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1 Network+ > IP and Routing > Flashcards

IP and Routing Flashcards

1
Q

What technique allows you to send TCP and UDP data flows in a single combined transmission over a network?

A

Multiplexing - allows you to combine multiple application/transport streams into one transmission.

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2
Q

Which protocol TCP or UDP is connection orientated?

A

TCP - reliable delivery method as ACKnowledges packets are received and can be resent if needed (error recovery) and reordered.

The receiver gets what you send. Guaranteed delivery/signed for.

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3
Q

Which protocol has flow control?

A

TCP

Flow control - receiving device can tell sender/source device to slow transmission down if it can’t handle the speed or speed up the transmission.

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4
Q

Which is faster TCP or UDP?

A

UDP - no overheads or waiting for ACKnowledgement from receiving device.

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5
Q

What is included in every IP packet to send the data to the right app?

A

Port Number.

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6
Q

What is an IP socket?

A

A combination of an IP address and a port number which together identify the socket for a specific process/service.

IP:Port

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7
Q

What range of port numbers are non-ephemeral?

A

0-1023 are permanent/non-ephemeral port numbers but this is just a rule of thumb and not set in stone. (you can pick any port number for anything if you’d like.)

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8
Q

What are client side ports from 1024-65,535 also known as?

A

Ephemeral/Temporary/Changing ports although this is just recommended and it’s just a number. TCP ports are separate from UDP ports e.g. TCP/80 is a different port to UDP/80!.

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9
Q

What type of IPv4 addresses are in the range 127.0-127.255

A

Loopback address range 127. all devices have a self-loopback address to self reference. This is an easy way to see if your local IP stack is working.

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10
Q

How many bits are in an IPv4 address?

A

32-bits (8x4) 4 octets.

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11
Q

How many bits are in a IPv6 address?

A

128-bits, 16 octets

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12
Q

What is a link-local address? What can it communicate with?

A

A link-local address (e.g. APIPA - 69.254 range) is an IP that allows the device to ONLY connect to other devices on its subnet. It doesn’t allow forwarding by routers.

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13
Q

How many bits are usable for host addresses in a Class B subnet mask?

A

16 bits (2 octets).

255.255.0.0 (class b subnet mask)

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14
Q

How many bits are reserved for the network address in a Class A subnet mask?

A

8 bits (1 octet) 255.0.0.0 (class a subnet mask)

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15
Q

How many bits are reserved for hosts in a Class C subnet mask?

A

8 bits (1 Octet) 255.255.255.0 (Class C subnet) Demarcation (separation marker) point after the first 24 bits reserved for network address before the host portion of the mask begins.

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16
Q

Is CIDR classful or classless?

A

CIDR - Classless Inter-Domain Routing - removed the restrictions of classful subnet masks.

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17
Q

What is the subnet mask of a CIDR notation of /16? E.g. 172.68.0.0/16

A

255.255.0.0 because /16 in CIDR is 16 bits for the network portion of the subnet mask.

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18
Q

What is the subnet mask of a CIDR /24? E.g. 192.168.1.44/24

A

255.255.255.0 = CIDR /24 because 24 bits (3 octets) are used for the network side of the subnet mask.

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19
Q

What would the CIDR notation be of the following subnet mask?

255.0.0.0

A

/8 in CIDR as the first 8 bits are the network part of the mask.

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20
Q

What are the first and last addresses (0 & 255) reserved for in a subnet?

A

The first address/value of 0 is reserved as the network address and the last value/address of the subnet is reserved as a broadcast address. Therefore there are only 254 useable host addresses not 256 because 0 is reserved for the network address and 255 is reserved for the broadcast address.

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21
Q

In the Magic Number Subnetting method what number would be an interesting decimal octet value/the INTERESTING OCTET from 0, 232, 255?

A

232 would be the Interesting Octet as any octet value in a subnet mask other than 255 or 0 is considered the INTERESTING OCTET which you then subtract from 256.

