3Com OfficeConnect 3C100XF Cli User's Manual - page 130
13-6
C
HAPTER
13: DNS C
OMMANDS
Set Commands
This section describes the following DNS Set commands:
set dns
set dns server preference
name
address
set dns
Sets the global parameters for DNS; both local DNS hosts (
list dns hosts
) and
remote DNS servers (
list dns servers
), and DNS caching and negative caching
parameters, in support of DNS host rotation for load balancing.
The following parameters are associated with this command:
cache
[enabled | disabled | clear]
cache_maxttl
domain_name
intercept_request
ncache
[enabled | disabled | clear]
ncache_maxttl
number_retries
timeout
These parameters are described in the following table.
Parameters
Description
cache
Enables or disables DNS caching. Setting to CLEAR flushes the DNS cache.
The default is
disabled
.
cache_maxttl
Maximum time in seconds DNS cache entries remain in the DNS cache
before they’re flushed. The range is
0 -
2147483
.
domain_name
Default domain designation to be used if no domain is specified (by
add
dns server
command) in the name to be resolved. For example: usr.com.
The limit is
64 ASCII
characters.
intercept_request
ncache
Enables or disables negative DNS caching. Setting to CLEAR flushes the
DNS negative cache. The negative DNS cache contains entries the DNS
server found to be in error. For example, if the host name abc.xyz.com
doesn’t exist, the DNS server will return a
non-existent name error.
ncache_maxttl
Maximum time in seconds DNS negative cache entries remain in the DNS
negative cache before they’re flushed. The range is
0 -
2147483
.
number_retries
Number of times the resolve name request will be sent to each Name
Server if the server fails to respond to a request before the timeout period.
The default is
1
.
The range is
1-5
.
timeout
Interval in seconds to wait before deciding a request to a Name Server has
timed out. Minimum interval and default is
5
seconds, maximum interval
is
245
seconds.