Mtu, PPP Async Map | USRobotics NETServer/16, NETServer/8 instruction

MTU

This is the Maximum Transmission Unit (MTU) used with this interface. MTU sets the largest frame or packet size that a connection protocol will send. If an IP packet’s size is greater than the MTU setting, it’s broken down into smaller pieces. IPX packets larger than the MTU are discarded. Use the following command:

set location <location name> mtu <value>

For IPX connections, the MTU must be set to 1500.

PPPconnections are set between 100 and 1500 (default is 1500). Note that either end of a PPP connection can negotiate for a smaller MTU if necessary. SLIP connections are set between 100 and 1006 (default is 1006).

PPPAsync Map

The PPP protocol supports the escaping of non-printing ASCII characters. Escaping means that specific characters won’t be sent, but will be replaced by a special set of characters. The remote site then interprets this special set of characters as the original characters.

The PPP Async Map is a bit-map of the 32ASCII control charac- ters (the first 32 characters of the ASCII character set), repre- sented as 8 hexadecimal digits. The order is actually big endian, which means that the last bit of the last character corresponds to the first ASCII character (Null) and so on. Use the following command:

set location <location name> map <value>

For example, to escape the ASCII null character to a location named Chicago the command would be

set location Chicago map 00000001

The default is 00000000 (do not escape any characters). We recommend that you do not change this field unless specifically required by your network.

