Zhone 2004 用户指南
A p p l i c a t i o n N o t e s
C-3
Configuring NAT UDP Timeout
When a non-TCP connection is made through NAT, a context block is
allocated from the IAD’s memory. This context block is freed when the
timeout period has been exceeded with no data. In most applications, the
default value of 2 min (120 s) will be sufficient. If the application features a
large number of very short UDP, AH, or ESP connections, this value may
need to be lowered. If the application features connections with longer idle
times, this value may need to be increased.
allocated from the IAD’s memory. This context block is freed when the
timeout period has been exceeded with no data. In most applications, the
default value of 2 min (120 s) will be sufficient. If the application features a
large number of very short UDP, AH, or ESP connections, this value may
need to be lowered. If the application features connections with longer idle
times, this value may need to be increased.
Accessing LAN Devices from the Internet
If you want to access a LAN device from the Internet (i.e., Web server, FTP
server, etc.), the device must be configured in NAT to allow access from the
Internet. There are two ways to do this: through a NAT Local Server entry or
through a NAT Alias entry.
server, etc.), the device must be configured in NAT to allow access from the
Internet. There are two ways to do this: through a NAT Local Server entry or
through a NAT Alias entry.
NAT Local Server Configuration
A NAT Local Server entry is used when the local device shares its IP address
with the WAN port of the IAD. Only the configured protocol and port will be
visible from the Internet. When the Local Server is configured, the following
information must be entered:
with the WAN port of the IAD. Only the configured protocol and port will be
visible from the Internet. When the Local Server is configured, the following
information must be entered:
•
Translated IP address
− local IP address, as seen from the LAN.
•
Protocol
− TCP, UDP, AH, ESP, or both UDP and TCP.
•
Translated Port Number
− port number on which the local server sees the
service (UDP and TCP only).
•
Standard Port Number
− port number on which the Internet sees the service
(UDP and TCP only).
For current port number assignments, please see http://www.iana.org/
assignments/port-numbers.
assignments/port-numbers.
Note that TCP port 1723 is used to select Point-to-Point Tunneling Protocol
(PPTP) and TCP port 1720 is used to select ViaVideo. When using ViaVideo
units through NAT, the following limitations apply.
(PPTP) and TCP port 1720 is used to select ViaVideo. When using ViaVideo
units through NAT, the following limitations apply.
•
Only one Via Video inside of NAT may accept calls.
•
All ViaVideo units in the network must be configured to use fixed ports 3230
− 3235.
•
All ViaVideo units inside of NAT must be configured to use NAT and must
have the IAD’s WAN address configured.
have the IAD’s WAN address configured.
If Internet access of a local Telnet server at TCP port 23 is desired, it will be
necessary to reconfigure the Telnet server port of the IAD. Refer to
“Configure Port IP Address” on page 4-16 for further information.
necessary to reconfigure the Telnet server port of the IAD. Refer to
“Configure Port IP Address” on page 4-16 for further information.
NAT Alias Configuration
A NAT Alias entry is used when the local device is assigned a unique IP
address from the WAN port of the IAD. The local device will be totally
address from the WAN port of the IAD. The local device will be totally