Lecture 10  80: Http  21: Ftp  23: Telnet Servers  22: Ssh February 4, 2005  79: Finger  42: Nameserver  13: Daytime  7: Echo  /Etc/Services

Total Page:16

File Type:pdf, Size:1020Kb

Lecture 10  80: Http  21: Ftp  23: Telnet Servers  22: Ssh February 4, 2005  79: Finger  42: Nameserver  13: Daytime  7: Echo  /Etc/Services Ports Some well-known ports: Lecture 10 80: http 21: ftp 23: telnet Servers 22: ssh February 4, 2005 79: finger 42: nameserver 13: daytime 7: echo /etc/services Telnet Protocol Telnet Protocol TELNET is a protocol that provides “a general, bi- TCP connection directional, eight-bit byte oriented communications Data and control over the same connection. facility”. Network Virtual Terminal telnet is a program that supports the TELNET Negotiated options protocol over TCP. Many application protocols are built upon the TELNET protocol. Network Virtual Terminal Network Virtual Terminal Intermediate representation of a generic terminal. Server Provides a standard language for Process communication of terminal control functions. Uses 7 bit codes for characters, transmitted as 8 bits (MSB=0). EOF is CR (carriage NVT NVT return) followed by LF (line feed). CR is CR TCP TCP followed by NUL (all bits zero) character. 1 Negotiable Options Negotiated Options All NVTs support a minimal set of The protocol for requesting optional features capabilities. is well defined and includes rules for Some terminals have more capabilities than eliminating possible negotiation “loops”. the minimal set. The set of options is not part of the TELNET The 2 endpoints negotiate a set of mutually protocol, so that new terminal features can acceptable options (character set, echo be incorporated without changing the mode, etc). TELNET protocol. Examples for Options EBDIC and ASCII ASCII: 7-bit character set, 8th bit can be Line mode vs. character mode used for error checking or extended characters. echo modes EBCDIC: IBM, 8-bit, no parity checking possible, more control characters. character set (EBCDIC vs. ASCII) Some Control Characters Command Structure Erase Character (EC): All TELNET commands and data flow delete last character sent through the same TCP connection. typically used to edit keyboard input Commands start with a special character called the Interpret as Command character (IAC). Erase Line (EL): The IAC code is 255. delete all input in current line If a 255 is sent as data - it must be followed by another 255. 2 Looking for Commands Command Codes Each receiver must look at each byte that IP 243 suspend, interrupt, abort process arrives and look for IAC. AO 244 abort output AYT 245 are you there If IAC is found and the next byte is IAC - a EC 246 erase character single byte is presented to the EL 247 erase line application/terminal (a 255). WILL 251 performing indicated option If IAC is followed by any other code - the WONT 252 refuse to perform option TELNET layer interprets this as a command. DO 253 request indicated option DONT 254 stop indicated option IAC 255 interpret as command Options Options Options are agreed on by a process of negotiation, Sender wants the other end to echo: option will affect interchange and operation of client and/or server. 255(IAC), 251(WILL), 1 Either end: IAC, <operation>, <option> Patterns: Final byte indicates option. Sender Receiver WILL DO sender wants option For some of the options values need to be WILL DONT sender wants option exchanged: sub-option negotiation: DO WILL sender requests option DO WONT sender requests option IAC, SB, <option>, 1, IAC, SE WONT DONT DONT is only valid response IAC, SB, <option>, 0, <value>, IAC, SE DONT WONT WONT is only valid response Options Playing with Telnet Example: client wishes to identify terminal You can use the telnet program to play type to the server: with the TELNET protocol. client 255(IAC), 251(WILL), 24 telnet is a generic TCP client. server 255(IAC), 253(DO), 24 Sends whatever you type to the TCP socket. server 255(IAC), 250(SB), 24, 1, 255(IAC), 240(SE) Prints whatever comes back through the TCP client 255(IAC), 250(SB), 24, 0, ‘V’, ‘T’, ‘2’, ‘2’, ‘0’, socket. 