堅森-學習大小事

• DNS 最容易理解的說法是: 負責將好記的網域名稱翻譯成IP位址
• 一般而言, 如果想要上網到某個網頁, 通常會輸入名稱而不會輸入該網頁的IP位址
  • 假設要瀏覽台灣大學的網頁
    • 輸入: www.ntu.edu.tw  而不會輸入 140.112.8.116
  • 如何查找 www.ntu.edu.tw 的 IP address ?
    • 可以使用 nslookup 指令

• 完整網域名稱 (Full Qualified Domain Name, FQDN)
  • FQDN: [主機名稱] + [網域名稱] + [.]
• DNS Record Type
  • DNS SRV Record
    • 查詢指定服務的地址
    • DNS SRV 除了紀錄伺服器的地址, 還記錄了 Port
    • DNS SRV 還可以設定每個 Server address 的優先順序和權重
    • 根據優先順序及權重, 選取發出 DNS Query 的目標 Server address
      • 如圖: 可以設定 Priority: 1 Weight: 100  (Priority:小 →大; Weight: 大 → 小)

• DNS A Record Type
  • A 表示 IPv4 Address
  • AAAA 表示 IPv6 address
  • 用途為 IP address 查閱: 將網域名稱匹配到 IPv4 address
  • 範例:

 

• 常用的 DNS Server: bind9
  • 使用自定義的檔案
    • 先修改 named.conf.local

   - 重新啟動 bind9 server

     root@arcadyanubuntu:/etc/bind# /etc/init.d/bind9 restart
     root@arcadyanubuntu:/etc/bind# sudo systemctl restart bind9

 

root@arcadyanubuntu:/etc/bind# cat voip.arcadyan.com 
;
; BIND reverse data file for broadcast zone
;
$TTL	14400
@	   IN	SOA	voip.arcadyan.com. arcadyan.com. (
			      1		; Serial
			  3600		; Refresh
			  86400		; Retry
			2419200		; Expire
			 14400 )	; Negative Cache TTL
;
@	   IN	 NS	voip.arcadyan.com.
;voip       IN    A      192.168.88.11
;voip	   IN	 A	192.168.200.223
;voip 	   IN    A	192.168.214.168
;voip       IN    A      10.118.22.218
;voip       IN    A      5.6.5.6
;voip       IN    A      172.17.21.9
;voip       IN    A      192.168.88.112
;voip       IN    A      10.10.101.135
voip       IN    A       172.16.1.1
;voip       IN    A      7.8.9.10
;test       IN    A       172.16.1.188
test	    IN	  A      2.4.6.8 
;voip1      IN    A      172.16.232.1
;eit        IN    A      172.16.132.1
;test       IN    A      172.16.111.1
;test1      IN    A       3.5.7.9
;voip       IN    AAAA   2001:470:23:ed9::2
;voip       IN     AAAA   3001:200:0:10::23

;_sips._tcp.voip.arcadyan.com. IN    SRV    1 50   5061 voip.arcadyan.com.
;_sips._tcp.ys.dnssrv.test.    IN    SRV    1 0   5061 voip.arcadyan.com.
;_sips._tcp.voip.arcadyan.com. IN    SRV    1 100  5061 test.arcadyan.com.
;_sip._udp.voip.arcadyan.com.  IN    SRV    2 0   5060 voip.arcadyan.com.
;_sip._udp.voip.arcadyan.com.  IN    SRV    1 50  5060 test.arcadyan.com.
;_sip._tcp.voip.arcadyan.com.  IN    SRV    1 0   5060 voip.arcadyan.com.
;DNS_SRV_Testing
_sip._udp.voip.arcadyan.com.  IN    SRV    2 100   5060 voip.arcadyan.com.
;_sip._udp.one.arcadyan.com.  IN    SRV    2  50   5060 voip.arcadyan.com.
_sip._udp.voip.arcadyan.com.  IN    SRV    1  50   5060 test.arcadyan.com.
;_sip._udp.voip.arcadyan.com.  IN    SRV    1 100   5068 test1.arcadyan.com.
;_sip._udp.voip.arcadyan.com.  IN    SRV    4 0    5060 voip.arcadyan.com.

;_sip._udp.voip1.arcadyan.com. IN    SRV    1 0    5065 voip1.arcadyan.com.
;_sip._udp.voip.arcadyan.com. IN    SRV    1 0    5065 voip1.arcadyan.com.
;_sip._udp.voip.arcadyan.com.   IN    SRV    1 50   5066 voip.arcadyan.com.

naptr.arcadyan.com. NAPTR 10 100 "S" "SIP+D2T" "" _sip._tcp.voip.arcadyan.com.
naptr.arcadyan.com. NAPTR 20 200 "S" "SIP+D2U" "" _sip._udp.voip.arcadyan.com.
naptr.arcadyan.com. NAPTR 30 300 "S" "SIPS+D2T" "" _sips._tcp.voip.arcadyan.com.

root@arcadyanubuntu:/etc/bind# cat named.conf.local
//
// Do any local configuration here
//

// Consider adding the 1918 zones here, if they are not used in your
// organization
//include "/etc/bind/zones.rfc1918";
zone "arcadyan.com" {
    type master;
    file "/etc/bind/voip.arcadyan.com";
};
root@arcadyanubuntu:/etc/bind#