[macOS] DNSのキャッシュクリアと、DNSサーバ指定で問合せする方法

下記のコマンドで、macOSにてDNSのキャッシュクリアや、DNSサーバを指定してIPv4のDNSクエリを行う事ができます

コマンド

DNSの問い合わせを行う(IPv4)

dig -4 my-domain.example.com

DNSサーバーを指定してDNS問い合わせを行う(IPv4)

dig -4 @ns-xxx.awsdns-xx.com my-domain.example.com

DNSキャッシュをクリアする(macOS 10.10.4以降の場合)

sudo killall -HUP mDNSResponder

マニュアル

digと、mDNSResponderのマニュアル抜粋です

NAME
       dig - DNS lookup utility

SYNOPSIS
       dig [@server] [-b address] [-c class] [-f filename] [-k filename] [-m] [-p port#]
           [-q name] [-t type] [-v] [-x addr] [-y [hmac:]name:key] [-4] [-6] [name] [type]
           [class] [queryopt...]

       dig [-h]

       dig [global-queryopt...] [query...]

SIMPLE USAGE
       A typical invocation of dig looks like:

            dig @server name type

       where:

       server
           is the name or IP address of the name server to query. This can be an IPv4 address
           in dotted-decimal notation or an IPv6 address in colon-delimited notation. When the
           supplied server argument is a hostname, dig resolves that name before querying that
           name server.

           If no server argument is provided, dig consults /etc/resolv.conf; if an address is
           found there, it queries the name server at that address. If either of the -4 or -6
           options are in use, then only addresses for the corresponding transport will be
           tried. If no usable addresses are found, dig will send the query to the local host.
           The reply from the name server that responds is displayed.

       name
           is the name of the resource record that is to be looked up.

       type
           indicates what type of query is required -- ANY, A, MX, SIG, etc.  type can be any
           valid query type. If no type argument is supplied, dig will perform a lookup for an
           A record.

OPTIONS
       -4
           Use IPv4 only.

NAME
mDNSResponder -- Multicast and Unicast DNS daemon

SYNOPSIS
mDNSResponder

DESCRIPTION
mDNSResponder（システムによってはmdnsdとも呼ばれます）は、マルチキャストDNSおよびDNSサービスディスカバリーを実装するために起動時に呼び出されるデーモンです。
Mac OS X 10.6 (Snow Leopard) の場合、mDNSResponderはシステム全体のユニキャストDNSリゾルバでもあります。
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