255(IAC), 240(SE) Useful for testing TCP servers (ASCII based protocols). 1: value required, 0: value supplied 3 Some TCP Servers you can play with telnet hostname port Some Unix systems have these servers > telnet cs.someschool.edu 7 running (by default): Trying 128.113.111.31... Connected to machine.cs.someschool.edu echo port 7 (128.113.112.31). discard port 9 Escape character is '^]'. daytime port 13 Hi dave Hi dave chargen port 19 stop it stop it ^] telnet> quit Connection closed. Playing with Telnet Telnet vs TCP Try this: Not all TCP servers talk TELNET (most don't) telnet telnet> toggle options Will show option processing. telnet> open machine.school.edu Trying 130.207.3.8... You can use the telnet program to play with these Connected to machine.school.edu (129.128.127.31). servers, but the fancy commands won't do anything. Escape character is ‘^]’. type ^], then "help" for a list of fancy TELNET stuff you can SENT DO ENCRYPT do in telnet. SENT WILL ENCRYPT SENT DO SUPPRESS GO AHEAD SENT WILL TERMINAL TYPE SENT WILL NAWS SENT WILL TSPEED ... Client/Server Web Server Basics telnet protocol and program. HTTP: HyperText Transfer Protocol now: web server example (Apache). (communication between web server and web browser). Request Response Web Browser Web Server (Mosaic) (Apache) 4 Apache Overview Apache 2.0 Parent Parent Child Child Child Child Child Child threads (“ThreadPerChild”) for requests and one listener thread Apache 2.0 Apache 2.0 Apache tries to maintain pool of spare server Typical configuration file: threads. “StartServers”: initally started processes. ServerLimit 16 Dynamically forks/kills processes to keep number of idle threads between “MinSpareThreads” and StartServers 2 “MaxSpareThreads”. MaxClients 150 “MaxClients”: max. number of child processes is MinSpareThreads 25 MaxClients/ThreadsPerChild. MaxSpareThreads 75 “ServerLimit”: hard limit for child processes. ThreadsPerChild 25 “ThreadLimit”: hard limit for threads. Apache 2.0 Apache 2.0 Modules: dynamic or static linkage Parent 100s of threads in-process modules: run from inside the httpd process (mod_cgi, mod_perl, mod_php, Tomcat mod_python, mod_tcl) out-of-process modules (mod_proxy, mod_jrun) Child Child Child … (10s) … (10s) DB mod_jk mod_rewrite mod_php mod_perl 5 Apache 2.0 Apache 2.0 Multi-Processing Module (MPM) Client: An MPM defines how the server will receive single HTTP connection (eg. web browser). and manage incoming requests. note that many web browsers open up multiple connections. Apache considers each connection Allows OS-specific optimizations. uniquely. Allows vastly different server models (eg. threaded vs. multiprocess). Apache 2.0 Performance: sendfile() Keepalive requests: fd-to-fd copying of data (stay in kernel). No more double-copy. Persistent connections Zero-copy*. multiple requests over one TCP socket Dramatic improvement for static files. Available on directives: Linux 2.4.x KeepAlive Solaris 8+ MaxKeepAliveRequests FreeBSD/NetBSD/OpenBSD KeepAliveTimeout ... * Zero-copy requires both OS support and NIC driver support. Web Server Performance Server ‘Quality’ ab Response time: flood server side: time to handle a request httperf client side: request transmission + time to handle a request + reply transmission JMeter Throughput: ...and many others number of requests handled in a second 6 Response Times Throughput ab flood Simple Load on a Single URL. Profile-driven load tester. Comes with Apache. Useful for generating real-world scenarios. Good for sanity check. Built to be highly-scalable. Scales poorly. Designed to be extremely flexible. JMeter Has a graphical interface. Built on Java. Part of Apache Jakarta (Java and Apache) project. Depends heavily on JVM performance. 7.