256-232=24 so there would be 24 hosts available on that subnet!

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21
Q

What is the formula to work out how many host addresses there are?

A

(2 to the power of the number of 0’s/host bits)-2 = the amount of available hosts per subnet.

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21
Q

What is subnetting?

A

Changing the subnet mask to suit your purpose - defining how many subnets and hosts per subnets you want.

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22
Q

In the IPv6 address 2001:0db8:85a3:0000:0000:8a2e:0370:7334 what can be removed to compress it (make it more human readable)?

A

The leading 0 in the 2nd and 7th 16-bit group can be removed.

The 0’s in the 4th and 5th 16-bit groups can be compressed to “::”

So it becomes: 2001:db8:85a3::8a2e:370:7334

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23
Q

What does NAT64 (6 to 4 ONLY) do and what DNS service is often used in conjunction with it?

A

NAT64 translates IPv6 into IPv4 addresses, often used with DNS64 which translates the DNS requests.

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24
Q

What is a routing table?

A

A routing table is a list of stored network paths to destinations. When a packet is received by a router/routing device the destination IP address is compared to the routing table and a next best hop/step/router IP address is decided on.

Decides the next best hop on a data packets path across a network.

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25
Q

What is static routing?

A

Manually setting a network pathway/route between devices in a network.

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26
Q

What are some pros of static routing vs dynamic routing?

A

+Easy to configure in a small network.
+More secure as you know the exact route your packets follow - fewer attack vectors - less chance of MITM attack.
+No overhead/routing protocols needed which makes it quicker.

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27
Q

What are some negatives of static routing?

A

Very hard to scale in large networks.
Risk of human error - if you configure something wrong data won’t reach destination.
No automatic redundancy/can’t adapt on the fly to network failures - if a hop on a pathway fails then rip.

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28
Q

What is dynamic routing?

A

Method where routers automatically update their routing table/list based on network changes - by being in constant communication with other routers exchanging routing information. Provides redundancy by changing route if a device/hop on a path has stopped responding.

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29
Q

What are the benefits of dynamic routing?

A

+No manual management or configuration of routes
+New routes are populated automatically on the fly e.g. if a new device is added a new path is formed
+Much more efficient, can provide load balancing
+Provides redundancy as an alternate route can be automatically switched to if a device on a primary path goes down
+Highly scalable to large networks due to the automation

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30
Q

What are the drawbacks of dynamic routing?

A

-Requires initial setup of routing protocols
-Some routing protocol overhead for data packets (bloat)

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31
Q

What is a commonly used dynamic routing protocol?

A

EIGRP updates - Enhanced Interior Gateway Routing Protocol are used to exchange routing information across a network to update each routers routing table (add new paths that those routers can’t see themselves).

Different routing protocols decide on the best route using different parameters e.g.:
-is the route available or not
-how many hops away would the route take you

OSPF (Open Shortest Path First), BGP (Border Gateway Protocol) are also commonly used routing protocols.

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32
Q

Are routing protocols proprietary?

A

Some routing protocols are proprietary (not all). Which means they will only work on CISCO devices/routers etc.

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33
Q

What does cost refer to in OSPF routing?

A

Cost is a combined value based on the network route/paths throughput, speed and reliability. The lower cost (faster and more reliable route) is always chosen/prioritised by OSPF routing protocol. (Open Shortest Path First).

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34
Q

What does the OSPF routing protocol prioritise routes based on?

A

Open Shortest Path First (OSPF) is a routing protocol designed to prioritise routing table paths based on the speed of the route/cost (throughput, round-trip time and reliability).

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35
Q

What is the main benefit of the BGP - Border Gateway Protocol routing protocol over the OSPF - Open Shortest Path First routing protocol?

A

The BGP (Border Gateway Protocol) can connect multiple different networks (autonomous systems/AS) together whereas the OSPF is used in a single Autonomous Systems/network owned by the organization/company.

