weaknesses in the Node.Js Event-Driven Architecture The Case of the Poisoned Event Handler: Weaknesses in the Node.js Event-Driven Architecture James Davis Gregor Kildow Dongyoon Lee Virginia Tech Virginia Tech Virginia Tech Blacksburg, VA, USA Blacksburg, VA, USA Blacksburg, VA, USA [email protected] [email protected] [email protected] ABSTRACT and pending events are handled by an event thread. The Node.js has seen rapid adoption in industry and the open- event thread may offload expensive activity to a small, fixed- source community. Unfortunately, its event-driven architec- size worker pool, which generates an event to note the com- ture exposes Node.js applications to Event Handler-Poisoning pletion of each offloaded task. The worker pool is typi- denial of service attacks. Our evaluation of the state of prac- cally implemented using threads or separate processes, and tice in Node.js| combining a study of 353 publicly reported performs services like offering \asynchronous" (blocking but security vulnerabilities and a survey of 151 representative concurrent) access to the file system. This architecture is common to all mainstream general-purpose EDA frameworks npm modules | demonstrates that the community is not equipped to combat this class of attack. We recommend today, discussed further in Section 2.2. several changes to the state of practice and propose both programming language and runtime approaches to defend against Event Handler-Poisoning attacks. Keywords Node.js; Event-driven architecture; Denial of service; ReDoS 1. INTRODUCTION The Event-Driven Architecture (EDA) is coming into its own. Although EDA approaches have been discussed and implemented in the academic and professional communities Figure 1: Classic Event-Driven Architecture. In- for decades (e.g. [17, 7, 18, 13]), historically EDA has coming events are handled sequentially by the event only seen wide adoption in user interface settings like web thread. The event thread may offload tasks to the browsers. It is increasingly relevant in systems programming worker pool. today thanks to the explosion of interest in Node.js1, an event-driven server-side JavaScript framework. In applications built using EDA, there is a set of possible Server-side applications implemented using the EDA are events (e.g. \mouse click" or \incoming network traffic") for vulnerable to a unique type of denial of service attack which which the developer supplies a set of Event Handlers (also we term the Event Handler-Poisoning (EHP) attack. Key known as callbacks); these Event Handlers will be executed to the EDA is the use of a small, fixed-size set of Event when the corresponding events occur [5]. During the execu- Handlers that handle each event in turn. In the EDA design tion of such an application, events are generated by external of Figure 1, there are two classes of Event Handlers: the activity and routed to the appropriate Event Handlers. event thread, and the workers in the worker pool. If either Figure 1 illustrates the classic EDA formulation, known as class of Event Handlers (the event thread, or every worker AMPED [11]: the operating system or a framework places in the worker pool) becomes blocked, the handling of every events in a queue (e.g. through Linux's poll system call2), pending event will be delayed. While in a One Thread Per Client (OTPC) setting an 1See https://nodejs.org/en/. expensive request from a client delays only that client, in the 2Per the Linux man page, \poll...waits for one of a set of file EDA context an expensive request delays every client. Thus, Permission to make digital or hard copies of all or part of this work for personal or the EDA model resurrects an old foe: DoS vulnerabilities in classroom use is granted without fee provided that copies are not made or distributed an essentially single-threaded server. for profit or commercial advantage and that copies bear this notice and the full citation Event Handlers might block due to an expensive computa- on the first page. Copyrights for components of this work owned by others than the tion or due to I/O. In our study of the state of practice in the author(s) must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission Node.js community in Section 4.3, developers appear to be and/or a fee. Request permissions from [email protected]. well apprised of the risks associated with blocking I/O. How- EuroSec’17, April 23 2017, Belgrade, Serbia ever, a surprising number of developers appear to take a cav- c 2017 Copyright held by the owner/author(s). Publication rights licensed to ACM. alier approach to the possibility of blocking the event thread ISBN 978-1-4503-4935-2/17/04. $15.00 DOI: http://dx.doi.org/10.1145/3065913.3065916 descriptors to become ready to perform I/O." with computation, as shown in Section 6.2. The prevalence Framework Contributors Commits Releases of EHP vulnerabilities in many common modules suggests Node.js 1176 15666 399 the need for reform in the community's practices, and for libuv 247 3643 183 both programming language and runtime aids to facilitate EventMachine 113 1141 27 community adoption. Reactor 56 4249 42 1.1 Contributions Twisted 35 20751 38 This paper makes the following contributions: Table 1: Popularity of event-driven programming environments measured by development activity. 