eG Help

You can configure the Citrix® NetScaler® appliance to function as an authoritative domain name server (ADNS server) for a domain. You can add the DNS resource records that belong to the domain for which the appliance is authoritative and configure resource record parameters. You can also configure the NetScaler appliance as a proxy DNS server that load balances a farm of DNS name servers that are either within your network or outside your network. You can configure the appliance as an end resolver and forwarder. You can configure DNS suffixes that enable name resolution when fully qualified domain names are not configured. The appliance also supports the DNS ANY query that retrieves all the records that belong to a domain.

Using the NS DNS test, you can monitor the DNS queries to the NetScaler appliance, and evaluate how efficiently the appliance handles these queries. DNS requests that were refused and invalid responses that were sent can thus be promptly detected, and their reasons investigated.

Measurement	Description	Measurement Unit	Interpretation
Dns_queries_received	Indicates the number of DNS queries received during the last measurement period.	Number
Auth_ans_queries	Indicates the number of queries that were authoritatively answered during the last measurement period.	Number	An ADNS (Authoritative DNS) server is a DNS server that contains complete information about a zone. To configure the NetScaler as an ADNS server for a zone, you must add an ADNS service, and then configure the zone. To do so, you add valid SOA (Start of Authority) and NS records for the domain. When a client sends a DNS request, the NetScaler appliance searches the configured resource records for the domain name. You can delegate a subdomain, by adding NS records for the subdomain to the zone of the parent domain. You can then make the NetScaler authoritative for the subdomain, by adding a "glue record" for each of the subdomain name servers. If GSLB is configured, the NetScaler makes a GSLB load balancing decision based on its configuration and replies with the IP address of the selected virtual server.
Mulit_query_req_recvd	Indicates the number of multi query requests received during the last measurement period.	Number
Server_query_sent	Indicates the number of server queries sent during the last measurement period.	Number
Dns_responses_received	Indicates the number of DNS responses received during the last measurement period.	Number
Cache_flushed	Indicates the number of times the cache was flushed during the last measurement period.	Number	The NetScaler can cache DNS responses (records) and can function as a DNS proxy. This enables the NetScaler to provide quick responses for repeated translations. To configure the NetScaler as a DNS proxy, you must enable caching of DNS records. You must also create a load balancing DNS virtual server, and DNS services, and then bind these services to the virtual server. The NetScaler provides two options, minimum time to live (TTL) and maximum TTL for configuring the lifetime of the cached data. The cached data times out as specified by your settings for these two options. The NetScaler checks the TTL of the DNS record coming from the server. If the TTL is less than the configured minimum TTL, it is replaced with the configured minimum TTL. If the TTL is greater than the configured maximum TTL, it is replaced with the configured maximum TTL. The NetScaler discards (flushes) a record stored in its cache when the time-to-live (TTL) value of the record reaches the configured value.
Server_res_recvd	Indicates the number of server responses received during the last measurement period.	Number
Cache_entries_flushed	Indicates the number of cache entries that were flushed during the last measurement period.	Secs
Updated_records	Indicates the number of A records that were updated during the last measurement period.	Number	You can add DNS records on the NetScaler, including address (A) records. Address (A) records are DNS records that map a domain name to an IPv4 address.
Non_exist_domain_query	Indicates the number of queries for which the records were not found in the domain during the last measurement period.	Number	If information pertaining to a requested domain does not exist, it indicates a negative response. This measure therefore reveals the count of negative responses.
Res_type_unsupported	Indicates the number of responses for which the requested response type was not supported during the last measurement period.	Number	Ideally, the value of this measure should be low.
Res_class_unsupported	Indicates the number of responses for which the response types were not supported during the last measurement period.	Number	Ideally, the value of this measure should be low.
Query_class_unsupported	Indicates the number of queries for which the base query class was not supported during the last measurement period.	Number
Invalid_query_format	Indicates the number of queries received with an invalid format during the last measurement period.	Number
Invalid_res_format	Indicates the number of responses received with a format error during the last measurement period.	Number	Ideally, the value of this measure should be 0.
Stray_answers	Indicates the number of stray answers received during the last measurement period.	Number	Ideally, the value of this measure should be 0.
Res_recvd_without_ans	Indicates the number of DNS responses received without an answer during the last measurement period.	Number	Responses received without an answer are deemed as negative responses. Ideally, the value of this measure should be 0.
Res_recvd_invalid_rd	Indicates the number of DNS responses received with an invalid resource data length during the last measurement period.	Number	Ideally, the value of this measure should be 0.
Mulit_query_disabled	Indicates the number of multi queries that were disabled during the last measurement period.	Number
Dns_request_refused	Indicates the number of DNS requests that were refused during the last measurement period.	Number	Ideally, the value of this measure should be 0.
Other_errors	Indicates the miscellaneous errors detected during the last measurement period.	Number	Ideally, the value of this measure should be 0.