Recommended publications
  • Secure Shell Encrypt and Authenticate Remote Connections to Secure Applications and Data Across Open Networks
    Product overview OpenText Secure Shell Encrypt and authenticate remote connections to secure applications and data across open networks Comprehensive Data security is an ongoing concern for organizations. Sensitive, security across proprietary information must always be protected—at rest and networks in motion. The challenge for organizations that provide access to applications and data on host systems is keeping the data Support for Secure Shell (SSH) secure while enabling access from remote computers and devices, whether in a local or wide-area network. ™ Strong SSL/TLS OpenText Secure Shell is a comprehensive security solution that safeguards network ® encryption traffic, including internet communication, between host systems (mainframes, UNIX ™ servers and X Window System applications) and remote PCs and web browsers. When ™ ™ ™ ™ Powerful Kerberos included with OpenText Exceed or OpenText HostExplorer , it provides Secure Shell 2 (SSH-2), Secure Sockets Layer (SSL), LIPKEY and Kerberos security mechanisms to ensure authentication security for communication types, such as X11, NFS, terminal emulation (Telnet), FTP support and any TCP/IP protocol. Secure Shell encrypts data to meet the toughest standards and requirements, such as FIPS 140-2. ™ Secure Shell is an add-on product in the OpenText Connectivity suite, which encrypts application traffic across networks. It helps organizations achieve security compliance by providing Secure Shell (SSH) capabilities. Moreover, seamless integration with other products in the Connectivity suite means zero disruption to the users who remotely access data and applications from web browsers and desktop computers. Secure Shell provides support for the following standards-based security protocols: Secure Shell (SSH)—A transport protocol that allows users to log on to other computers over a network, execute commands on remote machines and securely move files from one machine to another.
    [Show full text]
  • Secure Telnet
    The following paper was originally published in the Proceedings of the Fifth USENIX UNIX Security Symposium Salt Lake City, Utah, June 1995. STEL: Secure TELnet David Vincenzetti, Stefano Taino, and Fabio Bolognesi Computer Emergency Resource Team Italy Department of Computer Science University of Milan, Italy For more information about USENIX Association contact: 1. Phone: 510 528-8649 2. FAX: 510 548-5738 3. Email: [email protected] 4. WWW URL: http://www.usenix.org STEL Secure TELnet David Vincenzetti Stefano Taino Fabio Bolognesi fvince k taino k b ologdsiunimiit CERTIT Computer Emergency Response Team ITaly Department of Computer Science University of Milan ITALY June Abstract Eavesdropping is b ecoming rampant on the Internet We as CERTIT have recorded a great numb er of sning attacks in the Italian community In fact sning is the most p opular hackers attack technique all over the Internet This pap er presents a secure telnet implementation whichhas b een designed by the Italian CERT to makeeavesdropping ineective to remote terminal sessions It is not to b e considered as a denitive solution but rather as a bandaid solution to deal with one of the most serious security threats of the moment Intro duction STEL stands for Secure TELnet We started developing STEL at the University of Milan when we realized that eavesdropping was a very serious problem and we did not like the freeware solutions that were available at that time It was ab out three years ago Still as far as we know e tapping problem and there are no really satisfying
    [Show full text]
  • Telnet Client 5.11 Ssh Support
    TELNET CLIENT 5.11 SSH SUPPORT This document provides This document describes how to install and configure SSH support in Wavelink Telnet Client 5.11. information on the SSH support available in Telnet Client 5.11 OVERVIEW OF SSH SUPPORT Secure Shell (SSH) is a protocol developed for transmitting private information over the Internet. SSH OVERVIEW encrypts data that is transferred over the Telnet session. • Overview of SSH The Telnet Client supports SSH version 1 and 2 and will automatically select the most secure protocol Support that the SSH server supports. • Installing Windows SSH Support This document describes the following: • Configuring the host • Installing Windows SSH support utility profile for SSH • Configuring the host profile for SSH support support • Deploying Windows • Deploying Windows SSH support to the device through Avalanche or ActiveSync SSH Support • Revision History INSTALLING WINDOWS SSH SUPPORT Installing SSH support is a two-step process. First, install SSH support on the PC from which you will deploy Telnet. Once you install SSH support on the PC, use Avalanche or ActiveSync to deploy the utility to the device. To install SSH support on your PC: 1. Obtain the installation executable for SSH support. NOTE: To obtain the Wavelink SSH support utility install, go to http://www.wavelink.com/downloads/ files/sshagreement.aspx. 2. Install SSH support on the PC from which you will deploy the Telnet Client. CONFIGURING THE HOST PROFILE FOR SSH SUPPORT SSH support is configured from the Host Profiles window of the configuration utility. NOTE: SSH is only an active option if SSH support has been installed on the PC running the Telnet Client configuration utility.
