Net330 Quiz 2 - ConnorEast/Tech-Journal GitHub Wiki
Hierarchical Internetworking Model
Access(Edge Layer) [Layer 2]
Handles communication between devices on the same network + Broadcasts.
Handles: VLANS
Switching Platforms
Laptops/Computers
Distribution Layer [Layer 3]
The main goal of this layer is to facilitate routing, filter and Qos Policy execution
Handled by Multi-Layer Switched
handles cabling to ACCESS from core
Switches
Core Layer [Layer 2]
High Speed, High Redundancy Forwarding, doesn't require significan configuration
Handles Dumb Switches;
Handles data flow from border to distribution.
Border Layer [Layer 3+]
This section connects to ISP's for internet access.
Routers,
Firewalls / Security Devices,
Load Balancers,
Interior Routing with OSPF
Routing VS Forwarding
Routing: The proccess of creating and maintaining a routing table of the internal network topology [hop Count, Shortest path, IP, et;all]
Forwarding:The proccess of using the routing table to transfer packets from one device to another. In other words, we are executing routing via forwarding.
IP Routing - Longest Match
Longest Match is used to determine the most specific route possible for proper forwarding. An item on the 192.168.1.0 network would rather use 192.178.1.0/24 then 192.178.0.0/26
IP Forwarding
Upon packet recieval the destination address is inspected and matched via interface information to determine internal or external usage. The routing table is checked to confirm longest-match before the route is chosen and the item is forwarded based on the next-hop mac address or it is forwarded to the default route.
Forwarding Table: [Layer 2] Destination Network, Next Hop, Mac Address, Outgoing interface
IGB VS EGP
Interior Gateway Protocol [IGP]: Used when attempting to create a internal routing table. Used in controlled enviornments. Examples: OSPF & rip
Exterior Gateway Protocol [EGP]: Used when connecting to the outside network IE: Internet/ISP. Routes traffic through external Autonomous systems [AS].
Dynamic IGP Types
Distance Vector Protocol: DVP's rely almost solely on hop count to determine the correct path accrossed a network. Example: RIP
Link State Protocol: LSP's rely on finding the shortest path possible, IE transfer speed. Example: OSPF
OSPF Basics
Not enough information to understand the concept of basic.
OSPF Area
OSPF Area simply states, if your on a network located in Area X; any and all traffic must be confirmed against the X table. Routers on Area 0 can only locate other items on Area 0. Area 1 would be inaccessible to every area but 1.
Exterior Routing with BGP
Autonomous System
A collection of IP routing prefixes under a single administrative entity which has a defined routing policy.
AS Numbers
An IANA assigned identification number, up to 32 bits, for use in BGP routing.
BGP General Operation
BGP Neighbors, known as peers, are manually configured between routers. It features the creation of a TCP session on port 179. Every 60 seconds a 19-byte keep-alive message is sent out to maintain connections. BGP is unique as it uses TCP.
BGP Peering
Peers must have their ISP’s linked using an external link
Allows for multi-homed networks,
Advertisements for your AS will occur through peers.
Other Routers pick the best “path” to your network
PATH vector VS DISTANCE vector protocol
Path Vector uses the entire route to ensure packets make it to their destination. See BGP Best Path Algorithm below
BGP Best Path Algorithm
BGP route selection uses the following attributes: Weight, Local, Shortest Path, Lowest Origin, Lowest Multi-Exit Discriminator
General configuration Steps
enable BGP
Set the AS number on your router
Set the neighbor port IP and the AS number
Confirm same configuration has been done on the opposing AS.
Set the internal network space if applicable.
Test Network traffic and confirm network functionality between both AS
Network Address Translation (NAT)
NAT definition:
a layer 3 protocol which focuses on translating and remapping private to public ip spaces. Nat primarily is used in conjunction with VPNs. The headers change would be that of the layer 4 & 3 layer headers.
NAT use cases:
Security: Reduces front facing applications while allowing for internal to external IP conversion and conversations.
VPN Connections
Network remapping
Ip Masquerading
Types of NAT
Static Nat: maps a single IP to a public IP.
Dynamic Nat: Maps multiple ip address to a pool of public ip addresses
Pat [Port Access Translation]: Allows for individuals to be able to access internal resources through the use of the companies IP in conjunction with the port number for said resource.
Zoning
Reasons to Segment a network
Reduces BroadCast Traffic
Decreases traffic to internal networks
Application of least priviledge
Least privilege
Individuals should have the bare minimum permissions / access in order to complete their jobs. Someone in sales doesn't need access to the entirety of the companies financial documentation
Router ACLs as Defense
Used for blocking traffic from broadcasts, DHCP, Multicast, Private IP’s, Internal Network IP’s, Unencrypted protocol [Telnet, FTP, rsh, echo, MS Networking].
Layer 4 firewalls
Layer 4 firewalls Allows for internal and external network traffic over only specific ports.
Layer 7 Firewalls
Layer 7 Firewalls allows for you to block specific URL's/DNS sites. This can be good for decreasing traffic to risky channels
Network Zoning Goals
simplification of the rule set for ease of Admin access, Services, and User Access.
improves troubleshooting capabilities, incident response, and improves intrusion prevention and monitoring.