1. After identifying Node.js as the most popular general Data were obtained from GitHub in December 2016. EDA framework, we analyze the 353 security vulner- abilities publicized in its package ecosystem, npm. We identify and discuss the CPU-bound and I/O-bound GitHub survey are shown in Table 1, and show that Node.js EHP vulnerabilities among them. has by far the largest developer community and a significant 2. We evaluate the ease with which a Node.js developer number of commits. can avoid EHP vulnerabilities. Our assessment of de- Node.js is a server-side event-driven framework for velopment aids and our study of 151 npm modules iden- JavaScript that uses the architecture shown in Figure 1. The tify significant shortcomings in the tools, documenta- worker pool is used internally to perform asynchronous DNS tion, and modules on which a developer might rely. queries and file system I/O. In addition, user-defined code can be offloaded to the worker pool. Node.js claims 3.5 mil- 3. We discuss ways to reduce EHP vulnerabilities in the lion users [1], and its open-source package ecosystem, npm, is Node.js ecosystem through changes in the community's the largest of any programming language or framework10. practices and by various programming language and Though Node.js has seen significant use in industry (e.g. runtime defenses. LinkedIn11, PayPal12, eBay13, and IBM14), to the best of our knowledge the only academic engagement with security 2. BACKGROUND aspects of Node.js applications was Ojamaa et al.'s high-level survey [10]. We believe that more academic involvement in In this section we compare the EDA with the OTPC ar- the Node.js community will increase the security of many of chitecture. We then identify the most popular server-side the web services we use every day. EDA framework for analysis. Lastly, we discuss two types of EHP vulnerabilities in the EDA. 2.3 Event Handler-Poisoning Attacks 2.1 EDA vs. OTPC The key characteristic of the EDA is that many request There are two main architectures for scalable web servers. events are addressed by a small number of Event Handlers. The traditional approach is the OTPC architecture, of which An Event Handler-Poisoning attack exploits this design by Apache3 is the most prominent. In the OTPC style, a thread causing the Event Handlers to block indefinitely, poisoning or a process is assigned to each client, with a large maximum them. This is done through the submission of an expensive number of concurrent clients. The OTPC model isolates task, either CPU-bound or I/O-bound. clients from one another, reducing the risk of interference. We emphasize that in the EDA design of Figure 1, of- However, each additional client incurs memory and context floading tasks to a fixed-size worker pool is not a panacea switching overhead. In contrast, by multiplexing multiple for EHP vulnerabilities. Suppose an attacker identifies an client connections into a single thread and offering a small EHP vulnerability in code executed by the worker pool. A worker pool for asynchronous tasks, an EDA approach sig- pool of size k will jam after only k poisonous requests; the nificantly reduces a server's per-client resource use. But the EHP vulnerability is essentially the same whether the attack EDA model also exposes the server to instability, e.g. due is against the event thread or the worker pool. Therefore, to vulnerabilities like EHP. an attacker's aim is to submit requests that cause either the event thread or the entire worker pool to jam up, thereby 2.2 General-Purpose EDA Frameworks delaying the handling of subsequent requests. Though an EDA approach can be implemented in most It should be noted that an attack that jams the worker programming languages, the mainstream general-purpose pool can in principle be carried out against any architecture EDA frameworks for server applications are Java/Reactor4, or system with a cap on the amount of resources available C/libuv5, Python/Twisted6, Ruby/EventMachine7, and for clients, including both EDA and pool-based OTPC de- JavaScript/Node.js8. To capture the scope and variety of ac- signs. However, the connection pool in a OTPC system is tivity for each framework, we surveyed each of their GitHub9 significantly larger than the worker pool in typical EDA im- repositories using the metrics of number of commits, number plementations.