    [Show full text]
  • Cheat Sheet – Common Ports (PDF)
    COMMON PORTS packetlife.net TCP/UDP Port Numbers 7 Echo 554 RTSP 2745 Bagle.H 6891-6901 Windows Live 19 Chargen 546-547 DHCPv6 2967 Symantec AV 6970 Quicktime 20-21 FTP 560 rmonitor 3050 Interbase DB 7212 GhostSurf 22 SSH/SCP 563 NNTP over SSL 3074 XBOX Live 7648-7649 CU-SeeMe 23 Telnet 587 SMTP 3124 HTTP Proxy 8000 Internet Radio 25 SMTP 591 FileMaker 3127 MyDoom 8080 HTTP Proxy 42 WINS Replication 593 Microsoft DCOM 3128 HTTP Proxy 8086-8087 Kaspersky AV 43 WHOIS 631 Internet Printing 3222 GLBP 8118 Privoxy 49 TACACS 636 LDAP over SSL 3260 iSCSI Target 8200 VMware Server 53 DNS 639 MSDP (PIM) 3306 MySQL 8500 Adobe ColdFusion 67-68 DHCP/BOOTP 646 LDP (MPLS) 3389 Terminal Server 8767 TeamSpeak 69 TFTP 691 MS Exchange 3689 iTunes 8866 Bagle.B 70 Gopher 860 iSCSI 3690 Subversion 9100 HP JetDirect 79 Finger 873 rsync 3724 World of Warcraft 9101-9103 Bacula 80 HTTP 902 VMware Server 3784-3785 Ventrilo 9119 MXit 88 Kerberos 989-990 FTP over SSL 4333 mSQL 9800 WebDAV 102 MS Exchange 993 IMAP4 over SSL 4444 Blaster 9898 Dabber 110 POP3 995 POP3 over SSL 4664 Google Desktop 9988 Rbot/Spybot 113 Ident 1025 Microsoft RPC 4672 eMule 9999 Urchin 119 NNTP (Usenet) 1026-1029 Windows Messenger 4899 Radmin 10000 Webmin 123 NTP 1080 SOCKS Proxy 5000 UPnP 10000 BackupExec 135 Microsoft RPC 1080 MyDoom 5001 Slingbox 10113-10116 NetIQ 137-139 NetBIOS 1194 OpenVPN 5001 iperf 11371 OpenPGP 143 IMAP4 1214 Kazaa 5004-5005 RTP 12035-12036 Second Life 161-162 SNMP 1241 Nessus 5050 Yahoo! Messenger 12345 NetBus 177 XDMCP 1311 Dell OpenManage 5060 SIP 13720-13721
    [Show full text]
  • TCP/IP Standard Applications Telnet - SSH - FTP - SMTP - HTTP
    TCP/IP Standard Applications Telnet - SSH - FTP - SMTP - HTTP Virtual Terminal, Secure Shell, File Transfer, Email, WWW Agenda • Telnet (Virtual Terminal) • SSH • FTP (File Transfer) • E-Mail and SMTP • WWW and HTTP © 2016, D.I. Lindner / D.I. Haas Telnet-SSH-FTP-SMTP-HTTP, v6.0 2 What is Telnet? • Telnet is a standard method to communicate with another Internet host • Telnet provides a standard interface for terminal devices and terminal-oriented processes through a network • using the Telnet protocol user on a local host can remote-login and execute commands on another distant host • Telnet employs a client-server model – a Telnet client "looks and feels" like a Terminal on a distant server – even today Telnet provides a text-based user interface © 2016, D.I. Lindner / D.I. Haas Telnet-SSH-FTP-SMTP-HTTP, v6.0 3 Local and Remote Terminals network local terminal workstation Host as remote terminal with Telnet Server with Telnet Client traditional configuration today's demand: remote login © 2016, D.I. Lindner / D.I. Haas Telnet-SSH-FTP-SMTP-HTTP, v6.0 4 About Telnet • Telnet was one of the first Internet applications – since the earliest demand was to connect terminals to hosts across networks • Telnet is one of the most popular Internet applications because – of its flexibility (checking E-Mails, etc.) – it does not waste much network resources – because Telnet clients are integrated in every UNIX environment (and other operating systems) © 2016, D.I. Lindner / D.I. Haas Telnet-SSH-FTP-SMTP-HTTP, v6.0 5 Telnet Basics • Telnet is connection oriented and uses the TCP protocol • clients connect to the "well-known" destination port 23 on the server side • protocol specification: RFC 854 • three main ideas: – concept of Network Virtual Terminals (NVTs) – principle of negotiated options – a symmetric view of terminals and (server-) processes © 2016, D.I.
