Difference between revisions of "BIND&DNS Notes"
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| − | [[Category: OPS335]][[Category: | + | [[Category: OPS335]][[Category:rchan]] |
= What is DNS (Domain Name System)? = | = What is DNS (Domain Name System)? = | ||
* a hierarchical, distributed database | * a hierarchical, distributed database | ||
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* Domains and Domain Names | * Domains and Domain Names | ||
* Zones | * Zones | ||
| + | * [http://www.zytrax.com/books/dns/ch2/index.html#recursive Recursive and iterative queries] (with diagram) | ||
| + | |||
= DNS Servers = | = DNS Servers = | ||
== Authoritative Name Servers == | == Authoritative Name Servers == | ||
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A name server which performs recursive lookups for local clients. Recursive name servers normally cache the results of the lookups they perform to improve performance. | A name server which performs recursive lookups for local clients. Recursive name servers normally cache the results of the lookups they perform to improve performance. | ||
* Forwarder | * Forwarder | ||
| − | + | Sometimes a caching name server may not perform the recursive lookup all by itself. It can forward some or all of the queries to another caching name server, commonly referred to as a forwarder. | |
= BIND Configuration File = | = BIND Configuration File = | ||
Latest revision as of 09:56, 8 October 2015
Contents
What is DNS (Domain Name System)?
- a hierarchical, distributed database
- for mapping Internet host names to IP addresses and vice versa
- provides mail routing information
What are the components in the DNS?
- DNS Clients
- resolver library
- DNS server
DNS clients (e.g. Web browser is one of those) look up information in the DNS by calling a resolver library, which sends queries to one or more name servers and interprets the response.
- Domains and Domain Names
- Zones
- Recursive and iterative queries (with diagram)
DNS Servers
Authoritative Name Servers
A name server which contains the complete data for a zone.
- The primary master DNS server: maintains the master copy of the zone data
- Slave DNS servers: (aka secondary servers) load the zone contents from another server using a replication process known as zone transfer.
Non-authoritative Name Servers
- Caching Name Server, or recursive name server
A name server which performs recursive lookups for local clients. Recursive name servers normally cache the results of the lookups they perform to improve performance.
- Forwarder
Sometimes a caching name server may not perform the recursive lookup all by itself. It can forward some or all of the queries to another caching name server, commonly referred to as a forwarder.
BIND Configuration File
Caching ONLY name server
Minimal Configuration
acl intnet { 192.168.99.0/24; 172.16.0.0/16; };
options {
directory "/var/named";
allow-query { intnet; };
};
zone "." {
type hint;
file "named.cache";
};
Authoritative Primary Name Server
Minimal Configuration
options {
directory "/var/named";
allow-query { any; };
recursion no;
};
zone "ops335.com" {
type master;
file "ops335.com.db";
notify yes;
allow-transfer {
192.168.99.54;
};
};
Authoritative Secondary Name Server
Minimal Configuration
options {
directory "/var/named";
allow-query { any; };
recursion no;
};
zone "ops335.com" {
type slave;
file "ops335.com.bk";
masters { 192.168.99.53; };
};
Mix-mode Name Server
Minimal Configuration
acl intnet { 192.168.99.0/24; 172.16.0.0/16; };
options {
directory "/var/named";
allow-query { intnet; };
};
zone "." {
type hint;
file "named.cache";
};
zone "ops335.com" {
type slave;
file "ops335.com.bk";
masters { 192.168.99.53; };
Root Zone and Root Name Server
Root Name Servers
- named.cache or
- named.root
Root Zone
- root.zone and
- root.zone.gz (gzip of root.zone)
