User Manual

Contents
iii
5.4 Increasing Performance ..............................................................................................................5-9
5.4.1 Filtering Unwanted Data.............................................................................................5-9
5.4.2 Compressing Data and Correcting Errors...................................................................5-9
5.4.3 Adding Bandwidth......................................................................................................5-9
5.4.4 IP Header Compression ............................................................................................5-10
5.5 Reducing Cost...........................................................................................................................5-10
5.5.1 Inactivity Logouts.....................................................................................................5-10
5.5.2 Restricting Packets with Startup Filters....................................................................5-10
5.5.3 Reducing the Number of Ports Used ........................................................................5-11
5.5.4 Using Higher Speed Modems...................................................................................5-11
5.5.5 Restricting Connections to Particular Times ............................................................5-11
5.5.6 Increasing Requirements for Adding Additional Bandwidth ...................................5-12
5.5.7 Controlling Frequency of Calls.................................................................................5-12
5.6 Using the SCS Without Dialup Modems..................................................................................5-13
5.6.1 Situations Where Dialup Modems Are Not Used.....................................................5-13
5.6.2 Configuring the Unit for Modemless Connections...................................................5-14
5.7 Examples...................................................................................................................................5-15
5.7.1 Creating a Chat Script...............................................................................................5-15
5.7.2 Creating a Simple Firewall .......................................................................................5-16
5.7.3 Controlling Access During Weekend Hours ............................................................5-16
6: IP .............................................................................................................................. 6-1
6.1 IP Addresses................................................................................................................................6-1
6.1.1 IP Addresses for Incoming Connections ....................................................................6-2
6.1.2 IP Addresses For Outgoing Connections....................................................................6-4
6.2 Subnet Masks..............................................................................................................................6-5
6.2.1 Length of Subnet Masks .............................................................................................6-6
6.3 Name Resolving..........................................................................................................................6-6
6.3.1 Configuring the Domain Name Service (DNS)..........................................................6-7
6.3.2 Specifying a Default Domain Name...........................................................................6-7
6.3.3 Adding Hosts to the Host Table..................................................................................6-7
6.4 Header Compression...................................................................................................................6-8
6.5 Establishing Sessions..................................................................................................................6-8
6.5.1 Telnet and Rlogin Sessions.........................................................................................6-9
6.5.2 SSH Sessions ............................................................................................................6-10
6.6 IP Security.................................................................................................................................6-14
6.6.1 Configuring the Security Table.................................................................................6-14
6.6.2 Clearing Table Entries ..............................................................................................6-15
6.7 IP Routing .................................................................................................................................6-15
6.7.1 How Packets are Routed ...........................................................................................6-16
6.7.2 Routing Tables..........................................................................................................6-16
6.7.3 Using RIP..................................................................................................................6-18
6.7.4 Proxy ARP ................................................................................................................6-18
6.7.5 Using the NetBIOS Nameserver (NBNS) ................................................................6-19
6.7.6 Routing and Subnetworks.........................................................................................6-19
6.8 Displaying the IP Configuration ...............................................................................................6-20
6.9 Examples...................................................................................................................................6-22
6.9.1 IP Address Assignment for Remote Networking .....................................................6-22
6.9.2 General IP Setup ......................................................................................................6-23
6.9.3 Adding Static Routes ................................................................................................6-23
6.9.4 Default Routes to a Site ............................................................................................6-23