    [Show full text]
  • Secure Shell- Its Significance in Networking (Ssh)
    International Journal of Application or Innovation in Engineering & Management (IJAIEM) Web Site: www.ijaiem.org Email: [email protected] Volume 4, Issue 3, March 2015 ISSN 2319 - 4847 SECURE SHELL- ITS SIGNIFICANCE IN NETWORKING (SSH) ANOOSHA GARIMELLA , D.RAKESH KUMAR 1. B. TECH, COMPUTER SCIENCE AND ENGINEERING Student, 3rd year-2nd Semester GITAM UNIVERSITY Visakhapatnam, Andhra Pradesh India 2.Assistant Professor Computer Science and Engineering GITAM UNIVERSITY Visakhapatnam, Andhra Pradesh India ABSTRACT This paper is focused on the evolution of SSH, the need for SSH, working of SSH, its major components and features of SSH. As the number of users over the Internet is increasing, there is a greater threat of your data being vulnerable. Secure Shell (SSH) Protocol provides a secure method for remote login and other secure network services over an insecure network. The SSH protocol has been designed to support many features along with proper security. This architecture with the help of its inbuilt layers which are independent of each other provides user authentication, integrity, and confidentiality, connection- oriented end to end delivery, multiplexes encrypted tunnel into several logical channels, provides datagram delivery across multiple networks and may optionally provide compression. Here, we have also described in detail what every layer of the architecture does along with the connection establishment. Some of the threats which Ssh can encounter, applications, advantages and disadvantages have also been mentioned in this document. Keywords: SSH, Cryptography, Port Forwarding, Secure SSH Tunnel, Key Exchange, IP spoofing, Connection- Hijacking. 1. INTRODUCTION SSH Secure Shell was first created in 1995 by Tatu Ylonen with the release of version 1.0 of SSH Secure Shell and the Internet Draft “The SSH Secure Shell Remote Login Protocol”.
