1.0 Networking Fundamentals
1.6 Network Services
DHCP (Dynamic Host Configuration Protocol) - Automated IP configuration for network devices.
Scope - IP address range used and reserved IP addresses not to be used.
Exclusion Ranges - IP address range within the scope not to use.
Reservation - IP address reserved to provide as a static IP address.
Dynamic Assignment - Automatic IP address assigning.
Static Assignment - Non-changing IP address, typically to provide to a specific device.
Lease Time - The duration an IP address is assigned for.
Scope Options - Used to set additional network info when a host is assigned an IP address.
Available Leases - IP addresses available to be assigned.
DHCP Relay/IP Helper - Router that converts a device’s DHCP broadcast into a unicast to forward it to a DHCP server.
UDP Forwarding - Used when you are limited to the amount of destination you can communicate to, allows you to forward data to a UDP replicator which then can send to any number of destinations.
DNS (Domain Name System) - Protocol that translates IP addresses/domain names.
Record Types
Address (A vs AAAA) - Used to resolve a domain to IPv4 and IPv6 addresses respectively.
Canonical Name (CNAME) - Maps an alias name to the true domain name.
Mail Exchange (MX) - Indicates how email should be routed based on SMTP
Start of Authority (SOA) - Administrative DNS records for the DNS zone at the cutover point from the parent DNS zone.
Pointer (PTR) - Resolves an IP address to a domain. (reverse DNS lookup)
Text (TXT) - Originally made for human-readable DNS notes, can also be used to filter out spam email and to verify domain ownership.
Service (SRV) - Indicates a host and port for a given service. (VoIP, IM, etc)
Name Server (NS) - Indicates which DNS server is authoritative for a given domain.
Global Hierarchy - Domain Name Space hierarchy
Root DNS Servers - Top level domain in the Domain Name Space hierarchy.
Internal vs. External - IP addresses and Domains that reside within a network (internal) opposed to outside the network (external sites).
Zone Transfers - Process of copying the contents of the zone file on a primary DNS server to a secondary DNS server
Authoritative Name Servers - Contains data to provide in response to questions about domains in its zone.
Time To Live (TTL) - The amount of hops a packet will make before getting discarded.
DNS Caching - Temporarily stored data for previously looked up DNS data.
Reverse DNS/Reverse Lookup/Forward Lookup - Reverse translating a domain from an IP address.
Recursive Lookup - Source domain data from several other DNS servers.
Iterative Lookup - Source domain data directly from the DNS server involved.
NTP - Network Time Protocol, clock synchronization for network devices.
Stratum - Degrees away from “real time” (Atomic clock:0, highly accurate)
Clients - Connects to the network time server for syncing, stratum 2.
Servers - Network Time Server provides time data to network devices, stratum 1.