Explaining Network Services Flashcards
1
Q
DCHP
A
Dynamic Host Configuration Protocol
- Automatic allocation of an IP adress, subnet mask and additional parameters, like default gateway or DNS server
- Host is configured to user DHCP by specifying in TCP/IP configuration that it shoud automatically obtain IP
2
Q
DHCP Server
A
- Normally deployed as service of network opreating system or through appliance such as a switch or router
- Must be allocated a static IP address and configured with a pool of IPs and a subnet masks
3
Q
Scope
A
- Range of addresses and options configured to a single subnet
- Must provide start and end IP address and subnet mask
- No scope can cover more than one subnet or vice versa
4
Q
DHCP Lease Time
A
- Client can renew lease when at least half of the time has elapses (T1 Timer).
- If DHCP server does not respond, client attempts to rebind same lease configuration with any DHCP server, by default at 87.5% of lease time up (T2 timer)
- Long lease time mean less need to renew
- Short least time means IP pool is refilled more ofte.
5
Q
DHCP Options
A
- Other IP related settings offers in DHCP configuraitons
- Each is identified with tag byte or decimal value between 0-255
- ExampleSS:
Default gateway
IP address of DNS server
DNS suffixx
Useful server options like NTP, TFTP or VoIP proxy
6
Q
DCHP Reservations
A
- Mapping of MAC address to specific IP address withing DHCP server address pool
- When server receives request from given interface, it always gives same IP address
- Automatically allocated reserveration refers to address that is permanently leased to a client
- Distinct from Static allocation as the administrator does not determine which specific IP address will be leased
7
Q
DHCP Relay
A
- Configuration to provide forwarding of DHCP traffic between subnets
- Routers that can do it are RFC 1542 Compliant
- Intercepts DHCP broadcast frames and applies appropriate unicast address for DHCP server
- Reduces the need for multiple DCHP servers for each subnet
8
Q
IP Helper
A
- Configuration on router to allow set types of brodcast traffic to be forwarded to an interface.
- Supports function of DHCP Relay
9
Q
SLAAC
A
Stateless Address Autoconfiguration
- IPv6 process that locates routers and generates host address with suitable network prefixx automatically.
- DCHPv6 is often just used for option settings rather than leases for host addresses.
10
Q
Host name
A
- Assigned to computer by administrator
- Must be unique on local network
11
Q
FQDN
A
Fully qualified domain name
- Used to provide unique indentity for a host belonging to particular network
- Made up of host name and domain suffix
- Domain name must be registered with registrar to ensure it is unique
- Must follow certain rules:
1. host name must be unique within domain
2. Total length cannot exceed 253 characters, with each label(part of name defined by a period) not exceeding 63
3. Use letter, digit and hyphen characters only.
4. not case sensitive
12
Q
Iterative Lookups
A
- Name server responds to query with either requested record or address of name server at a lower level that is authoritative for the namespace
- Makes no effort to make queries for information it does not have.
13
Q
DNS
A
Domain Name System
- Global hierarchy of distributed names server databases that contain information on domains and hosts withing domains.
- At top is the root, which just contains .
- Next is top level domains(.com,.org,.uk., .gov, etc.)
-
14
Q
Recursive lookup
A
- if queried server is not authoritative, it does take on take of querying other name servers until it finds requested record or times out.
- Name servers listed in clients TCP/IP configuration accept recursive queries
15
Q
Resource Records
A
- Record in DNS zone that allows a name server to resolve queries for names and services hosted into IP addresses.
- Can be updated manually (statistically) or can be generated dynamically
