DNS: Domain name resolution:bind:berkeleyinternet Name Domain
L
DNS: Domain Name Service
domain name:www.baidu.com(hostname,fqdn:full qualified domain name, fully qualified)
DNS: name resolution:nameresolving name translation (behind the query process, database)
FQDN---------------------------IP
Www.baidu.com 180.97.33.107
Www.163.com 218.92.220.13
Nsswitch: providing a platform
/etc/nsswitch.conf
Hosts:files DNS
File:/etc/hosts
DNS:DNS
Stub resolver: name Resolver
Ping www.baidu.com ,stub resolve first find out if there is a record in/etc/hosts, if no more DNS parsing
Hosts
IPAddr FQDN ailases
218.92.220.13 www.163.com www
Iana:ip, FQDN,
Ftp:hosts
Icann:
TLD: organization domain . com,. org,. NET,. cc
country domain . cn,. TW,. HK,. IQ,
Reverse Domain Ip-> FQDN
Reverse: Ip->fqdn
Forward Direction: Fqdn->ip
DNS Server Type
Master DNS Server: Data modification
Auxiliary DNS Server: Request data synchronization
Serial The version number of the number data file;
Refresh Check time, how long to check
Retry Retry Time
Expire Expiration Time
Negative answer TTL negative answer cache duration
Cache DNS Server
Transponder
in the database, each entry is called a resource record ( Resource Record, RR)
Format of the resource record:
TTL 600;
NAME {TTL} in RRT VALUE
Www.mylinux.com. In A 1.1.1.1
1.1.1.1 in PTR www.mylinux.com
Resource record Type:
SOA (Start of authority): This record explains how zone transfers are implemented, andSOA must be the first record in this database.
Format:
ZONE NAME TTL in SOA FQDN (
Serial number
Refresh
Retry
Expire
Na ttl)
Time Unit: M ( minutes ),H ( hours ),D ( day ),W(week)
Mailbox Format: [Email protected]- written ->admin.mylinux.com
columns:
Mylinux.com. In SOA ns1.mylinux.com. Admin.mylinux.com. (
20160707; Serial Number
1H
5M
1W
1D)
NS (name server): ZONE Name->fqdn declares itself to be a DNS server
Mylinux.com. In NS ns.mylinux.com.
Ns.mylinux.com. In A 1.1.1.1
MX (Mail eXchanger): ZONE NAME->fqdn declares itself to be a mail server,
MX ( priority:0-99, the smaller the number, the higher)
Mylinux.com. In MX ten mail.mylinux.com.
Mail.mylinux.com. In A 1.1.1.1
A (address): FQDN--IPV4
Aaa:fqdn-IPv6
PTR (pointer): FQDN with IP
CNAME (Canonical NAME): FQDN->fqdn
Www2.mylinux.com. In CNAME www.mylinux.com.
Txt
CHAOS
SRV
Domain: Domain Logic Concepts
Area: Zone Physics Concept
. com
Mylinux.com. In NS ns.mylinux.com.
Ns.mylinux.com. In A 172.16.100.0/24
Mylinux.com. 172.16.100.0/24
www 172.16.100.10
Mail 172.16.100.11,mx
Create two zone files
Forward zone files:
Mylinux.com. In SOA ns.mylinux.com. Admin.mylinux.com. (
20160707
1H
5M
1W
1D)
Www.mylinux.com. In A 172.16.100.10
can be abbreviated as :
www in A 172.16.100.10
-------------------------------------------------------
Reverse zone file:
100.16.172.in-addr.arpa. In SOA ns.mylinux.com. Admin.mylinux.com. (
20160707
1H
5M
1W
1D)
10.100.16.172.in-addr.arpa. In PTR www.mylinux.com.
Shorthand:
Ten in PTR www.mylinux.com.
Zone Transfer Type:
Full zone transfer: AXFR
Incremental zone transfer: IXFR
Zone Type:
Primary zone: Master
From zone: Slave
Hint Area: hint
Forwarding Area: Forward
This article from "Linux operation and Maintenance" blog, declined reprint!
A detailed explanation of DNS service related concepts