IPv4

Classes	Subnet Mask	Networks
A	255.0.0.0/8	2^7=128
B	255.255.0.0/16	2^14=~16000
C	255.255.255.0/24	~2 mln
Reserved
0.0.0.0/8
127.0.0.0/8
169.254.0.0/16
RFC1918
10.0.0.0
172.16.0.0
192.168.0.0

NAT (Network Address Translation)

DNAT: multiple private IPs translated in 1 public IP Static NAT: 1 private IP for 1 public IP PAT: each private IP is assigned to a router port on the same public IP Port Forwarding SNAT and DNAT

Remote Access

Conditional Access

MFA

Least Privilege

802.1x

Port based authentication

Patch management:

Clients (remote endpoints) and VPNs should also part of periodic reviews and patches

Virtual Private Cloud

Network security groups Subnets Internet gateway NAT gateway: logical software instance to separate subnets communications Network Peering

Wireless Network Security

PSK pre-shared key Enterprise mode (802.1X authn)

Wi-Fi Protection Access WEP - RC4 - Vulnerable WPA - TKIP - Vulnerable WPA2 802.11i - CCMP/AES - strong WPA3 - CCMP/AES, SAE - very strong

Extensible Authentication Protocol (EAP) framework to adapt to multiple authn methods (TLS, Tunnelled TLS, LEAP...)

Cellular

GSM UTMS HSPA+ 4G (LTE) 5G

SIM cards (Subscriber Identity Module) ESN: electronic Serial Number

Satellite

GPS ~27 satellites. each country or Region has its own satellite network. Mix of wired and wireless transmissions

Microsegmentation

VXLAN: encapsulation of LAN ethernet frames in UDP datagrams to route them through phisically separated LANs Containerization Multi Protocol Label Switching (MPLS)

Edge Network

DMZ CDN - edge computing devices