Router User's Guide
Table Of Contents
- Contents
- About This Guide
- 1. About the FrameSaver SLV
- 2. User Interface and Basic Operation
- 3. Configuration Procedures
- 4. Configuration Options
- Using the Easy Install Feature
- Using RIP with FrameSaver SLV CSU/DSUs
- Entering System Information and Setting the System Clock
- Setting Up the Modem
- Setting Up Auto-Configuration
- Setting Up Dial Backup
- PVC Backup Over the Network Interface
- Setting Up Back-to-Back Operation
- Configuration Option Tables
- Configuring the Overall System
- Configuring Physical Interfaces
- Assigning Time Slots/Cross Connections
- Configuring Frame Relay for an Interface
- Manually Configuring DLCI Records
- Configuring PVC Connections
- Configuring the IP Path List
- Setting Up Management and Communication Options
- Configuring the Criteria for Automatic Backup
- 5. Configuring the FrameSaver SLV Router
- FrameSaver SLV Router Overview
- IP Routing
- Address Resolution Protocol
- Proxy ARP
- Interface Configuration
- Network Address Translation
- Network Address Port Translation
- Dynamic Host Configuration Protocol Server
- DHCP Relay Agent
- Router Security
- Provisioning the Router Interface
- Configuring the Router Using Terminal Emulation
- 6. Security and Logins
- 7. Operation and Maintenance
- 8. Troubleshooting
- 9. Setting Up OpenLane for FrameSaver Devices and Activating SLM Features
- 10. Setting Up NetScout Manager Plus for FrameSaver Devices
- 11. Setting Up Network Health for FrameSaver Devices
- A. Menu Hierarchy
- B. SNMP MIBs and Traps, and RMON Alarm Defaults
- C. Router CLI Commands, Codes, and Designations
- D. Router Command Line Summaries and Shortcuts
- E. Connectors, Cables, and Pin Assignments
- F. Technical Specifications
- G. Equipment List
- Index
5. Configuring the FrameSaver SLV Router
9128-A2-GB20-80 September 2002
5-5
Network Address Translation
Network Address Translation (NAT) is used when a private network’s internal IP
addresses cannot be used outside the private network. IP addresses may be
restricted for privacy reasons, or they may not be valid public IP addresses.
The router provides NAT as described in RFC 1631,
The
IP Network Address
Translator (NAT).
NAT allows hosts in a private (local) network to transparently
access the external (public or global) network by using a block of public addresses.
Static mapping enables access to selected local hosts from the outside using
these external IP addresses.
Traditional NAT and Network Address Port Translation (NAPT) are supported.
When both NAT and NAPT are enabled, one-to-one NAT mapping is performed by
translating a range of assigned public IP addresses to a similar-sized pool of
private addresses, followed by many-to-one NAPT bindings. Up to 254 IP
addresses can be allocated for NAT usage.
IP Options Processing
The NAT and NAPT functions handle and process the IP datagrams with options
set as described below. No command is available to set IP options.
The router does not process (and drops) any IP datagrams with the following IP
options:
Loose source and record route (type 131)
Strict source and record route (type 133)
Security (type 130)
Stream ID (type 136)
The router does process IP datagrams with the following IP options, but does not
provide its IP address or timestamp information in the response message:
Record route (type 7)
Timestamp (type 68)
Applications Supported by NAT
The router supports the following applications and protocols:
FTP
HTTP
Ping
RealPlayer
Telnet
TFTP