Load more

Recommended publications
  • Knot DNS Resolver Release 1.2.0
    Knot DNS Resolver Release 1.2.0 CZ.NIC Labs Apr 25, 2017 Contents 1 Building project 3 1.1 Installing from packages.........................................3 1.2 Platform considerations.........................................3 1.3 Requirements...............................................3 1.4 Building from sources..........................................5 1.5 Getting Docker image..........................................7 2 Knot DNS Resolver library 9 2.1 Requirements...............................................9 2.2 For users.................................................9 2.3 For developers..............................................9 2.4 Writing layers.............................................. 11 2.5 APIs in Lua................................................ 12 2.6 API reference............................................... 15 3 Knot DNS Resolver daemon 47 3.1 Enabling DNSSEC............................................ 47 3.2 CLI interface............................................... 48 3.3 Scaling out................................................ 48 3.4 Running supervised........................................... 49 3.5 Configuration............................................... 49 3.6 Using CLI tools............................................. 64 4 Knot DNS Resolver modules 67 4.1 Static hints................................................ 67 4.2 Statistics collector............................................ 69 4.3 Query policies.............................................. 71 4.4 Views and ACLs............................................
    [Show full text]
  • Safeguard for Privileged Passwords 6.0.9 LTS Release Notes
    Safeguard for Privileged Passwords 6.0.9 LTS Release Notes 03 March 2021, 06:20 These release notes provide information about the Safeguard for Privileged Passwords 6.0.9 LTS release. If you are updating a Safeguard for Privileged Passwords version prior to this release, read the release notes for the version found at: One Identity Safeguard for Privileged Passwords Technical Documentation. For the most recent documents and product information, see One Identity Safeguard for Privileged Passwords Technical Documentation. Release options Safeguard for Privileged Passwords includes two release versions: l Long Term Support (LTS) release, version 6.0.9 LTS l Feature release, version 6.9 The versions align with Safeguard for Privileged Sessions. For more information, see Long Term Support (LTS) and Feature Releases on page 13. About this release Safeguard for Privileged Passwords Version 6.0.9 LTS is a minor LTS release with resolved issues. For more details on the features and resolved issues, see: Safeguard for Privileged Passwords 6.0.9 LTS 1 Release Notes l Resolved issues NOTE: For a full list of key features in Safeguard for Privileged Passwords, see the Safeguard for Privileged Passwords Administration Guide. About the Safeguard product line The Safeguard for Privileged Passwords Appliance is built specifically for use only with the Safeguard for Privileged Passwords privileged management software, which is pre- installed and ready for immediate use. The appliance is hardened to ensure the system is secured at the hardware, operating system, and software levels. The hardened appliance approach protects the privileged management software from attacks while simplifying deployment and ongoing management and shortening the time frame to value.
    [Show full text]
  • Efficient Parallel I/O on Multi-Core Architectures
    Lecture series title/ lecture title Efficient parallel I/O on multi-core architectures Adrien Devresse CERN IT-SDC-ID Thematic CERN School of Computing 2014 1 Author(s) names – Affiliation Lecture series title/ lecture title How to make I/O bound application scale with multi-core ? What is an IO bound application ? → A server application → A job that accesses big number of files → An application that uses intensively network 2 Author(s) names – Affiliation Lecture series title/ lecture title Stupid example: Simple server monothreaded // create socket socket_desc = socket(AF_INET , SOCK_STREAM , 0); // bind the socket bind(socket_desc,(struct sockaddr *)&server , sizeof(server)); listen(socket_desc , 100); //accept connection from an incoming client while(1){ // declarations client_sock = accept(socket_desc, (struct sockaddr *)&client, &c); //Receive a message from client while( (read_size = recv(client_sock , client_message , 2000 , 0)) > 0{ // Wonderful, we have a client, do some useful work std::string msg("hello bob"); write(client_sock, msg.c_str(), msg.size()); } } 3 Author(s) names – Affiliation Lecture series title/ lecture title Stupid example: Let's make it parallel ! int main(int argc, char** argv){ // creat socket void do_work(int socket){ socket_desc = socket(AF_INET , SOCK_STREAM , 0); //Receive a message while( (read_size = // bind the socket recv(client_sock , bind(socket_desc, server , sizeof(server)); client_message , 2000 , 0)) > 0{ listen(socket_desc , 100); // Wonderful, we have a client // useful works //accept connection
    [Show full text]
  • Message Passing and Network Programming