OSPF - private company routing protocol (more secure and faster CONVERGENCE (reaction speed to network changes))
BGP - world wide, communal routing protocol

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36
Q

Which routing protocol updates faster in reaction to network changes; BGP or OSPF?

A

OSPF has faster convergence - update speed in response to a network change.

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37
Q

If there are multiple routes on a routing table to a specific IP/destination then which one of the routes is chosen?

A

The most direct route (fewest hops) wins.

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38
Q

If there are two identical IP routes to a subnet and one has an administrative distance of 254 and one has an administrative distance of 0 which is selected to be used?

A

The route with an administrative distance of 0 is chosen. The lower the administrative distance the higher the priority of the route type.

0 = the lowest Administrative Distance as it is a DIRECT (Local) connection/pathway and 255 is the highest Administrative Distance being an “unknown” route/pathway type.

1=static route

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39
Q

What is FHRP - First Hop Redundancy Protocol and what does it provide?

A

It is a way of having multiple devices (routers generally) act as default gateways to provide redundancy/prevent downtime by putting a VIP - Virtual IP Address as the default gateway address as a hop in front of the primary router that is switched to the redundant router/s in case the primary router goes down.

Like a proxy IP for the gateway device meaning that a redundant gateway can be setup both using the same VIP.

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40
Q

What are subinterfaces?

A

Subinterfaces are multiple virtualised interfaces within one single physical interface (e.g. a single switch port). They are configurable and are used to segment/split networks, create VLANs, reduce how many physical cables are needed.

E.g. one physical interface 1/1 can be subdivided into 3 subinterfaces:
-suberinterface 1/1.1
-suberinterface 1/1.2
-suberinterface 1/1.3

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41
Q

What is the networking technology called trunking?

A

A way of carrying traffic for multiple VLAN’s over a SINGLE PHYSICAL connection/network link/network path between two end points.

Single network cable to carry traffic for multiple VLANs instead of needing one physical network cable for each ones traffic.

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42
Q

What network protocol prevents network loops on Ethernet networks?

A

Spanning Tree Protocol (STP) - prevents network loops by identifying the shortest/optimal path and BLOCKING redundant paths/loops by changing the PORT STATE to Blocking.

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43
Q

What are the 5 possible port states for STP?

A

5 States of Ports for STP:
Blocking = prevent loops by dropping frames.
Listening = monitors BPDUs (Bridge Protocol Data Units) to determine the network topology.
Learning = learns MAC addresses WITHOUT forwarding the data/addresses.
Forwarding = forwards frames/allows data frames to pass through the port and is fully operational
Disabled = not used in the STP process

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44
Q

What is the “root bridge” used in STP?

A

Root port is the central reference point/root/source for the spanning tree - all paths and points in the network are calculated relative to it.

The root bridge that all connected network topology (network paths) are calculated from relatively.

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45
Q

What is a bridge/network bridge?

A

Network bridge/bridge is HARDWARE that connects multiple LAN’s together. i.e. bridging the gap between them

46
Q

What is path cost?

A

Path cost = a metric/measure used by STP to determine the shortest/most efficient path to the ROOT BRIDGE (bridge with lowest BridgeID/BID = bridge priority + MAC address).

Path costs are defined by the 802.1D standard:
10 Mbps: 100
100 Mbps: 19
1 Gbps: 4
10 Gbps: 2

47
Q

What IEE standard defines the default path costs of different cable/connection speeds in a topology?

A

802.1D standard defined
10 Mbps: 100
100 Mbps: 19
1 Gbps: 4
10 Gbps: 2

48
Q

What is a ROOT PORT (RP)?

A

Root Port (RP) = a SINGLE port on every non root switch that has the lowest PATH COST to the ROOT BRIDGE.

(The fastest route to return traffic to the root bridge).

49
Q

What is a DESIGNATED PORT (DP)?

A

Designated Port (DP) = a single port PER NETWORK SEGMENT (Layer 2 portion/no routing) that FORWARDS frames AWAY from the ROOT BRIDGE.

