Network Naming Flashcards
DNS Naming (max characters)
DNS naming convention allows for DNS names up to 255 characters, including the separating periods
Zone
A zone is a container for a single domain that gets filled with records.
Record
A record is a line in the zone data that maps a FQDN to an IP address
Authoritative Name Servers
DNS servers that hold the IP addresses and names of systems for a particular domain or domains in special storage areas called forward lookup zones. They also have reverse lookup zones.
Domain names must be registered with:
ICANN - Internet Corporation for Assigned Names and Numbers.
Domains must be redistered for internet use with ICANN
The most popular DNS server used in Linux is:
BIND
Foward Lookup Zone
The storage area in a DNS server to store the IP addresses and names of systems for a particular domain or domains.
Forward lookup enbles a system to determine an IP address by knowing the FQDN; Reverse lookup enables a system to determine anFQDN by knowing the IP address.
Reverse Lookup Zone
A DNS setting that resolves IP addresses to FQDNs. In other words, it does exactly the reverse of what DNS normally accomplishes using forward lookup zones.
Forward lookup enbles a system to determine an IP address by knowing the FQDN; Reverse lookup enables a system to determine anFQDN by knowing the IP address.
DNS Record Types:
SOA
Start of Authority - Defines the primary name server in sharge of the forward lookup zone. Each forward lookup zone requires a SOA
DNS Record Types:
NS
NS stands for ‘name server’ and this record indicates which DNS server is authoritative for that domain (which server contains the actual DNS records). A domain will often have multiple NS records which can indicate primary and backup name servers for that domain.
DNS Record Type:
CNAME
A Canonical Name or CNAME record is a type of DNSrecord that maps an alias name to a true or canonical domain name. CNAME records are typically used to map a subdomain such as www or mail to the domain hosting that subdomain’s content.
DNS Record Type:
MX
Mail Exchanger records are used exclusively by SMTP servers to determine where to send mail.
DNS Record Type:
SRV
Generic DNS record that suppoers any type of server.
_service._proto.name. TTL IN SRV priority weight port target.
- service - name of the service supported by this record
- proto - TCP or UDP
- name - the domain name for this server (ends with a period)
- TTL - time to lice in seconds
- priority - the priority of the target host; this is used when multiple servers are present (value is 0 when only one server)
- weight - an arbitrary value to give certian serices priority over others
- target - the FQDN of the machine providing the service, ending in a dot
_sip._tcp.testserve.com. 86400 IN SRV 0 5 5060 sipserver.mikemeyers.com.
DNS Record Type:
TXT
The ‘text’ record let’s a domain administrator enter text into the DNS record, as it was originally intended as a place for human-readable notes. However now it is also possible to put some machine-readable code into TXT records as well. One domain can have many TXT records and they are commonly used for Sender Policy Framework (SPF) codes that help an email server determine if a message is from a trusted source, as well as ownership verification of a domain. For example some webmaster tools will ask you to add a TXT record to your domain to prove you are that domain’s real owner.
Two Types of Forward Lookup Zones
Primary Zone - created on the DNS server that will act as the primary name server for that zone.
Secondary Zone - created on other DNS servers to act as backups to the primary zone.