    Message Passing and Network Programming Advanced Operating Systems Lecture 13 Colin Perkins | https://csperkins.org/ | Copyright © 2017 | This work is licensed under the Creative Commons Attribution-NoDerivatives 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nd/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. Lecture Outline • Actors, sockets, and network protocols • Asynchronous I/O frameworks • Higher level abstractions Colin Perkins | https://csperkins.org/ | Copyright © 2017 2 Message Passing and Network Protocols • Recap: • Actor-based framework for message passing Send to • Each actor has a receive loop other actors Mailbox Actor Calls to one function per state Queue • Receive Message • Messages delivered by runtime system; Receiver processed sequentially Message Done Message Process • Actor can send messages in reply; Message Dispatcher return identity of next state Dequeue • Can we write network code this way? Request next • Send data by sending a message to an actor representing a socket • Receive messages representing data received on a socket Colin Perkins | https://csperkins.org/ | Copyright © 2017 3 Integrating Actors and Sockets Sending Thread Send to other actors Encoder Network Socket Mailbox Actor Queue Parser Receive Message Receiver Message Done Receiving Thread Message Process Message Dispatcher • Conceptually straightforward to integrate Dequeue actors with network code Request next • Runtime system maintains sending and
    [Show full text]
  • Copyright by Tongliang Liao 2017
    Copyright by Tongliang Liao 2017 The Thesis committee for Tongliang Liao certifies that this is the approved version of the following thesis: TAI: Threaded Asynchronous I/O Library for Performance and Portability APPROVED BY SUPERVISING COMMITTEE: Vijaychidambaram Velayudhan Pillai, Supervisor Simon Peter TAI: Threaded Asynchronous I/O Library for Performance and Portability by Tongliang Liao Thesis Presented to the Faculty of the Graduate School of the University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of Master of Science in Computer Science The University of Texas at Austin Dec 2017 TAI: Threaded Asynchronous I/O Library for Performance and Portability by Tongliang Liao, M.S.C.S The University of Texas at Austin, 2017 Supervisor: Vijaychidambaram Velayudhan Pillai In this paper, we investigate the behavior and performance of disk I/O using different types of libraries. We analyze the scenario where we can benefit from asyn- chronous I/O, and propose our cross-platform library design called TAI (Threaded Async I/O). TAI is designed to be a C++17 library with developer-friendly API. Our benchmark shows it can out-perform other libraries when asynchronous I/O is beneficial, and keep competitive speed in other cases. It also demonstrates TAI’s ability to retrieve 20% - 60% speedup on poorly scaled serial code by a simple library replacement. iv Table of Contents 1 Introduction 1 1.1 Related Work .................................................................................. 2 1.2 Background ..................................................................................... 2 1.2.1 POSIX Sync I/O ................................................................... 3 1.2.2 POSIX AIO .......................................................................... 3 1.2.3 C/C++ Standard I/O Functions............................................
    [Show full text]
  • A Sense of Time for Node.Js: Timeouts As a Cure for Event Handler Poisoning
    A Sense of Time for Node.js: Timeouts as a Cure for Event Handler Poisoning Anonymous Abstract—The software development community has begun to new Denial of Service attack that can be used against EDA- adopt the Event-Driven Architecture (EDA) to provide scalable based services. Our Event Handler Poisoning attack exploits web services. Though the Event-Driven Architecture can offer the most important limited resource in the EDA: the Event better scalability than the One Thread Per Client Architecture, Handlers themselves. its use exposes service providers to a Denial of Service attack that we call Event Handler Poisoning (EHP). The source of the EDA’s scalability is also its Achilles’ heel. Multiplexing unrelated work onto the same thread re- This work is the first to define EHP attacks. After examining EHP vulnerabilities in the popular Node.js EDA framework and duces overhead, but it also moves the burden of time sharing open-source npm modules, we explore various solutions to EHP- out of the thread library or operating system and into the safety. For a practical defense against EHP attacks, we propose application itself. Where OTPCA-based services can rely on Node.cure, which defends a large class of Node.js applications preemptive multitasking to ensure that resources are shared against all known EHP attacks by making timeouts a first-class fairly, using the EDA requires the service to enforce its own member of the JavaScript language and the Node.js framework. cooperative multitasking [89]. An EHP attack identifies a way to defeat the cooperative multitasking used by an EDA-based Our evaluation shows that Node.cure is effective, broadly applicable, and offers strong security guarantees.
