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Computer Networks
Term | Definition |
---|---|
A record | Refers to IPv4 address of host |
AAAA Re | refers to host's IPv6 address |
All-nodes multicast | = FF02::2 |
All-routers multicast | = FF02::2 |
Anycast address | Used to deliver an IP packet to only one network interface belonging to the corresponding anycast group |
ARPA | Address and Routing Parameter Area domain |
Assigned multicast address | Reserved for a group of devices using the same protocol or service (e.g. DHCPv6) |
Benefits of using a VLAN | More secure networks Better preforming networks Cost-saving networks More manageable networks |
C | Directly connected network |
ccTLDs | Country Code Top-level domains |
CGN | Carrier Grade NAT |
CNAME record | Canonical Name Record |
D | Dynamic routes which were automatically added to routing table y using routing protocol (EIGRP) |
DAD | Duplicate Address Detection |
Data VLAN | Transports data generated by users |
Default gateway | Router connected to same local network segment |
Default route ('gateway of last resort') | Route that's followed by default if no specific route to a network is found |
Default route in routing table | Route the packets must follow if destination address doesn't match any other network address in routing table |
Default VLAN | After starting a new switch, all ports are part of the same VLAN = default VLAN |
DHCP | Dynamic Host Configuration Protocol |
DHCP ACK | DHCP Acknowledgement |
DHCP Discover | Clients requests an IP address via IP broadcasting |
DHCP NACK | DHCP Not Acknowledgement |
DHCP Offer | All DHCP servers propose a IP address |
DHCP Operation | 4 phases |
DHCP Operation DORA | Discover, Offer, Request & ACK |
DHCP Request | Client selects 1 server & announces its choice via IP broadcasting |
DHCPv6 | DHCP for IPv6 |
Distributed DNS servers | To look up information that's done by translation |
DNS | Domain Name System |
DNS Belgium | .be, .vlaanderen, .brussels |
DNS Caching | DNS client keeps local DNS cache of recent name2address translations |
DNS client | hostnames are automatically converted to IP addresses by your OSs built-in DNS client |
DNS Database | Database consisting of resource records |
DNS namespace | Full name of device formed starting at the bottom of the hierarchy & then adding name of each level higher domain & by separating all names by a point |
DNS Naming System | Using DNS query & DNS response messages |
DNS pharming | DNS Server responding with wrong IP address, causing the Internet traffic of unsuspecting user to reach another computer (the attacker's) |
DNS Protocol | Client/server Protocol of application layer |
DNS server | Software to accept DNS queries & reply with DNS responses |
DNS spoofing | AKA DNS cache Poisoning |
DNS zone | DNS name space split into several consecutive portions |
DNSSEC | DNS data signed by owner of data using private/public key |
DoH | DNS over HTTPS |
Domain | Unit that's part of an organizational unit (companies, schools, organizations) |
Domain hierarchy | Root Domain > TLDs > SLDs > subdomains |
Domain name | name of a domain |
Dynamic (dynamic) IP address | IP address automatically assigned |
Dynamic routing | Automatically via routing protocols exchanging information between routers |
EIGRP | Enhanced Interior Gateway Routing Protocol |
Fixed (static) IP address | IP address manually assigned by admin, never changing |
Forward lookup | translation from hostname to IP address |
FQDN | Fully Qualified Domain Name - The full name |
Gateway of last resort | Creating default static route |
Global Routing Prefix | What ISP assigns to customer |
gTLDs | Generic top-level domains |
GUA | Global Unicast Address |
hextets | 16bits = 4 hexas |
Host name | Name of a device |
Hosts file | file where name2address translations were kept in early years of the internet |
ICANN | Internet Corporation for Assigned Names and Numbers |
Important resource record types | MX , A, AAAA, NS, CNAME, PTR record |
Installation of DHCP server (location) | DHCP server can be installed on a computer but also on a router |
Inter-VLAN routing | Modern networks are segmented using VLANs that correspond to different IP subnets → computers belonging to different VLANs can't communicate with each other without the intervention of a Layer 3 device that provides the necessary routing |
Inter-VLAN routing techniques | Legacy inter-VLAN routing, router on a stick, L3-switchi using SVIs |
Interface ID | 64 bits (when using prefix /64) |
IP | Internet Provider |
IP header | IPv4 : 20 bytes, IPv6: 40 bytes |
IP packet | IP header & IP payload |
IP payload | Data with variable length |
IPv4 embedded address | Used for transition from IPv4 to Ipv6 |
IPv6 address | Global unique IP address version 6 |
IPv6 GUA structure | Subnet bits aren't taken from the Interface ID, but are part of the network prefix which is recommended to be /64 <--> in IPv4 the subnet bits were 'borrowed' from the host ID |