    [Show full text]
  • Networking Telnet
    IBM i Version 7.2 Networking Telnet IBM Note Before using this information and the product it supports, read the information in “Notices” on page 99. This edition applies to IBM i 7.2 (product number 5770-SS1) and to all subsequent releases and modifications until otherwise indicated in new editions. This version does not run on all reduced instruction set computer (RISC) models nor does it run on CISC models. This document may contain references to Licensed Internal Code. Licensed Internal Code is Machine Code and is licensed to you under the terms of the IBM License Agreement for Machine Code. © Copyright International Business Machines Corporation 1998, 2013. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Telnet................................................................................................................... 1 What's new for IBM i 7.2..............................................................................................................................1 PDF file for Telnet........................................................................................................................................ 1 Telnet scenarios...........................................................................................................................................2 Telnet scenario: Telnet server configuration.........................................................................................2 Telnet scenario: Cascaded Telnet
    [Show full text]
  • NCSA Telnet for the Macintosh User's Guide
    NCSA Telnet for the Macintosh User’s Guide Version 2.6 • October 1994 National Center for Supercomputing Applications University of Illinois at Urbana-Champaign Contents Introduction Features of NCSA Telnet v Differences between Version 2.5 and Version 2.6 v New Features in Version 2.6 v Discontinued Features vi Bugs Fixed from Version 2.5 vi System Requirements vi Notational Conventions vi 1 Getting Started Installation Note 1-1 Beginning an NCSA Telnet Session 1-1 Opening and Closing a Connection 1-2 Opening a Connection 1-2 Logging on to Your Host 1-3 Setting the BACKSPACE/DELETE Key 1-3 Setting a VT Terminal Type 1-3 Emulating the VT Terminal Keyboard 1-4 Closing a Connection 1-4 Copying, Pasting, and Printing 1-5 Copy and Paste from the Edit Menu 1-5 Print from the File Menu 1-5 Ending an NCSA Telnet Session 1-6 2 Configuration Global Preferences 2-1 New Configuration System in Version 2.6 2-3 Default Configuration Records 2-3 Editing Configuration Records 2-3 Editing Terminal Configuration Records 2-4 Editing Session Configuration Records 2-5 Changing Configuration after Session Connected 2-9 Saved Sets 2-13 Saving a Set 2-14 Using a Saved Set 2-14 Loading a Saved Set 2-15 Macro Definitions 2-15 Reverting to Previous Macro Definitions 2-16 Saving Macros 2-16 3 Advanced Features Cursor Positioning with the Mouse 3-1 Multiple Connections 3-1 Opening More Than One Connection 3-1 Moving between Connections 3-1 Rules for Session Names 3-2 The Connections Menu 3-2 Naming Windows 3-2 Checking Session Status 3-2 Aborting Connection Attempts
    [Show full text]
  • Chapter 7, “Configuring Telnet”
    Send document comments to [email protected]. CHAPTER 7 Configuring Telnet This chapter describes how to configure Telnet on Nexus 1000V and includes the following topics: • Information About the Telnet Server, page 7-1 • Prerequisites for Telnet, page 7-1 • Guidelines and Limitations, page 7-2 • Configuring Telnet, page 7-2 • Verifying the Telnet Configuration, page 7-5 • Default Setting, page 7-5 • Additional References, page 7-5 • Feature History for Telnet, page 7-6 Information About the Telnet Server The Telnet protocol enables you to set up TCP/IP connections to a host. Telnet allows a person at one site to establish a TCP connection to a login server at another site and then passes the keystrokes from one device to the other. Telnet can accept either an IP address or a domain name as the remote device address. Note On Nexus 1000V, the Telnet server is enabled by default. Prerequisites for Telnet Telnet has the following prerequisites: • You have configured IP on a Layer 3 interface, out-of-band on the mgmt 0 interface, or inband on an Ethernet interface. Cisco Nexus 1000V Security Configuration Guide, Release 4.0(4)SV1(1) OL-19418-01 7-1 Chapter 7 Configuring Telnet Guidelines and Limitations Send document comments to [email protected]. Guidelines and Limitations • By default, the Telnet server is enabled. Note Be aware that the Nexus 1000V commands might differ from the Cisco IOS commands. Configuring Telnet This section includes the following topics: • Enabling the Telnet Server, page 7-2 • Starting an IP Telnet Session to a Remote Device, page 7-3 • Clearing Telnet Sessions, page 7-4 Enabling the Telnet Server Use this procedure to enable the Telnet server.