    [Show full text]
  • Event Handler Poisoning: Attacks and Defenses
    Event Handler Poisoning: Attacks and Defenses Anonymous Anonymous [email protected] Abstract—The software development community has begun to are the first to examine the security implications of using the adopt the Event-Driven Architecture (EDA) to provide scalable EDA at a software architecture-level. In xIII we describe a web services. Though the Event-Driven Architecture can offer new Denial of Service attack that can be used against EDA- better scalability than the One Thread Per Client Architecture, based services. Our Event Handler Poisoning attack identifies its use exposes service providers to a Denial of Service attack the most important limited resource in the EDA: the Event that we call Event Handler Poisoning (EHP). With the rise in the Handlers themselves. use of the EDA may come a plague of EHP attacks threatening critical Internet services. The EDA’s scalability is also its Achilles’ heel. Multiplex- In this work we define EHP attacks, dividing them into ing unrelated work onto the same thread reduces overhead, two types, CPU-bound and I/O-bound. After examining EHP but it also moves the burden of time sharing out of the thread vulnerabilities in the popular Node.js EDA framework and open- library or operating system and into the application itself. source npm modules, we explore two representative EHP attacks Where OTPCA-based services can rely on the preemptive in detail: Regular Expression Denial of Service (ReDoS) and I/O- multitasking promised by the underlying system to ensure based Denial of Service (IODoS). that resources are shared fairly, using the EDA requires the Using our Constant Worst-Case Execution Time (C-WCET) service to enforce its own cooperative multitasking [48].
    [Show full text]
  • Enhancing Quality of Service Metrics for High Fan-In Node.Js Applications by Optimising the Network Stack
    DEGREE PROJECT, IN COMPUTER SCIENCE , SECOND LEVEL LAUSANNE, SWITZERLAND 2015 Enhancing Quality of Service Metrics for High Fan-In Node.js Applications by Optimising the Network Stack LEVERAGING IX: THE DATAPLANE OPERATING SYSTEM FREDRIK PETER LILKAER KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF COMPUTER SCIENCE AND COMMUNICATION (CSC) Enhancing Quality of Service Metrics for High Fan-in Node.js Applications by Optimising the Network Stack -Leveraging IX: The Dataplane Operating System FREDRIK PETER LILKAER DD221X, Master’s Thesis in Computer Science (30 ECTS credits) Degree Progr. in Computer Science and Engineering 300 credits Master Programme in Computer Science 120 credits Royal Institute of Technology year 2015 Supervisor at EPFL was Edouard Bugnion Supervisor at CSC wa s Carl-Henrik Ek Examiner wa s Johan Håstad Presented: 2015-10-01 Royal Institute of Technology School of Computer Science and Communication KTH CSC SE-100 44 Stockholm, Sweden URL: www.kth.se/csc Abstract This thesis investigates the feasibility of porting Node.js, a JavaScript web application framework and server, to IX, a data- plane operating system specifically developed to meet the needs of high performance microsecond-computing type of applications in a datacentre setting. We show that porting requires exten- sions to the IX kernel to support UDS polling, which we imple- ment. We develop a distributed load generator to benchmark the framework. The results show that running Node.js on IX improves throughput by up to 20.6%, latency by up to 5.23×, and tail latency by up to 5.68× compared to a Linux baseline. We show how server side request level reordering affect the la- tency distribution, predominantly in cases where the server is load saturated.
    [Show full text]
  • Oracle Communications Messaging Server Licensing Information User Manual Third-Party Notices
    Oracle® Communications Messaging Server Licensing Information User Manual Release 8.1 F15145-03 April 2021 Copyright © 2008, 2021, Oracle and/or its affiliates. This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited. The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing. If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, then the following notice is applicable: U.S. GOVERNMENT END USERS: Oracle programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are “commercial computer software” pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of the programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, shall be subject to license terms and license restrictions applicable to the programs. No other rights are granted to the U.S. Government. This software or hardware is developed for general use in a variety of information management applications.
