Chapter 3 - Understanding Basic Network Security Flashcards
Connectivity Protocols
TCP UDP IP ICMP ARP NDP
Encryption Protocols
SSH SCP SSL TLS IPSec
SSH
Acronym : Secure Shell
Function : Used by Secure Copy (SCP) and Securite File Transfer Protocol (SFTP)
Port TCP 22
SCP
Acronym : Secure Copy Protocol
Function : Send encrypted files over network
Port : TCP 22
SSL
Acronym : Secure Sockets Layer
Function : Secure HTTP as HTTPS with certificates
Used by : HTTPS, SMTP, LDAP, LDAPv2
Port : TCP 443 with HTTPS, TCP 465 with SMTP, TCP 636 with LDAP
TLS
Acronym : Transport Layer Security
Function : Designated replacement for SSL
Used by : HTTPS, LDAPv3
Port : TCP 443 with HTTPS, TCP 636 with LDAP
IPSec
Acronym : none
Function : Encrypt IP traffic. Works with IPv4 & IPv6. Used in Tunnel mode with VPN connections.
Main components : Authentication Header (AH) + Encapsulation Security Payload (ESP)
Port : Internet Key Exchange (IKE) with UDP 500
Application protocols
HTTP HTTPS FTP SFTP FTPS TFTP Telnet SNMP NetBIOS LDAP Kerberos Microsoft SQL Server RDP
IPv4 classes
Class A : 0.0.0.0 - 127.255.255.255
Class B : 128.0.0.0 - 191.255.255.255
Class C : 192.0.0.0 - 223.255.255.255
IPv6 benefits over IPv4
Significantly larger address space
IPsec built in (everything encrypted)
DNS zones
A : host record (IPv4) AAAA : host record (IPv6) PTR : pointer record (opposite of A record) MX : mail exchanger CNAME : canonical name / alias
DNS ports
TCP 53 : zone transfers
UDP 53 : name resolution
Ports ranges
0 - 1023 : well-known ports
1024 - 49151 : registered ports
49152 - 65535 : dynamic and private ports
IPv4 primary methods to handle traffic
Unicast : one-to-one traffic
Broadcast : one-to-all traffic
Firewall rule general format
PPSDP Permission Protocol Source Destination Port
NAT benefits
Public IP addresses don’t need to be purchased for all clients
NAT hides internal computers from the internet
NAT modes
Static NAT
Dynamic NAT
OSI model layers
"All people seem to need data processing" "Please do not throw sausage pizza away" 1. Physical 2. Data Link 3. Network 4. Transport 5. Session 6. Presentation 7. Application
Physical layer
Devices : Cables, hubs
Protocols : Ethernet, cabling protocols
Data Link layer
Devices : switches
Protocols : MAC, ARP, NDP, VLANs
Network layer
Devices : Router, Layer 3 switch
Protocols : IPv4, IPv6, IPsec, ICMP
Transport layer
Protocols : TCP, UDP
Application
Devices : proxies, application-proxy firewalls, web application firewalls, web security gateways, UTM security appliances
