Page 19 - Security+ (635 notes by Nikkhah)

Infrastructure Security

Packet-filtering firewalls

282- These firewalls permit or block access to specific ports or IP addresses.
283- In the Allow by Default policy, all traffic is allowed except that which is specifically denied.

284- In the Deny by Default policy, all traffic is blocked except that which is specifically
allowed.

285- Well-known port numbers range from 0 to 1023.

286- User ports (registered ports) range from 1024 to 46,151.
287- Dynamic/private ports range from 46,152 or 65,535.

Application layer firewalls
288- These firewalls examine the entire packet to allow or deny traffic.

289- They are much slower than packet-filtering firewalls.
290- Proxy servers use these firewalls to provide application layer filtering.

Stateful Inspection Firewalls

291- These firewalls actively monitor and inspect the state of network traffic.

292- They are faster than application layer firewalls.
293- They can dynamically open and close ports as needed by applications.

Routers

294- Routers connect two segments of an internetworkand workat Layer 3 of the OSI model.
295- They use a table of IP addresses to forward network traffic.

296- Administrators build static routing tables in small networks.

297- Distant vector and link states are dynamic routing protocols.
298- Routers support Access Control Lists (ACLs) to determine which IP packets should be

allowed or blocked.
299- Dynamically built routing tables are prone to spoofing and eavesdropping.

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