Domain 4: Communications and Networking Flashcards
- What is Internet/Internetwork layer in the TCP/IP model? What 2 basic functions does Internet protocol perform? What is this layer called in OSI model?
responsible for sending packets across potentially multiple netorks. Does routing.
Hosting addressing/id & packet routing.
called OSI Layer 3.
71 What is the Transport Layer in the TCP model? What is it called in the OSI layer? How is data sent?
It has the port numbers. It has the basic data channels that applications use for task specific data exchange. It is called OSI layer 4.
data is sent via TCP or UDP (connectionless)
71 What is the application layer? What is it called in the OSI model?
Protocols used by applications for providing user services or exchanging data like HTTP FTP SMTP, CHCP, IMAP.
Distinguishes between user and support protocols.
It is called the OSI layer 5, 6 and 7.
72 What is MAC address or BIA? EUI
Media Access Card or Burnt In Address. A unique identifier on a network card. Extended Unique Identifer
72 What is a MAC48? What is a EUI 64?
MAC 48 is the original design. first 24 are maufacter identifier. last 24 are unqiue and idenrify the host.
EUI64 use 24 bit for manufacturer and last 40 are qunique annd identify the host.
48bit mac’s ipv6 can be modified into 64 bit macs by adding FF:FE to the device ID.
72 What is IPv4?
connectionless protocol to use on packet switched networks.
Operates on best effort delivery model, it doesn’t guarantee delivery, it doesn’t assure proper sequening or avoidance of duplicate delivery. We added other protocols on top of IP to ensure those. TCP protocol made to fix these.
72 Ports 3 known.
What are ports like?
0-1023 mostly used for protocols.
0124-49151 Mostly used for vendor specific applications
49152-65535 can be used for anything like web browsers.
Ports are like apartment numbers.IP is like your address.
72 Specific ports (2 digits) 6 of them
20 TCP FTP data transfer
21 TCP FTP Control
22 TCP/UDP Secure Shell SSH
23 TCP Telnet unencrypted text communications
25 TCP Simple Mail Transfer protocol SMTP also 2525
80 TCP/UDP HTTP use 8008 8080
72 Specific ports (3 digits) 6 of them
110 TCP Post Office Protocol v3 POP3
137 UDP NetBIOS Name Service, use for name registration
138 TCP/UDP NetBios datagram service
143 TCP Internet message access protocol IMAP
443 TCP Hypertext Transfer protocol over TLS/SSL or HTTPS
3389 TCP/UDP Microsfot Terminal Server RDP
73 What is a socket?
1 set of IP and Port. like 192.168.0.6:510291.
TCP has 2 sockets. UDP only uses 1 socket.
73 IANA? RIR?
Internet Assigned Numbeers Authority. It is a department of ICANN (Internet corporation for assigned names and numbers)
RIR Regional Internet Registry regions:
1 AFRINIC
2 ARIN
3 APNIC
4 LACNIC
5 RIPE NCC
73 What are 3 types of ip traffic?
- unicast: one to one traffic. Client to server. Use promiscouous mode on specific clients network cards.
2 Multicast: one to many (predefined)
3 Broadcast: one to all (on LAN network)
73 what are the 3 broadcast traffic types?
1 Limited L3 Broadcast: Used 255.255.255.2555 broacast ip address. routers do not pass it.
2 Limited L2 Broadcast: FF:ff:ff:ff:ff. routers do not pass .
3 Direct broadcast: sent to anyone logically connected to thesame network. It doesn’t need to be physically behind the same network.
74 Ipv4? What about private ipv4? What are 3 exception addresses for private ipv4?
Made of 4 Octets and into 32 bit integer binary.
private ipv4 have 3 ranges, 10.xxx, 172.xx., 192.168.xx… . Loopback addresses 127.0.0.0/8 , Link-local 169.254.0.0/16 , Broadcast 255.255.255.255
74 Ipv4 What is a NAT? What are 2 NATs?
Network Address Translation. It was a band aid solution to extend the depletion of IPv4 addresses.
Static NAT translate 1 to 1 public ip to private ip.
Pool NAT still 1-1 but pool was avaiablle to all clients
74 What is a PAT?
Port Address Translation. Also called NAT overload or One to Many.
74 What is CIDR?
Classless Inter Domain Routing also called slash notation. You logically segment them out. /24 is 256. /32 is 1. /0 is 4.29 million. /24 is most common and 254 is usable for hosts. first 0 and last 255 can’t be used. But with newer tech, only 255 is not usable since it is a broadcast address.
74 What is classful IP network?
Early in the internet used inefficient IP addresses. Networks had 16 million + IPs.
74 What is in the IP headers?
Version: IP version 4, IHL: lenght of IP header, QoS (quality of service), ID (used for IP fragmentation AND priority of the service, TTL (to prevent routing loops, protocal, Source and Destination IP addresses, MTU (maxium transmission unit , 1500 bytes , if packet exceeds that size a router may fragment into smaller packets.
75 What does IPv6 header contain?
Version: IP v6 (4 bits),
Traffic Class/Priority , old QoS 8bit , Flow Lable/QoS management 20 bits, Payload Lenght 16bits, Next Header 8bits, TTL/Hop Limit 8bits (this is to prevent briding loops, once it hits a router, it is decremented by 1), source IP address 128bits, Desitnation IP address 128bits. MTU Maximum Transmission Unit normaly 1500 bytes. if a packet exceeds a size it will be fragmentsed into smaller packets.
75 IPv6
128bit hexadecimal numbers (use 0-9 and a-f) 16 options. You don’t need NAT or PAT. 8 groups of 4 hexadecimals. IPSec is built in. hard to read so remove all 0s and add ::
75 How do you change MAC address for ipv6?
shimmy fffe (used in EUI64) into EUI 48 address. from 00:fa:22:52:88:8a into 00:fa:22:ff:fe:52:88:8a.
then to 20:fa:22:ff:fe:52:88:8a modifed identifiers to allow development oftuture tech that can take advantage of interface identificers with universal scope.
75 How do you add MAC address to IPv6
If you network prefix is 2001:0000:0000:00b8, you add this in front of the mac address. Like 2001:0000:0000:00b8:20fa:22ff:fe52:888a. to 2001::b8:20fa:22ff:fe52:888a (internet). Link local address for local only change 2001 to fe80.
76 What is ARP Address Resolution Protocol? What is RARP?
Translates IP addresses into MAC addresses. It is always trusting. Victim to ARP cache poisoning attack usually with Default Gateway. ARP sends out a request to the network “does any know the physical address for this ip address “ as multicast. A switch or phsycial device responds in unicast. but an attacker can respond. RARP=Reverse ARP is ued by diskless workstations to get IPs. It sends out this is my MAC address, then here is your IP address.