50
Q

What is a BLOCKED PORT (BP)?

A

Blocked Port (BP) = stops traffic being forwarded from/through it to prevent loops. STP has a single optimal/active path open between network devices at any one time.

51
Q

Does STP provide redundancy if a path fails/disconnects?

A

Yes. STP recalculates the network topology and reactivates a BLOCKED PORT to maintain connectivity/provide redundancy.

Happens when STP detects a link failure using regularly exchanged BPDU’s (Bridge Protocol Data Units).

52
Q

What is the latest version of STP (802.1w)?

A

Rapid STP (RSTP/802.1w) is the latest version of STP with much faster convergence (time taken to reach to a change/failed link and provide a new route) than original STP 50 seconds -> 6 seconds.

RSTP is backwards compatible with STP.

53
Q

What is port bonding/link aggregation?

A

Technique used to merge multiple network physical connections/multiple physical ports to appear to the network as one. This allows for load balancing across the interfaces, more bandwidth and provides redundancy.

54
Q

What is an MTU?

A

MTU - Maximum Transmission Unit = the biggest IP packet size that can be sent across a network pathway without fragmenting.

Fragmenting slows transfer speeds down by adding overhead and if you lose a fragment then you lose the ENTIRE IP packet.

55
Q

What are Jumbo Frames and why use them?

A

Jumbo Frames are Ethernet frames (layer 2/MAC/data link) that are bigger than 1500 bytes of payload.

By using Jumbo Frames less headers/overhead is needed per data byte transferred. This improves data transmission efficiency and lowers CPU loads (as less frames to unpack/process).

All Ethernet devices in the network path must support Jumbo Frames.

56
Q

If APIPA only works for IPv4 addresses what is the IPv6 equivalent?

A

SLAAC - StateLess Address AutoConfiguration - is the IPv6 way of self-assisgning an IP address automatically without needing a DHCP server. It allows the device to communicate globally (globally scoped) whereas IPv4 APIPA addresses can only communicate within their subnet (local scope).

57
Q

What is the purpose of Neighbour Discovery Protocol (NDP) in IPv6?

A

NDP replaces IPv4’s ARP and ICMP protocols for IPv6 addresses. NDP is multicast (vs IPv4 broadcast which is limited to the local subnet) which is one to many devices including those in a global scope (provided there are forwarding multicast routers).

NDP makes IPv6 networks self-sufficient and more streamlined than IPv4.

58
Q

Why is NDP (IPv6) faster/more streamlined than IPv4 ARP?

A

NDP is faster/more streamlined as it uses MULTICAST (one-to-many pre-defined multicast addressed group of network devices) instead of BROADCAST which is used by ARP that is locally scoped and bloats the network by sending to every device on the network instead of just those devices that need the information (that multicast sends to).

59
Q

Does NDP support SLAAC?

A

Yes, NDP supports SLAAC by enabling the router to advertise a prefix and allowing devices to automatically create their own IPv6 address.

60
Q

What process within NDP in IPv6 prevents duplicate IP’s on a network/IP conflicts?

A

DAD - Duplicate Address Detection - is a NDP process that scans for and prevents Duplicate IP addresses on a network thereby preventing IP address conflicts.

61
Q

What is the purpose of the DAD mechanism within NDP?

A

DAD = process that scans for and prevents Duplicate IP addresses on a network thereby preventing IP address conflicts.

62
Q

Is ff02::2 the all-routers multicast address?

A

Yes, ff02::2 is the all-routers multicast address.

So if you send a message to ff02::2 all routers on the local network will receive it.

63
Q

What is the RS/RA two step process for configuring stateless IPv6 address, that replaces the DORA (IPv4) 4-step process?

