Network

Question 1

Packet filtering fw ?

Answer 1

Layer 1-3
Classic packet filtering on access list, from top to down acl order

Question 2

Stateful filtering firewall

Answer 2

Osi L1 to 4
Check if part of new connection or part existing

Question 3

PAP

Answer 3

Password authentication protocol

Old not secure
Sending plaintext user password
Mitm attack

Question 4

CHAP

Answer 4

Challenge handshake authentication protocol

Protection against replay attack (incremental identifier and variable challenge value)
Used by PPP (point to point)
Periodically challenge remote client with three way handshake
Chap server stores plaintext password
-> so legacy

Question 5

EAP

Answer 5

Extensible Authentication Protocol
Supplicant, authenticator, authentication server

Question 6

PPP

Answer 6

Point to pount protocol used by ISP, mobile, VPN

Now replaced by PPPoE or PPPoA

Question 7

UDP port 137

Answer 7

Netbios name service

Question 8

TCP/UDP port 138

Answer 8

Netbios datagram service

Question 9

UDP port 67

Answer 9

DHCP server

Question 10

UDP port 68

Answer 10

DHCP client

Question 11

DHCP flow ?

Answer 11

DORA
Dicovery
Offer
Request
Acknowledge

Question 12

Which type of cable to avoid EMI and save cost ?

Coax
Multi-mode fiber
Copper ethernet
Simple-mode fiber

Answer 12

Multi-mode fiber