    [Show full text]
  • Configuring SSH and Telnet
    Configuring SSH and Telnet This chapter describes how to configure Secure Shell Protocol (SSH) and Telnet on Cisco NX-OS devices. This chapter includes the following sections: • About SSH and Telnet, on page 1 • Licensing Requirements for SSH and Telnet, on page 3 • Prerequisites for SSH and Telnet, on page 3 • Guidelines and Limitations for SSH and Telnet, on page 3 • Default Settings for SSH and Telnet, on page 4 • Configuring SSH , on page 4 • Configuring Telnet, on page 15 • Verifying the SSH and Telnet Configuration, on page 17 • Configuration Example for SSH, on page 18 • Configuration Example for SSH Passwordless File Copy, on page 19 • Additional References for SSH and Telnet, on page 21 About SSH and Telnet This section includes information about SSH and Telnet. SSH Server You can use the SSH server to enable an SSH client to make a secure, encrypted connection to a Cisco NX-OS device. SSH uses strong encryption for authentication. The SSH server in the Cisco NX-OS software can interoperate with publicly and commercially available SSH clients. The user authentication mechanisms supported for SSH are RADIUS, TACACS+, LDAP, and the use of locally stored usernames and passwords. SSH Client The SSH client feature is an application that runs over the SSH protocol to provide device authentication and encryption. The SSH client enables a Cisco NX-OS device to make a secure, encrypted connection to another Cisco NX-OS device or to any other device that runs the SSH server. This connection provides an outbound Configuring SSH and Telnet 1 Configuring SSH and Telnet SSH Server Keys connection that is encrypted.
    [Show full text]
  • Secure Shell Refers to a Protocol Or Method That Allows One Computer to Access Another Computer Across a Network in a Very Secure Manner
    This material is based on work supported by the National Science Foundation under Grant No. 0802551 Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author (s) and do not necessarily reflect the views of the National Science Foundation C2L7S1 Secure shell refers to a protocol or method that allows one computer to access another computer across a network in a very secure manner. In this lesson, you will explore secure encrypted Internet sessions, and you will learn how to configure OpenSSH—a favorite tool used for Secure Shell sessions. Additionally, you will explore the different options available to you through SSH connections. U the This lesson is part of the Linux administration course. Secure Shell is an important topic because Linux administrators and other employees often need to access business computers remotely, and they must be trained to establish such access in a secure manner to prevent or minimize data loss, network vulnerabilities, or infiltration by unauthorized users. C2L7S2 Student Expectations You should know what will be expected of you when you complete this lesson. These expectations are presented as objectives. Objectives are short statements of expectations that tell you what you must be able to do, perform, learn, or adjust after reviewing the lesson. C2L7S3 Objective Given a need to secure Internet transmissions, the student will be able to describe the importance of tools such as SSH and configure OpenSSH for secure transmission as per industry standards. C2L7S4 In this lesson, you will explore: • Important terms related to SSH • Installing OpenSSH on Ubuntu • Installing OpenSSH on Fedora • Configuring SSH server • Creating public and private keys • SSH Tunneling C2L7S5 The company for which you work as a Linux administrator is small.
    [Show full text]
  • CS for Z/OS V1R8 TCP/IP Implementation
    Front cover Communications Server for z/OS V1R8 TCP/IP Implementation Volume 2: Standard Applications Understand important CS for z/OS TCP/IP standard applications See TCP/IP standard application implementation examples Leverage TCP/IP standard applications for your needs Bill White Adi Horowitz Yukihiko Miyamoto Gilson Cesar de Oliveira Roland Peschke ibm.com/redbooks International Technical Support Organization Communications Server for z/OS V1R8 TCP/IP Implementation Volume 2: Standard Applications December 2006 SG24-7340-00 Note: Before using this information and the product it supports, read the information in “Notices” on page ix. First Edition (December 2006) This edition applies to Version 1, Release 8 of Communications Server for z/OS. © Copyright International Business Machines Corporation 2006. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Notices . ix Trademarks . .x Preface . xi Our implementation environment . xi The environment used for all four books. xi Our focus for this book . xiii The team that wrote this redbook. xiii Become a published author . xiv Comments welcome. xiv Chapter 1. TN3270E Telnet server . 1 1.1 Overview . 2 1.1.1 Basic concepts of TN3270 . 3 1.1.2 Additional information sources . 3 1.2 Why TN3270 is important . 4 1.2.1 TN3270E functionality. 4 1.2.2 Connection security . 5 1.2.3 Connection mapping . 6 1.2.4 Connection and session management . 6 1.2.5 Connection diagnostics. 6 1.3 The common design scenarios for TN3270 . 7 1.3.1 Telnet server executing within the TCP/IP address space .
    [Show full text]