ISP | Internet Service Provider |
L | Directly connected local interface IP host address |
L3 switch using SVIs | Uses mulit-layer L3 switch with a SVI for each VLAN |
LAN | Local Area Network |
Lease time | Obtained IP addresses are valid only for certain period |
Legacy inter-VLAN routing | Uses router with physical interface for each VLAN connected to a switch --> not scalable |
LLA | Link-local address |
Local host | Host within same network |
Loopback address | ::1/128 |
Management VLAN | Used to access control of the switch |
Migration techniques | Dual stack, Tunneling, Translation |
MNO | Mobile Network Operators |
Multicast address | Used to deliver IP packet to all network interfaces belonging to the corresponding multicast group |
Multilayer switches | Switch that offers L2 functionality & at least L3 functionality such as routing |
MX record | refers to mail server of the domain (MX = mail exchange) |
NAPT | Network Address & Port Translation |
NAT | Network Address Translation |
Native VLAN | VLAN that's used by default for 'untagged' traffic |
Nested NAT | NAT after NAT |
Network Prefix | Global Routing Prefix + subnet |
Next hop | Via which other router to reach these networks |
NIC | Network Information Center |
NS record | Refers to authoritative name server |
O | Dynamic routes which were automatically added to routing table y using routing protocol (OSPF) |
OSPF | Open Shortest Path First |
Out of what may a DNS zone consists? | 1 single DNS domain OR 1 DNS domain & several subdomains for which it's responsible |
prefix length | Number behind slash |
prefix notation | Where the Ipv6 address is indicated |
Private IP address | Not routable on the internet, duplicates possible in different networks |
PTR Record | Refers to hostname (for reverse lookup) |
Public IP address | Routable on the internet, each one is unique |
R | Dynamic routes which were automatically added to routing table y using routing protocol (RIP) |
RA message methods | SLAAC only, SLAAC & Stateless DHCPv6, Stateful DHCPv6 |
RA messages | Router Advertisement messages |
Registrars | Companies that can register domain names |
Remote host | Host in another network |
Resource records | consisting of few fields: type, TTL, name, dates, etc. |
reverse lookup | translation of IP address to hostname |
RIP | Routing Information Protocol |
RIPng | RIP next generation |
Root Domain | Nameless & sometimes represented by "." |
Routed port | Pure L3 interface (like physical interface on CISCO IOS router) |
Router | L3 device (network layer), used to connect networks, Forwarding packets to correct interface |
Router on a stick | Uses router with only 1 physical interface to connect to a switch --> still 2 devices necessary |
Routes to directly connected networks | These routes are automatically created during configuration of the interfaces of the router |
Routes to remote networks | These routes can be entered either manually (by network admin) or automatically (by routing protocol/DHCP) |
RS message | Router Solicitation message |
S | Static route was manually configured by admin (for remote networks): Statistical routes: routes added manuallly to routing table |
SARR | Solicit Advertise Request Reply |
SLAAC | Stateless Address Autoconfiguration Address Configuration |
SLDs | Second-level domains |
Static routing | Manually by network admin itself |
Stub networks | Networks that are only accessible via single router (sub router) which has only 1 neighbour router (like most home networks) |
Sub router | Single router |
subdomains | e.g. ti --> ti.howest.be |
Subnet ID | 64 bits, Global Routing Prefix |
SVI | Switch Virtual Interface |
Switch | L2 device, used to create networks, Forwards frame to correct port |
Tagged Port/Trunk Port | Carries frames for multiple VLANs |
temporary IPv6 address | Temporary global IPv6 address |
TLDs | Top-level domains, ( sgTLDs, ccTLDs, ARPA) |
Translation | Translation from IPv4 or IPv6 & vice versa |
TTL field | Time To Live |
Tunneling | Encapsulation of IPv6 i IPv4 packet |
Types of DNS lookup | Forward & reverse lookup |
Types of VLANs | Default, data, native, management, voice VLAN |
Unicast address | Used to deliver an IP packet to a single network interface (6 dfferent types) |
Unique local address | range fc00::/7 to fdff::/7 |
Unspecified address | :: |
Untagged Port/ Acces Port | Carries frames for single VLAN |
Verisign | .com, .net, etc. |
VLAN | Virtual Local Area Network |
VLAN switch port types | Untagged Port/Access Port, Tagged Port/Trunk Port |
VLAN tags | Added to each frame on the trunk to identify the VLAN each frame belongs to |
VLAN Trunks | P2P connection between 2 network devices supporting more than 1 VLAN |
Voice VLAN | Using VoIP |
VoIP | Voice over IP |
WAN | Wide Area Network |
WHOIS database | Central database of domain names |