A
  1. RS = Router Solicitation - message for all routers on the local network (discovery) sent to the all-routers multicast address (ff02::2) to get the network’s prefix and default gateway/configuration information.
  2. RA = Router Advertisement - response message from router to new device on local network containing the:
    -Network prefix/subnet mask (e.g. 2001:0db8::/64) that the device can then use to configure it’s own stateless (self-assigned) IPv6 address
64
Q

What is the equivalent of a network prefix (IPv6 CIDR notation) in IPv4?

A

Network prefix is just the IPv4 subnet mask equivalent for IPv6 (expressed in CIDR notation e.g. 2001:0db8::/64).

65
Q

What is a gateway of last resort?

A

Gateway of last resort = is a static configured fallback path that packets are routed to from other devices if they can’t find a path for the packets. This prevents the packets simply being dropped/lost and the gateway of last resort can then forward it on its way using its huge routing table/generally including a path out the the internet or wider network.

66
Q

What is a physical link between two devices?

A

Physical link = hardware connection between two network devices (switches/routers, etc). So cables or the radio waves of a wifi connection are PHYSICAL LINKS.

67
Q

What is the range of Class B private IPv4 addresses available?

A

Class B Private IP range: 172.16.00 - 172.31.255.255

(all other 128 - 191 Class B addresses are Public IP’s)

68
Q

What is the range of Class C private IPv4 addresses available?

A

Class C Private IP range: 192.168.0.0 - 192.168.255.255

(all other 192 - 223 Class C addresses are Public IP’s)

69
Q

What is the range of Class A private IPv4 addresses available?

A

Class A Private IP range: 10.0.0.0 - 10.255.255.255

(all other 1 - 126 Class A addresses are Public IP’s)

70
Q

What does the number of a CIDR notation represent?

A

CIDR notation represents how many bits are reserved for the subnet mask.

E.g. /24 means 24 bits (3*8 octets) are reserved from the IP address for the network address. So /24 = shorthand for 255.255.255.0 Class C IP address with 254 possible hosts.

So /16 = 2 octets reserved for the NID portion of the address. Aka 255.255.0.0 Class B IP address with 65,000 possible hosts.

/8 = 1 octet reserved (8 bits) = 255.0.0.0 = Class A IP = 16.7 millions possible hosts

71
Q

What is the range of IP addresses for multicast?

A

Multicast (one-to-many) IP range: 224.0.0.0 - 239.255.255.255

224 - 239

72
Q

What is the broadcast IP address?

A

Broadcast on 192.168.30.255/24 (one to ALL)

73
Q

Loopback/localhost address range?

A

Loopback address (host to itself): 127.0.0.0 - 127.255.255.255

74
Q

What CIDR notation (bits reserved for the subnet mask) creates networks with only 2 hosts per network?

A

/30 CIDR notation creates 64 useable network ID’s with 2 useable hosts on each.

This is useful for site to site network where there are only ever going to be two sites.

75
Q

What is IP routing?

A

IP Routing = The exchange of data packets between networks based on the destination IP address of the packet using routing tables (store network paths/routes) to find the best path by using a routing protocol:
OSPF, EIGRP, BGP routing protocols are used to decide on optimal path for stability, speed or efficiency

76
Q

What is 2^10?

A

2^10 = 1024 JUST REMEMBER IT

77
Q

How many bits is an IPv6 address?

A

128 bits = IPv6

32 bits = IPv4

78
Q

What are the first 48 bits of an IPv6 address used for?

A

First 48 bits = Global Routing Prefix/NID

79
Q

What do the second 16 bits (one octet) after the first 48 (4 octets) represent?

A

Second 16 bits (one octet) in an IPv6 address represents the subnet ID.

SUBNET ID (4th Octet/8)

80
Q

How many bits per octet in an IPv6?

A

16 bits per octet denoted by 4 hexadecimal characters. Each character (0-9, a-f) represents 4 bits each.

81
Q

What do the last 64 bits of an IPv6 address represent?

A

The last 64 bits (4 octets) of an IPv6 address represents the Interface ID (generally based on the MAC address of the Interface).

82
Q

How many times can you use :: to compress blocks of 0’s in an IPv6?

