DNS Client Configuration Mode Commands


DNS Client Configuration Mode Commands
 
 
The DNS Client Configuration Mode is used to manage the system’s DNS interface and caching parameters.
 
Important: The commands or keywords/variables that are available are dependent on platform type, product version, and installed license(s).
 
bind address
Binds the DNS client to a pre-configured logical IP interface.
Product
SCM, SGSN
Privilege
Security Administrator, Administrator
Syntax
bind address ip_address [ port number ]
no bind address
no
Removes the binding of the client to a specified interface.
ip_address
Specifies the IP address of the interface to which the DNS client is being bound. ip_address must be expressed in IPv4 dotted decimal notation.
port number
Default: 6011
Specifies the UDP port number of the interface to which the DNS client is being bound. number must be an integer value from 1 to 65535.
Usage
Use this command to associated the client with a specific logical IP address.
Example
The following command binds the DNS client to a logical interface with an IP address of 1.2.3.4 and a port number of 6000:
bind address 1.2.3.4 port 6000
 
cache algorithm
Configures the method of use of the DNS VPN and session cache.
Product
SCM, SGSN
Privilege
Security Administrator, Administrator
Syntax
cache algorithm { central | local } { FIFO | LRU | LFU }
default cache algorithm { central | local }
default
Sets the DNS VPN and session cache method to default setting.
central | local
central: Specifies the central proclet (VPN manager)
local: Specifies the local proclet (session manager)
FIFO | LRU | LFU
FIFO: First in first out. This is the default setting for the central proclet.
LRU: Least recently used. This is the default value for the local proclet.
LFU: Least frequently used.
Usage
Use this command to configure the method by which entries are added and removed from the DNS cache.
Example
The following command configures the cache algorithm for the central proclet to least frequently used (LFU):
cache algorithm central lfu
 
cache size
Configures the maximum number of entries allowed in the DNS cache.
Product
SCM, SGSN
Privilege
Security Administrator, Administrator
Syntax
cache size { central | local } max_size
default cache size { central | local }
default
Sets the maximum number of entries allowed in the DNS cache to default setting.
{ central | local } max_size
central max_size: Specifies the maximum number of entries allowed in the central proclet cache. max_size must be an integer value from 100 to 65535 in length. The default value for the central proclet is 50000.
local max_size: Specifies the maximum number of entries allowed in the local proclet cache. max_size must be an integer value from 100 to 65535 in length. The default value for the local proclet is 1000.
Usage
Use this command to configure the maximum number of entries allowed in the DNS cache.
Example
The following command configures the cache size of the central proclet to 20000:
cache size central 20000
 
cache ttl
Configures the DNS cache time to live (TTL) for positive and negative responses.
Product
SCM, SGSN
Privilege
Security Administrator, Administrator
Syntax
cache ttl { negative | positive } seconds
default cache ttl { negative | positive }
no cache [ ttl { negative | positive } ]
no
Disables any or all configured DNS cache parameters.
default
Sets the DNS cache time to live for positive and negative responses to default setting.
{ negative | positive } seconds
negative seconds: Specifies the time to live for negative responses. seconds must be an integer value from 60 to 86400. The default value is 60 seconds.
positive seconds: Specifies the time to live for positive responses. seconds must be an integer value from 60 to 86400. The default value is 86400 seconds (1 day).
Usage
Use this command to adjust the DNS cache time to live.
Example
The following commands set the TTL DNS cache to 90 seconds for negative responses and 43200 seconds for positive responses:
cache ttl negative 90
cache ttl positive 43200
 
end
Exits the current mode and returns to the Exec Mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
end
Usage
Change the mode back to the Exec mode.
 
exit
Exits the current mode and returns to the previous mode.
Product
All
Privilege
Security Administrator, Administrator
Syntax
exit
Usage
Return to the previous mode.
 
resolver
Configure the number of DNS query retries and the retransmission interval once the response timer times out.
Product
SGSN
Privilege
Security Administrator, Administrator
Syntax
resolver { number-of-retries retries | retransmission-interval time }
default { number-of-retries | retransmission-interval }
default
Use this keyword to reset the specified resolver configuration to the default.
number-of-retries retries
Configures the number of DNS query retries on DNS response timeout.
retries: enter an integer from 0 to 4. Default is 2 retries.
retransmission-interval time
Configures the initial retransmission interval, in seconds, for retransmission after the DNS response timeout. The retransmission interval doubles after each retry when only one server is configured. In case both primary and secondary servers are configured, the retransmission time is doubled for the last retry.
time: enter an integer from 2 to 5. Default is 3 seconds.
Usage
Set the DNS retransmission retries or the retransmission interval. Issue the command twice to configure both parameters, one-at-a-time.
Example
The following command sets the DNS resolver retries to 4:
resolver number-of-retries 4
 
round-robin answer
This command configures the DNS client to return the DNS results in round-robin fashion if multiple results are available for a DNS query.
Product
SGSN
Privilege
Security Administrator, Administrator
Syntax
[ no | default ] round-robin-answers
no
Removes the configured round robin method for DNS answer.
default
Disabled the round robin method for DNS answer.
Usage
Use this command to configure the DNS client to return the DNS results in round-robin fashion if multiple results are available for a DNS query.
Example
The following command configures the DNS client to use round robin method for DNS query answers:
default ] round-robin-answers
 
 

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