Command Reference 10-21

Image 171

USRobotics NETServer/16, NETServer/8 manual Mtu, PPP Async Map

Contents

NETServer/8 NETServer/16 Page Table of Contents Network Dial-in Access Reference Section Administrative Tools Limited Warranty Warranty and Service Service and Support Technical SupportVii Viii We welcome your suggestions for better documentation Overview Chapter OverviewWhat’s New with Release 3.1? Additional Software Enhancements Accounting Server Support Netmask TableIP Address Spoofing Accounting Servers Icmp Message Logging Multiple Name ServersRandomized Hosts Radius Accounting and ANI/DNIS New Modem Port Features NETServer Overview IP Modem Sharing How do I get there from here? Security Administrative Utilities Chapter Basic Installation System Administrator RequirementsBasic Installation TCP/IP Reference Material Accessing the Command Line Getting Started First step for IPX or IP/IPX networks Getting the LAN port up and running Basic Installation IP Configuration You must also set the Broadcast Address. Type the following Ethernet802.3 ethernet802.2 ethernet802.2II ethernetII IPX Configuration Final Steps Recommended Global Configuration PasswordIP and IPX Default Gateways To set the IP gateway, type the following Save your work Name Service Basic Installation Chapter Configuration Overview How to Setup ApplicationsConfiguration Overview Application Section Where do I go from here? Separate a parameter and its value by a space Command LineCommands are not case sensitive You can abbreviate commands Save your changes Reset any ports you have changedReboot when necessary How to log out of the command line Quick Command Overview Overview of configurable tables Global ConfigurationHosts Table Netmasks Table Initialization Script ConfigurationNet0 LAN Port Configuration Location Table Packet Filter Table Port Type Port Configuration Routes Table Snmp Configuration User Table Configuration Overview Chapter IP Terminal Server Setup Terminal or Workstation SetupIP Terminal Server Setup NETServer Terminal Server Setup Overview Port Default Global DefaultUser Table Set the port’s security Pass-Thru Login Terminal Server Detailed SetupConfiguring a Port Set the port type to User Login Create default user settings for the port Port Default Login Service Optional Friendly Stuff Save sport # Configure the user Adding a Remote User to the User TableAdd the user to the User Table Login Service Configure for dialback use? Example IP Terminal Server Case Studies NETServer will use ports 6, 7, and 8 for this application Save your work and reset all the ports Example IP Terminal Server Setup Chapter Network Dial In Access Dial-in User SetupNetwork Dial In Access Prework NETServer Setup for Network Dial-In Overview Configuration NETServer Dial-In Detailed Setup Dialback Users on this Port? Save the changes to flash memory Normal or dialback user? Create a new user Add configuration information for the user This is the user’s IP subnet mask. Use the following command Option can be any one of the following Configure the ports IP Remote Access Case Study Create a user table entry for the dialback user Create user table entries for the dial in users Save your work and reset the ports Connecting to the NETServer IPX Remote Access Create User Table entries for the dial in users Setup for NETServer Routing Overview Chapter LAN-to-LAN RoutingLAN-to-LAN Routing IPX routing LAN-to-LAN Routing NETServer Routing An Introduction to NETServer Routing LAN-to-LAN Routing How RIP Dynamically Builds the Routing Table Static vs. Dynamic Routes Establishing Connections to Remote Gateways How Packets are Routed Routing Procedure PAP Password Authentication Protocol PAP/CHAP Authentication Chap Setup for the NETServer Chap Challenge Example Configuring the Port LAN-to-LAN Routing Detailed Setup Creating a Dial-Out Group Adding a Remote Device to the Location Table Create a new location table entrySet Required Location Parameters This is the remote device’s IP address Set location location name netmask netmask Dial Group Number Multiple lines for a single connection Maximum Ports Create a Dial Script Set location Chicago script 1 atds slot#\r Connect Adding the Remote Device to the User Table Create a User Table EntryTell the NETServer about the Remote Device Set user user name protocol ppp slip Set netuser user name compression on off LAN-to-LAN Routing Case Study Add netuser nsb password xyzabc Setting Up NETServer a Setting Up NETServer B Now, save your work and reset the ports Testing the Connection What If I Don’t Want to Use Chap Authentication? Connecting to NETServer a from NETServer B Assign the modem a TCP port number Configure the port as a host deviceChapter Talking to the Modems TCP/IP Modem Sharing Turn modem control carrier detect off Save your work and reset the port Implementing Security with Host Device Dial Out Configuring modems as Unix pseudo TTYs Talking to the Modems Assign Text to an Initialization Script Modem Initialization ScriptsHow To Add a New Initialization Script Use an Existing Initialization Script Delete an Initialization ScriptDisplaying an Initialization Script Initialization Script Example Default initialization string Sending AT commands to the modems Talking to the Modems Chapter Packet Filters Packet FiltersPacket Filters Packet Filters and the NETServer Types of Filters Information Sources Input filters vs. Output filters Adding Packet Filters Input filters vs. Output filters Filter Rule Format Rule TypeName Rule Number Permit or DenyOptions TCP/IP packet filtering Destination Address TCP and UDP parameters TCP UDP Standard Port Numbers FTP Packet Filtering Filtering RIP messages Client opens a control channel FTP Example Type Description Filtering Icmp packets IPX Rules IPX packet filtering Dsthost SAP Rule Options Delete a Packet Filter Editing Packet FiltersEdit a Packet Filter Delete a Packet Filter Rule View the Packet Filter Table View a