A

You can only use :: once as if you use it more than once you wouldn’t know which :: represented how many blocks/octets of 0’s.

E.g. ::2.::1 can’t know if it’s like 0000.0000.2.0000.0000.1 or 0000.2.0000.0000.0000.1 (something like that).

83
Q

Compress this IPv6: 2001:0db8:0000:0000:0000:0000:0000:0001

A

Uncompressed IPv6: 2001:0db8:0000:0000:0000:0000:0000:0001
Compressed = 2001:db8::1

84
Q

What does an octet of 0000 compress down to in an IPv6?

A

0000 compresses to 0 unless there is a consecutive octet of 0000 (and it’s the first time in the address) so:

0000: 0000 becomes :: but 2:0000:1 becomes 2:0:1
and
0000:0000:fe90:0000:0000:0000:32be:0123 becomes ::fe90:0:0:0:32be:123

85
Q

What is a Global Unicast Address?

A

Global Unicast (Uni= one to one) Address = IPv6 address that is publicly routable used for communication OUTSIDE of a LAN e.g. globally.

86
Q

What is a Unique Link-Local Address (ULA)?

A

Unique Link-Local Address FD00/8 = internally routable only (not-publicly routable/can’t be accessed over the internet) address used within a LAN.

87
Q

What is the IP address range for an IPv6 Link-Local address?

A

FE80::/10 is the link-local address range for IPv6, this is the equivalent of APIPA for IPv6. Used to communicate with itself.

88
Q

What is an IP address in the range FE80::/10?

A

FE80::/10 is a Link Local Address (replacement for APIPA).

89
Q

What is the IPv6 for loopback address in IPv6?

A

::1 = Loopback address (system only checking address) the IPv6 equivalent to 127.0.0.1 in IPv4. Used to test network function/NIC function/protocol stack without the need to reach other devices/networks.

90
Q

What are the benefits of IPv6 over IPv4?

A

More IP address combinations available - so doesn’t require NAT (Public to private IP translation)
Faster routing/more efficient with simplified/smaller header information.
More secure than IPv4 as it uses IPsec as mandatory (IPv4 IPsec security suite is optional.

91
Q

What does RIP (Routing Information Protocol) use for a metric/measure of the best path to take?

A

RIP uses HOP COUNT as the measure of the best pathway (RIP is an old distance-vector protocol).

92
Q

What is the primary purpose of routing protocols?

A

Routing protocols determine the best path for data to take from a source to a destination across a network by discovering and sharing routing information in the network (i.e. what paths there are).

93
Q

Do classful routing protocols support subnets?

A

No. Classful routing protocols (e.g. RIPv1) do NOT support subnets.

94
Q

What’s the maximum number of hops RIP supports?

A

RIP - Routing Information Protocol supports a maximum of 15 hops and is used for small networks because of this and its slow convergence time.

95
Q

What is convergence in routing?

A

Convergence is the the process in which all network routers update and sync their routing tables to build a complete layout of the network and can then decide on the best routing paths between devices.

Convergence takes time and slow convergence can lead to routing loops or lost/dropped packets during the process.

96
Q

What does OSPF stand for and is it good for large networks?

A

OSPF - Open Shortest Path First routing protocol is highly scalable and flexible meaning it’s great for large networks as it has a fast convergence time. OSPF only updates when network topology changes (a path changes) thereby reducing unnecessary network load from say repeated updates at set intervals.

97
Q

What does EIGRP (Enhanced Interior Gateway Routing Protocol) use to determine optimal network paths?

A

EIGRP uses bandwidth, delay, reliability and load to determine optimal routes.

EIGRP uses load balancing and is suitable for medium-large networks.
Only partially updates when changes occur so whole network map doesn’t need to be reconverged.

98
Q

What is administrative distance in routing?

A

Administrative distance (AD) is a metric that routers used when there are routes provided by multiple different routing protocols to determine the trustworthiness of them and thereby decide which to use.