    [Show full text]
  • Open Source Software Used in Cisco Nexus 1000V for Vmware Vsphere, Release 5.2(1)SV3(2.5)
    Open Source Used In Cisco Nexus 1000V Switch for VMware vSphere 5.2(1)SV3(2.5) Cisco Systems, Inc. www.cisco.com Cisco has more than 200 offices worldwide. Addresses, phone numbers, and fax numbers are listed on the Cisco website at www.cisco.com/go/offices. Open Source Used In Cisco Nexus 1000V Switch for VMware vSphere 5.2(1)SV3(2.5) 1 Text Part Number: 78EE117C99-136671678 Open Source Used In Cisco Nexus 1000V Switch for VMware vSphere 5.2(1)SV3(2.5) 2 This document contains licenses and notices for open source software used in this product. With respect to the free/open source software listed in this document, if you have any questions or wish to receive a copy of any source code to which you may be entitled under the applicable free/open source license(s) (such as the GNU Lesser/General Public License), please contact us at [email protected]. In your requests please include the following reference number 78EE117C99-136671678 Contents 1.1 .NET DiscUtils 0.10 1.1.1 Available under license 1.2 AES_MODES_SOURCE_CODE 23-07-09 1.2.1 Available under license 1.3 BOOST C++ Library 1.56.0 1.3.1 Available under license 1.4 cjson 2009 1.4.1 Available under license 1.5 expat 1.95.8 :3.0.0.0801182 1.5.1 Available under license 1.6 httpd 2.2.27 1.6.1 Available under license 1.7 IPNetwork Utility 1.3.1 1.7.1 Available under license 1.8 kernel-linux 2.6.27 1.8.1 Available under license 1.9 libaudiofile 0.2.4 :1.0.0.0501961 1.9.1 Available under license 1.10 libaudiofile - programs 0.2.4 :1.0.0.0501961 1.10.1 Available under license
    [Show full text]
  • Veritas Access Installation Guide
    Veritas Access Installation Guide Linux 7.4.2 September 2019 Veritas Access Installation Guide Last updated: 2019-09-30 Document version: 7.4.2 Rev 2 Legal Notice Copyright © 2018 Veritas Technologies LLC. All rights reserved. Veritas, the Veritas Logo, Veritas InfoScale, and NetBackup are trademarks or registered trademarks of Veritas Technologies LLC or its affiliates in the U.S. and other countries. Other names may be trademarks of their respective owners. This product may contain third-party software for which Veritas is required to provide attribution to the third party (“Third-Party Programs”). Some of the Third-Party Programs are available under open source or free software licenses. The License Agreement accompanying the Software does not alter any rights or obligations you may have under those open source or free software licenses. Refer to the third-party legal notices document accompanying this Veritas product or available at: https://www.veritas.com/licensing/process The product described in this document is distributed under licenses restricting its use, copying, distribution, and decompilation/reverse engineering. No part of this document may be reproduced in any form by any means without prior written authorization of Veritas Technologies LLC and its licensors, if any. THE DOCUMENTATION IS PROVIDED "AS IS" AND ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE DISCLAIMED, EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID. VERITAS TECHNOLOGIES LLC SHALL NOT BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, PERFORMANCE, OR USE OF THIS DOCUMENTATION.
    [Show full text]
  • Latest Result of DNSSEC Validation
    BIND 9 Administrator Reference Manual Internet Systems Consortium Sep 23, 2021 CONTENTS 1 Introduction 1 1.1 Scope of Document ............................................ 1 1.2 Organization of This Document ..................................... 1 1.3 Conventions Used in This Document ................................... 1 1.4 The Domain Name System (DNS) .................................... 2 2 BIND Resource Requirements 7 2.1 Hardware Requirements ......................................... 7 2.2 CPU Requirements ............................................ 7 2.3 Memory Requirements .......................................... 7 2.4 Name Server-Intensive Environment Issues ............................... 7 2.5 Supported Operating Systems ...................................... 8 3 Name Server Configuration 9 3.1 Sample Configurations .......................................... 9 3.2 Load Balancing .............................................. 10 3.3 Name Server Operations ......................................... 11 3.4 Plugins .................................................. 13 4 BIND 9 Configuration Reference 15 4.1 Configuration File Elements ....................................... 15 4.2 Configuration File Grammar ....................................... 18 4.3 Zone File ................................................. 105 4.4 BIND 9 Statistics ............................................. 110 5 Advanced DNS Features 117 5.1 Notify ................................................... 117 5.2 Dynamic Update ............................................
    [Show full text]