Misc Things to Work On Flashcards
PKI
Public Key Infrastructure:
Gives secure email exchanges & web browsing & solves the problem of having to distribute the keys ahead of time
Kerberos
Port 88: Provides secure authentication over an insecure network
No passwords sent across network; ticketing system
Domain Controller = KDC (Key Distribution Center)
If authenticated, client is issued a TGT (Ticket Granting Ticket)
RADIUS
Remote Authentication Dial-In User Service:
Centralized administration of dial-up/VPN/Wifi network authentication
Supports EAP & 802.1x
Layer 7: Client-server protocol
UDP, AAA
Doesn’t support remote access protocols
Ports: 1812, 1813 (Authentication Messages, Accounting Messages)
Proprietary Ports: 1645, 1646 (Authentication Messages, Accounting Messages)
TACACS+
Terminal Access Controller Access Control System Plus:
Port 49
Performs role of authenticator in an 802.1x network
Supports all network protocols
Cisco proprietary
TCP
Use RADIUS for cross-platform capabilities
802.1x
A standardized framework used for port-based authentication on both wired & wireless networks
Supplicant
User requesting access to the network
Authenticator
Device through which the supplement is requesting access to the network
Authentication Server
Centralized device that performs the authentication (RADIUS/TACACS+ Server)
Most modern NACs use 802.1x
Can encapsulate EAP
Packet-Filtering Firewall
Permits/denies traffic based on packet header
Firewall: Stateless Packet Inspection
Allows or denies packets into the network based on the source and destination IP address or the traffic type (TCP, UDP, ICMP, etc.).
Firewall: Stateful Packet Inspection
Monitors the active sessions and connections on a network.
The process of stateful inspection determines which network packets should be allowed through the firewall by utilizing the information it gathered regarding active connections as well as the existing ACL rules.
Clean Agent System
Utilizes halocarbon or inert gas to suffocate a fire when the system is activated
Split-View DNS
An implementation in which separate DNS servers are provided for security and privacy management for internal and external networks
“Line protocol is down”
Means that the specified interface has been correctly configured and enabled, but the Ethernet cable might be disconnected from the switchport.
Cross Talk
When a signal transmitted on one copper twisted pair in a bundle radiates and potentially interferes with and degrades the transmission on another pair
Classless Routing
A type of routing where the router uses the default route to forward traffic if no other specific routes are found
OSPF, RIPv2, EIGRP, IS-IS
Asymmetric Routing
Network packets leave via one path and return via a different path
Asymmetric routing doesn’t cause any routing issues necessarily, but they do cause issues with dropped packet flows by our security devices like firewalls and unified threat management systems
Network Interface Commands: Show Route
Displays the current state of the routing table on the device
Typically you would use “show ip route”
Displays routing protocol labels in routing table
[160/5]
160 = administrative distance
5 = routing metric (lower the better)
Show ip route 131.119.0.0
Shows metrics for the specified network
Network Interface Commands: Show Config
Displays the current system configuration on the screen
Network Interface Commands: Show Interface
Displays statistics for the network interfaces on the device
Ex: show interface ethernet 1/1
Make sure bandwidth matches cable type
Otherwise cable may be damaged or wrong type
If using a SAN, make sure MTU > 1500
Check for APIPA = DHCP issue
Check for runts, giants, & errors
Check for collisions
There should be no collisions if operating at full duplex
SDN Layers: Application Layer
Focuses on the communication resource requests or info about the network as a whole
SDN Layers: Control Layer
Uses the information from the applications & decides how to route a data packet on the network
SDN Layers: Infrastructure Layer
Contains the network devices that receive info about where to move the data & then perform those movements
