5.3 & 5.4

Question 2

What is an edge router?

CE vs PE

Answer 2

Uses NAT to assist external to internal internet

Customer Edge vs Provider Edge

Question 3

What do Enterprise Routers specialize in?

Answer 3

Plug in Cards for WAN
Methods for configuring VPN

Question 4

When is Static NAT useful?

Answer 4

Good for proxy servers utilizing firewalls.
.
External hosts don’t know true IP of servers, but can communicate successfully

Question 5

What is PAT for?

Answer 5

Port Address Translation.
Maps multiple private IPs to SINGLE PUBLIC ADDRESS

Question 6

How does PAT work?

Answer 6

10.0.0.101 and 10.0.0.102 want info from web.

PAT service creates two new port mappings for these requests (10.0.0.101:61101 and 10.0.0.102:61102)

Reverse engineers replies from public IP and checks the port mappings to forward to internal hosts

Question 7

How does Packet Filtering work?

Answer 7

Filters by IP
Filters by Protocol
Filters by Source/Destination

Question 8

What is packet filtering?

Does it have a state or is it stateless?

Is it secure?

Answer 8

Each packet is analyzed.

Stateless

Insecure. Malware can be spread over a sequence of packets

Question 9

What is a circuit-level stateful firewall?

Is it more or less efficient.

Answer 9

Records by session of packet transfer
.
More efficient b/c if it’s allowed at the start of the session, no need to monitor the rest of the session.

Question 10

What’s different from a SOHO vs Enterprise router?

Answer 10

Amount of sessions a router can support