Nat Configuration Task List - 3Com MSR 50 Series Configuration Manual

NAT Configuration
Task List
streaming protocol (RTSP), H.323, Netmeeting 3.01, and NetBIOS over TCP/IP
(NBT).
n
The support for the special protocols varies by device models.
NAT multiple-instance
This feature allows users from different MPLS VPNs to access external networks
through the same outbound interface. It also allows them to have the same
internal network address. The process works as follows:
When an MPLS VPN user communicates with an external network, NAT replaces
its internal IP address and port number with the NAT gateway's external IP address
and port number. It also records the relevant MPLS VPN information, such as the
protocol type and router distinguisher (RD for short). When the response packet
arrives, the NAT gateway then restores the external IP address and port number to
the internal IP address and port number. Additionally, the NAT gateway can
identify the users who access the external network. Besides NAT, NAPT also
supports multiple-instance.
The multiple-instance feature can also apply to internal servers so that external
users can access an internal host of an MPLS VPN. For example, in MPLS VPN1, the
host that provides WWW service has an internal address 10.110.1.1. The host can
use 202.110.10.20 as an external IP address so that the Internet users can access
the WWW service in MPLS VPN1 through this external address.
Follow the following steps to configure NAT:
To do...
Enter system view
Define an address
pool
Configure address
translation
Configure an internal
server
Configure NAT aging
time
Use the command...
system-view
nat address-group
group-number start-address
end-address
Refer to "Configuring
Address Translation" on
page 1816
Refer to "Configuring
Internal Server" on page
1818
nat aging-time { default |
{ dns | ftp-ctrl | ftp-data |
icmp | pptp | tcp | tcp-fin |
tcp-syn | udp } seconds }

NAT Configuration Task List

Remarks
-
Optional
Not necessary when the router has been
configured with Easy IP.
Required
Optional
Optional
By default, NAT aging time varies by
protocols:
60 seconds for DNS;
7,200 seconds for FTP ctrl;
300 seconds for FTP data;
60 seconds for ICMP;
86,400 seconds for PPTP;
86,400 seconds for TCP;
60 seconds for TCP fin, TCP rst,
3600 seconds for TCP syn;
300 seconds for UDP.
1815