Cabletron Systems SmartSwitch Router, User'S Reference Manual

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Chapter 14: Network Address Translation Configuration Guide
226 SmartSwitch Router User Reference Manual
NAT and FTP
File Transfer Protocol (FTP) packets require special handling with NAT, because the FTP
PORT command packets contain IP address information within the data portion of the
packet. It is therefore important for NAT to know which control port is used for FTP (the
default is port 21) and the timeout for the FTP session (the default is 30 minutes). If FTP
packets will arrive on a different port number, you need to specify that port to NAT.
To define FTP parameters to NAT, enter the following commands in Configure mode.
Monitoring NAT
To display NAT information, enter the following command in Enable mode.
Configuration Examples
This section shows examples of NAT configurations.
Static Configuration
The following example configures a static address binding for inside address 10.1.1.2 to
outside address 192.50.20.2:
Specify the FTP control port.
nat set ftp-control-port
<port number>
Specify the FTP session timeout.
nat set ftp-session-timeout
<minutes>
Display NAT information.
nat show [translations all|
<type>
]
[timeouts] [statistics]
et.2.2
(192.50.20.1/24)
et.2.1
(10.1.1.1/24)
Global Internet
IP network 10.1.1.0/24
Router
interface 10-net interface 192-net
10.1.1.2
Outbound: Translate source 10.1.1.2 to 192.50.20.2
Inbound: Translate destination 192.50.20.2 to 10.1.1.2