Shulou(Shulou.com)06/02 Report--

DNS: Domain Name Service, protocol (Cramp S, 53/udp, 53/tcp); application layer protocol

BIND:Bekerley Internat Name Domain, ISC (www.isc.org)

TCP: a connection-oriented protocol

UDP: User Datagram Protocol, connectionless protocol

Local name resolution profile: hosts

/ etc/hosts

% WINDOWS%/system32/drivers/etc/hosts

Top Level Domain: tld

Com, edu, mil, gov, net, org, int

Three categories: organizational domain, country domain (.cn, .iq, .HK, .tw), reverse domain

DNS query type:

Recursive query

Iterative query

Name server: the host in the domain responsible for resolving the names in this domain

Root server: 13 sets of servers

Resolution type:

Name-- > IP

IP-- > Name

Note: forward and backward parsing are two different namespaces and two different parsing trees.

Type of DNS server:

Primary DNS server

Secondary DNS server

Cache DNS server

Transponder

Master DNS server: maintain the domain parsing library server that is responsible for parsing; the parsing library is maintained by management.

Slave DNS server: copy (zone transfer) a parse library from the master DNS server or other from the DNS server

Serial number: the version number of the parsing library; premise: the content of the parsing library on the main server changes, and its sequence increases progressively.

Refresh interval: the interval between requests for synchronous parse libraries from the master server from the slave server

Retry interval: the interval between retries when a slave server fails to request a synchronous parsing library from the master server

Expiration time: when the master server can not be contacted from the slave server, how long will it take to give up from the server point of view and stop providing services

Notification mechanism:

Area transfer:

Full transfer: transfer the entire analysis library

Incremental transfer: transfer the part of the parse library that changes

DNS:

Domain:

Positive: FQDN-- > IP

Reverse: IP-- > FQDN

Each needs a parsing library to be responsible for the forward and reverse resolution of local domain names, respectively.

Positive region

Reverse region

FQDN: Full Qualified Domain Name fully qualified domain name

The process that a complete query request goes through:

Client-- > hosts file-- > DNS Service

Local Cache-- > DNS Server (recursion)-- > Server Cache-- > iteration (iteration)-- >

Analyze the answer:

The affirmative answer is:

Negative answer: the result cannot be returned for reasons such as the requested entry does not exist

Authoritative answer:

Non-authoritative answer:

Regional resolution library: consists of a number of RR:

Resource record: Resource Record, RR

Record type: a, AAAA, PTR, SOA, NS, CNAME, MX

SOA:Start Of Authority, the initial authorization record; a regional parse library has and can only have one SOA record, and must be the first record of the parse library

A:internet Address, function, FQDN-- > IP

AAAA: FQDN-- > IPv6

PTR: PoinTeR,IP-- > FQDN

NS: Name Server, dedicated to DNS servers that identify the current zone

CNAME:Canonical Name, alias record

MX: Mail eXchanger, mail exchanger

The format of the resource record definition:

Syntax: name [TTL] IN rr_type value

Note:

(1) TTL can inherit from global

(2) @ can be used to refer to the name of the current area

(3) multiple different values can be defined by multiple records for the same name; in this case, the DNS server will respond by polling.

(4) the same value may have multiple different definition names; it is defined by multiple different names pointing to the same value; this only means that the same host can be found through multiple different names.

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