package envoy.extensions.network.dns_resolver.cares.v3

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Configuration for c-ares DNS resolver. [#next-free-field: 9]

• repeated config.core.v3.Address resolvers = 1

  A list of dns resolver addresses. :ref:`use_resolvers_as_fallback<envoy_v3_api_field_extensions.network.dns_resolver.cares.v3.CaresDnsResolverConfig.use_resolvers_as_fallback>` below dictates if the DNS client should override system defaults or only use the provided resolvers if the system defaults are not available, i.e., as a fallback.

• bool use_resolvers_as_fallback = 3

  If true use the resolvers listed in the :ref:`resolvers<envoy_v3_api_field_extensions.network.dns_resolver.cares.v3.CaresDnsResolverConfig.resolvers>` field only if c-ares is unable to obtain a nameserver from the system (e.g., /etc/resolv.conf). Otherwise, the resolvers listed in the resolvers list will override the default system resolvers. Defaults to false.

• bool filter_unroutable_families = 4

  The resolver will query available network interfaces and determine if there are no available interfaces for a given IP family. It will then filter these addresses from the results it presents. e.g., if there are no available IPv4 network interfaces, the resolver will not provide IPv4 addresses.

• optional config.core.v3.DnsResolverOptions dns_resolver_options = 2

  Configuration of DNS resolver option flags which control the behavior of the DNS resolver.

• optional google.protobuf.UInt32Value udp_max_queries = 5

  This option allows for number of UDP based DNS queries to be capped. Note, this is only applicable to c-ares DNS resolver currently.

• optional google.protobuf.UInt64Value query_timeout_seconds = 6

  The number of seconds each name server is given to respond to a query on the first try of any given server. Note: While the c-ares library defaults to 2 seconds, Envoy's default (if this field is unset) is 5 seconds. This adjustment was made to maintain the previous behavior after users reported an increase in DNS resolution times.

• optional google.protobuf.UInt32Value query_tries = 7

  The maximum number of query attempts the resolver will make before giving up. Each attempt may use a different name server. Note: While the c-ares library defaults to 3 attempts, Envoy's default (if this field is unset) is 4 attempts. This adjustment was made to maintain the previous behavior after users reported an increase in DNS resolution times.

• bool rotate_nameservers = 8

  Enable round-robin selection of name servers for DNS resolution. When enabled, the resolver will cycle through the list of name servers for each resolution request. This can help distribute the query load across multiple name servers. If disabled (default), the resolver will try name servers in the order they are configured. Note: This setting overrides any system configuration for name server rotation.