BelAir20E User Guide
BelAir20E Auto-configuration
April 2, 2012
Confidential
Document Number BDTM02201-A01 Standard
The
dns-server
parameter controls DNS server IP addresses. Up to two DNS
servers are supported. See
“Configuring the Domain Name System Lookup
.
The
tftp-download
parameter controls two DHCP options: TFTP server IP
address and script file. Enabling this option causes a TFTP session to be created
and the script file to be downloaded and executed during startup.
The
time-server
parameter controls the IP address for a time server. Two time
servers are supported. This information is used by the SNTP service. See
“Managing an SNTP Server” on page 52
.
The
time-offset
parameter controls the time offset value that is used by the
SNTP service. See
“Managing an SNTP Server” on page 52
.
The TFTP server IP address and the script file are downloaded and executed
only during a startup. If the script on the server changes, it is not sent to the
node until the next time the node reboots or starts up.
If DNS and SNTP data on the DHCP server changes, then it is sent to the node
whenever the node renews DHCP information. The new DNS and SNTP data
then takes effect immediately.
In all cases, DNS and SNTP data provided by the DHCP server overrides any
data configured locally.
DNS
With this method, the BelAir20E uses DNS to connect to an FTP server
containing a script file to be executed during startup.
When the BelAir20E starts up with factory default settings, it looks for a DHCP
server to assign its IP address.
If the DHCP server provides a TFTP server IP address and script file name,
then the BelAir20E performs auto-configuration based on these values. See
.
If DHCP server does not provide a TFTP server IP address and script file name,
then the BelAir20E obtains the script file based on DNS information from the
DHCP server as follows:
1 The BelAir20E uses DHCP to obtain the DNS server IP address and domain
name from the DHCP server.
2 The BelAir20E attempts to open a session to an FTP host called
bnconfigserv
using local DNS settings. The host name
bnconfigserv
is
hard-coded in the BelAir20E and cannot be changed. If unsuccessful, it opens