GeoDNS

說明

如果要做到類似 Cloudflare 分散式的 CDN 分流服務，除了需要 Reverse Proxy 服務以外，還要再搭配 GeoDNS 服務，這樣用戶在存取網站時，就能依照自己所屬的國家，使用連線最近的 Reverse Proxy，進而達到網站分流與加速網站存取速度。

本篇運用 Docker 技術就能在幾分鐘內完成佈署 GeoDNS 所有需要的元件，這樣就可以將時間用在設定網域上。

開始佈署

新增服務目錄

mkdir docker-geodns
cd docker-geodns/ 

新增 docker-compose.yml

version: '2'

services:
  geodns:
    restart: always
    image: sameersbn/bind:9.10.3-20180127
    container_name: geodns
    ports:
     - "53:53/udp"
     - "53:53/tcp"
    environment:
     - ROOT_PASSWORD=yourpassword
     - WEBMIN_ENABLED=false
    volumes:
     - /docker_vol/geodns/data:/data

NOTE:

- 記得變更 root  密碼

- 如果需要 Webmin 管理套件，可設定為 true

- 若想了解這個實作使用的 docker image 更多資訊，可參閱：https://hub.docker.com/r/sameersbn/bind/

新增設定檔需要的目錄

mkdir  /docker_vol/geodns/data

新增並啟動服務 geodns

docker-compose up -d

完成

設定 DNS

下載檔案 GeoIP.acl http://geoip.site/download/MaxMind/GeoIP.acl.gz

wget http://geoip.site/download/MaxMind/GeoIP.acl.gz
gunzip GeoIP.acl.gz
cp GeoIP.acl /docker_vol/geodns/data/bind/etc 

編輯 /docker_vol/geodns/data/bind/etc/named.conf

...
 include "/etc/bind/named.conf.options";
include "/etc/bind/named.conf.local";
//include "/etc/bind/named.conf.default-zones";
...

註解第三行，並加上以下幾行

// GeoDNS Configuration
// The download link to the GeoIP.acl
// http://geoip.site/download/MaxMind/GeoIP.acl.gz
//
// acl file sepified the IP zones of countries.
include "/etc/bind/GeoIP.acl";  

// view settings for all countries
view "USA" {
  // The contents of this view will be presented to users
  // from the USA.
  match-clients { US; };
  zone "example.com" {
    // This is my zonefile with the US view.
    file "/etc/bind/zones/usa/example.com.db";
    type master;
  };
};

view "Taiwan" {
  // The contents of this view will be presented to users
  // from the Taiwan.  
  match-clients { TW; };
  zone "example.com" {
    file "/etc/bind/zones/taiwan/example.com.db";
    type master;
  };
};

view "Global" {
  // The contents of this view will be presented to users
  // outside the USA and Taiwan.
  zone "example.com" {
    // This is my zonefile with the default view.
    file "/etc/bind/zones/global/example.com.db";
    type master;
  };
}

TIPs：

view 名稱可自訂

match-clients 必須符合 GeoIP.acl，可設定多個

新增不同國家的網域設定檔

/docker_vol/geodns/data/bind/etc/zones/usa/example.com.db

 ; Content for USA views
$TTL 3600
example.com. IN     SOA    ns1.example.com. webmaster.mail.example.com. (
                            2017050403  ; Serial
                            3H          ; refresh after 3 hours
                            1H          ; retry after 1 hour
                            1W          ; expire after 1 week
                            1D)         ; minimum TTL of 1 day
                IN      NS      ns1.example.com.
                IN      NS      ns2.example.com.
; Content for US view
                IN      TXT     "US view"
; IP from USA
                IN      A       1.1.1.3
; First nameserver IP in USA
ns1             IN      A       198.51.100.24
; Second nameserver IP in USA
ns2             IN      A       198.51.100.42
; GLUE Nameservers that do the Geo localization.
a               IN      A       1.1.1.1
b               IN      A       1.1.1.2

/docker_vol/geodns/data/bind/etc/zones/taiwan/example.com.db

 ; Content for Taiwan views
$TTL 3600
example.com. IN     SOA    ns1.example.com. webmaster.mail.example.com. (
                            2017050403  ; Serial
                            3H          ; refresh after 3 hours
                            1H          ; retry after 1 hour
                            1W          ; expire after 1 week
                            1D)         ; minimum TTL of 1 day
                IN      NS      ns1.example.com.
                IN      NS      ns2.example.com.
                IN      TXT     "Taiwan view"
                IN      A       2.2.2.3
; First nameserver IP 
ns1             IN      A       198.51.100.24
; Second nameserver IP 
ns2             IN      A       198.51.100.42
; Nameservers that do the Geo localization.
a               IN      A       2.2.2.1
b               IN      A       2.2.2.2

/docker_vol/geodns/data/bind/etc/zones/global/example.com.db

; Content for Global views
$TTL 3600
example.com. IN     SOA    ns1.example.com. webmaster.mail.example.com. (
                            2017050403  ; Serial
                            3H          ; refresh after 3 hours
                            1H          ; retry after 1 hour
                            1W          ; expire after 1 week
                            1D)         ; minimum TTL of 1 day
                IN      NS      ns1.example.com.
                IN      NS      ns2.example.com.
                IN      TXT     "Global view"
                IN      A       9.9.9.3
; First nameserver IP 
ns1             IN      A       203.0.113.24
; Second nameserver IP 
ns2             IN      A       203.0.113.42
; Nameservers that do the Geo localization.
a               IN      A       9.9.9.1
b               IN      A       9.9.9.2

重啟服務

docker-compose stop
docker-compose start 

測試 DNS

透過 VPN 或使用雲端主機方式切換成不同國家的連線。測試 DNS 指令可用

host a.example.com xxx.xxx.xxx.xxx

- 將 xxx.xxx.xxx.xxx 改成 GeoDNS 主機 IP

若在美國，網域會解析成 IP 1.1.1.1
若在台灣，網域會解析成 IP 2.2.2.1
其他國家，網域會解析成 IP 9.9.9.1