Packet Filter Root Access Chapter Administrative ToolsConfiguring the !root account Changing the command prompt Telnet Access Port Manually Connecting to a Remote Site Dial CommandNslogin, Rlogin and Telnet Commands Viewing Debug messages Troubleshooting Commands Turn off the output console by typing the following Ifconfig MTU Ping Ptrace Version Traceroute Show Show command Show flash Show arp Show netconns Show memory Show netstat Show sessions Show sap Administrative Tools Chapter Command Reference Global ConfigurationCommand Reference View the Global Configuration Table Get helpSave Changes Connect Message Default HostGlobal user parameters Assigned Address Randomize Hosts Global routing parameters Default Gateways IP Address Spoofing Default Route System Name NetBIOS Packet PropagationPAP Authentication Proxy ARP Name Service ServiceServer name Domain name DNS Cache Reset Time-out Radius Secret Radius securityPrimary Radius Server Alternate Radius Server Syslog Accounting Radius Accounting Icmp Logging View the Hosts Table Hosts TableAdd a Host Delete a Host Change a Location’s Parameters Bring Up the List of CommandsLocation Table Add a Location to the Location Table Save Location Table Changes View the Location TableView a Particular Location Connection Type Location Table Parameters IP Address NetmaskIPX Network Protocol RoutingCompression Maximum Ports Dial Group High Water Mark Idle Time-out PPP Async Map MTU Output Filter Input FilterDial Script Send Reply Reset the Network Interface Card LAN Port Net0 Configuration View LAN Port Configuration LAN Port ParametersEthernet Status Interface Address Configured Ethernet Media Broadcast Address IPX Frame Type Set net0 ifilter filter name View the netmask table Netmask TableAdd a netmask Delete a netmask Change a Port’s Parameters Save Port Configuration View the Ports Table To view all of the S-ports, use the following command Idle Port is idle View an Individual Port User Login Determining a Port’s TypeHost Device Device Service Network Login Message Dial In Port ParametersLine Hangup Security Pass-Thru Login Login Prompt User Login Port Parameters Dialback DelayAutolog Name Host Login Service Terminal Type IPX Network Number Hardwired Port Parameters Set s0 netmask netmask NETServer sends RIP information across Stopbits Serial Communications ParametersPort Speed Databits Modem Control ParityFlow Control Host Override Routes Table Configuration Add a Route to the Routes TableChange a Route’s Information Delete a Routes Table Entry Save Routes Table ChangesView the IP Routes Table Flag Parameter Viewing the IPX Routes Table IP Parameters IPX Parameters Enabling/Disabling Snmp Snmp TableDelete Snmp Hosts Save the Snmp Table Changes Write Community Name Snmp Table ParametersView Snmp Table Read Community Name Write Hosts Read Hosts Add a User to the User Table User Table View the User Table Change a User’s ParametersDelete a User Save User Table Changes Login User Parameters Access FilterDialback Number Set user name service rlogin telnet netdata portmux Command Reference Dialback Network User Parameters IPX connections require the PPP protocol NETServer sends RIP information to the dial Set user filter name ofilter filter name Command Reference 16 port NETServer Hardware Appendix a Technical Specifications Typical Input Power Power RequirementsMaximum Output Power Maximum Input Power External Serial Port Console Technical Specifications A-3 10Base-T Ethernet Network Interface Card Isolated GND SignalTechnical Specifications A-5 10Base-2 BNC Technical Specifications Token Ring⎯STP Connector Technical Specifications A-7Token Ring Network Interface Card Token Ring⎯UTP Connector Routing Support NETServer Firmware SpecificationsAdministration Technical Specifications A-9 PPP Specific Features Industry Standards SupportClient Dial-up Support Slip and PPP Client Software Support Technical Specifications A-11 Technical Specifications Addressing Schemes B-1 Appendix B Addressing SchemesIPX Addressing Basics IP Addressing Basics Address Classes SubnettingAddressing Schemes Addressing Schemes B-3 Mask Binary Subnets Hosts Reserved Addresses Addressing Schemes B-5 Supernetting Advanced TCP/IP Cidr Each Supernet is treated as a single entity Addressing Schemes B-7 Step two Select a range of addresses for each supernet Addressing Schemes B-9 Supernetting and the NETServer Software Download C-1 SDL Using a Direct Connection to a PCWhy Perform an SDL Software Download? Appendix C Software Download Starting SDL Make Backup Copies of the NETServer FirmwareSoftware Installation Loading the Software Download SDL Program Software Download C-3 SDL Command Syntax Filename Prefixes Optional -d Parameter Software Download C-5 Entering SDL Mode Upgrading NETServer Firmware From the Windows Management Software Software Download C-7 Upgrading the Modem Firmware For the Isdn NETServer, the file names are Software Download C-9 Error Messages PC SDL program detected unknown command line argu- ments Software Download C-11 Invalid Control Word Software Download C-13 File you are trying to download is not a NETServer file Boot Process D-1 Appendix D Boot Process Boot Process Using Syslog Appendix E Syslog AccountingSyslog Accounting E-1 Syslog Accounting Syslog System MessagesSpotting Unused Ports Syslog System Message Format Syslog Accounting E-3 Syslog System Message Examples Someone has logged in as !root on port S16 Syslog Accounting E-5 Syslog Accounting Obtaining Radius Appendix F Security a Centrally Managed User Table Authentication Items Setting Up Radius User Table Entries Response Items Radius F-5 Framed-Netmask Radius F-7 User Types Radius F-9 Making NETServer talk to a Radius security server Chap authentication using Radius Acct-Status-Type Acct-Delay-TimeRadius Accounting Radius accounting fields Accounting Examples Acct-AuthenticAcct-Session-Time Radius Index Alphabetical Index Index Icmp MTU NIC PPP SAP Slip Index Index