A LOWER AD value indicates a more preferred route. With 0 being the king.

99
Q

Is a lower or higher administrative distance value (AD) a more preferred route by routers?

A

Lower AD = more preferred route to use to forward packet to destination.

100
Q

What is VLSM?

A

Variable Length Subnet Mask (VLSM) = classless subnets/CIDR notation = more efficient than class-based subnets which have fixed bits/sizes of the subnet mask (e.g. Class A, B and C subnet masks).

101
Q

What is classFULL addressing?

A

Classful addressing = using Class based subnet mask sizes/fixed amount of subnet bits based on Class A/B/C subnet. This is more inefficient as it defines a rigid IP address block (A/B/C /8/16/24 /16 million/65,000/256) which often leads to wasted/unused/left over IP addresses. E.g. most companies don’t need 256 IP addresses per network.

102
Q

What’s the formula to calculate number of available subnets?

A

subnetworks = 2 to the power of subnet bits available

E.g.
/24 has 24 subnet bits so 2^24 = 16 million subnets available in a class C /24 IP

103
Q

Formula to calculate number of hosts/IP addresses per subnet?

A

hosts available per subnet = 2 to the power of host bits available -2 (1 reserved for network ID and one for broadcast domain)

E.g. a /27 subnet has 32-27= 5 host bits available so 2^5 = 32-2 = 30 hosts available for each subnetwork.

104
Q

What are the three types of NAT?

A

Static NAT (one internal address-to-one external address)

Dynamic NAT (many internal addresses to many external addresses) - rarely used as it can limit internet access

Port Address Translation (PAT) many internal address to one external/public address - most commonly used.

105
Q

Is NAT used by IPv4 or IPv6 or both versions?

A

NAT is generally only used by IPv4 as it has a relatively small/exhaustible range of IP addresses. NAT adds latency/another step in the routing process.

106
Q

What is Dynamic NAT?

A

Dynamic NAT = each internal/private network device gets assigned one of many external/public IP addresses on a first come first served basis. This is very rarely used as public IP addresses are costly and the small pool gets exhausted quickly.

107
Q

What is PAT - Port Address Translation?

A

PAT - Port Address Translation is a type of NAT whereby many internal/private IP addresses are converted to and from one external/public IP address. This is the most common type of NAT used to access the internet.

Aka overloading NAT.

108
Q

What is Static NAT?

A

Static NAT is a one internal IP address being translated to and from one public IP address. E.g. in the case of hosting your own web server (one device with one public facing IP and one private internal IP).

109
Q

What is SIP?

A

Session Initiation Protocol (SIP) is a signalling protocol that establishes, manages and terminates real-time communication sessions like VOIP.

SIP manages VOIP sessions.

Skype SIP.

110
Q

What does a CNAME record map?

A

CNAME (Canonical NAME) record maps one domain name to another. E.g. www.google.com has a CNAME to map it to google.com so when www.google.com is searched the DNS resolves/converts it to google.com (the primary domain).

111
Q

What does a PTR (Pointer) record do?

A

Pointer record (PTR) is used for reverse DNS lookup - maps IP address to domain names. Often used for security checks, e.g. that emails come from a safe/legitimate domain.

PTR is the reverse of A/AAAA records.

112
Q

What is a hosts file?

A

Hosts file is local DNS resolution file - maps domains/hostnames (part of a domain) to IP addresses. Hosts file is checked first (before DNS server) and if no record found in Hosts file then DNS query is sent out to DNS server.

113
Q

What is the range of IPv4 Class D addresses?

A

IPv4 D = multi-D - multicast addresses - 224 - 239.255.255.255
224 - 239.255.255.255 = Class D IPv4 address range (no private ranges for D and E)

114
Q

What is the range of IPv4 Class E addresses?

A

Class E = 240 - 255.255.255.255
Experimental range for testing purposes only. (no private address range for D and E)

1 Network+ (11 decks)

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