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tech_notes:dns [2024-05-18 Sat wk20 17:13] – baumkptech_notes:dns [2024-06-16 Sun wk24 10:20] (current) – [DNS Performance Checker] baumkp
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-There are a number of levels of DNS. +There are a number of levels of DNS, the system interrogates in the following order: 
-  - host file,  this is a basic file on each computer where +  - host file,  this is a basic file on each computer operating system 
 +    -The usual automatic entries are: 
 +      -The local machine host name and ip address 
 +      -The loop back address 
 +  - Additional manual entries can be added for any host name and IP address.  (This can be hand on occassions, such as setting up VPNs where the setup process changes internet access for DNS stop working.  The host file manual can still allow address resolution.
   - local dns resolver   - local dns resolver
     - machine based     - machine based
 +      - many operating systems have a local caching DNS server installed to improve DNS performance.
     - LAN based     - LAN based
-  - ISP resolver+      - This can act as a local caching DNS server and also be used for LAN  
 +  - public resolver
   - authoritative domain resolver   - authoritative domain resolver
  
 +=====Public DNS providers=====
 +  - [[https://www.quad9.net/|Quad9]], free no commercial foundation
 +    - IPv4 (filtered)
 +      -  9.9.9.9
 +      - 149.112.112.112
 +    - IPv6 (filtered)
 +      - 2620:fe::fe
 +      - 2620:fe::9
 +    - [[https://www.quad9.net/service/service-addresses-and-features|Quad9 Service Addresses & Features]] some other options
 +  -  [[https://www.opendns.com/|OpenDNS]], belongs to Cisco
 +    - IPv4
 +      - 208.67.222.222
 +      - 208.67.220.220
 +    - IPv4 (filtered family shield, not-configurable)
 +      - 208.67.222.123
 +      - 208.67.220.123
 +    - IPv6 (filtered) 
 +      - 2620:119:35::35
 +      - 2620:119:53::53
 +    - IPv6 (unfiltered)
 +      - 2620:0:ccc::2
 +      - 2620:0:ccd::2
 +  - [[https://one.one.one.one/dns/|one.one.one.one]] (Cloudflare)
 +    - IPv4 (unfiltered)
 +      - 1.1.1.1
 +      - 1.0.0.1
 +    - IPv6 (unfiltered) 
 +      - 2620:4700:4700::1111
 +      - 2620:4700:4700::1001
 +    -  See [[https://one.one.one.one/family/|one.one.one.one/family]] for filtered options
 +
 +=====Linux DNS Setup=====
 +The local OS DNS servers are specified in ''/etc/resolv.conf''
 +
 +The bind9 file that configs the DNS forwarders is ''/etc/bind/name.conf.options'', the DNS ''forwarders'' are configured.
 +
 +The kea dhcp configuration has the following related to DNS and gateway setup.
 +++++dhcpv4.conf|
 +<code yaml>  "subnet4": [
 +    {
 +      "subnet": "192.168.1.0/24",
 +
 +      // There are no relays in this network, so we need to tell Kea that this subnet
 +      // is reachable directly via the specified interface.
 +      "interface": "enp1s0",
 + 
 +     "pools": [
 +        {
 +          "pool": "192.168.1.100 - 192.168.1.200"
 +        }
 +      ],
 +    "option-data": [
 +      {
 +        "name": "routers",
 +        "data": "192.168.1.1"
 +      },
 +      {
 +        "name": "domain-name-servers",
 +        "data": "192.168.1.14,192.168.1.2,9.9.9.9"
 +      }
 +    ],</code>
 +++++
 +
 +=====DNS Performance Checker=====
 +A good resource for checking DNS performance is from [[https://www.grc.com|GRC Gibson reserch Corporation (Steve Gibson)]].  The speed checker bench marking program [[https://www.grc.com/dns/benchmark.htm|GRC DNS Bench marker]] is only Windows based.  It reportedly runs in Linux/WINE.
  
  
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