SDN Layers: Management Plane
Used to monitor traffic conditions & the status of the network
Datacenter Hierarchy: Core (1st Tier)
Biggest, fastest, most expensive routers
Backbone of network
Merges geographically separated networks into one logical unit
At least 2 routers operating in redundant configuration
Datacenter Hierarchy: Distribution/Aggregation (2nd Tier)
Boundary Definitions: Implements ACLs/Filters
Define policies for network; Layer 3 switches
Needs to ensure packets are properly routed between subnets
Datacenter Hierarchy: Access/Edge (3rd Tier)
Used to connect to all endpoint devices
Legal Hold
A notification sent from an organization’s legal team to employees instructing them not to delete electronically stored information (ESI) or discard paper documents that may be relevant to a new or imminent legal case
Securing SNMP
Follow least privilege
Always use v3
Combine with whitelisting of MIB
Use authPriv on your devices
Includes authentication & encryption features
Need to use a newer network device that supports cryptography
Strong SNMP passwords
Use ACLs to prevent MIB access (strict control)
Segregate SNMP traffic onto a separate management network or VLAN
Keep system images & software up-to-date
ACL Tips
Block incoming requests from internal/private loopback & multicast IP ranges
Block incoming requests from protocols that should only be used locally
Block all IPv6 traffic
Or allow it to only authorized hosts/ports if using IPv6
Cisco ACLs
Www = HTTP (port 80)
Domain = DNS (port 53)
HSRP vs. VRRP
HSRP = 1 active, 1 standby VRRP = 1 active, many standby
Coax Limitations
Coaxial
100Mbps, 500 meters
Twinaxial
10Gbps, 5 meters
Newer: 100Gbps, 7 meters
Networking Tools: Attenuation
Copper = cable certifier
Fiber = fiber light meter
Networking Tools: Interference
Copper/Fiber = Spectrum analyzer
Networking Tools: Decibel Loss
Copper = cable certifier, cable analyzer
Fiber = fiber light meter
Fiber: Dry vs. Wet Cleaning
Dry Cleaning: Best for dust/dirt on connector
Wet Cleaning: Best for oil residue (ex: fingerprints)
Parabolic vs. Directional Antennas
Parabolic works best outside (greater signal strength)
Directional is better for inside use
CSU/DSU
Used to terminate the digital signals at a customer’s demarcation point
Demarcation Point
The entrance facilities where your WAN connection will enter your building
Teredo Tunneling
Used to give IPv6 connectivity to a computer with only an IPv4 connection
Route Believability Metrics
Directly Connected = 0 Statically Configured = 1 EIGRP = 90 OSPF = 110 RIP = 120 External EIGRP = 170 Unknown/Unreachable = 255
Link Lights: Activity Light
Status of link while in use
Off = no link or connection
Orange = connection established
Blinking orange = data activity occurring over link/connection
Link Lights: Speed Light
Off
Slow, 10Mbps
Orange
100Mbps
Green
1Gbps
IPv6: Dual Stack
Devices are able to run IPv4 and IPv6 in parallel
Subinterfaces
A virtual interface created by dividing one physical interface into multiple logical interfaces
RTO
Recovery Time Objective:
Time and service level within which a business process must be restored after a disaster to avoid unacceptable consequences
RPO
Recovery Point Objective:
Interval of time during a disruption before data lost exceeds the BCP’s maximum allowable threshold or tolerance
QSFP vs. QSFP+
QSFP = 40Gbps QSFP+ = 41.2Gbps
Neighbor Discovery Protocol
Used by IPv6 to learn the layer 2 addresses on the network
Router Solicitation - used by hosts
Router Advertisement - used by routers
Neighbor Solicitation - used by nodes
Neighbor Advertisement - used by nodes
Redirect - Routers informing host of better first-hop routers
GRE
Generic Routing Encapsulation: VPN/Tunneling System Site-to-site private connection Allows any protocol Not secure on its own
mGRE = multipoint GRE (can be combined with DMVPN)
RFC1918
Private IP addresses reserved
- 0.0.0/8
- 16.0.0/12
- 168.0.0/16
DNS Record: SOA
Start of Authority:
Indicates which Domain Name Server (DNS) is the best source of information for the specified domain
Connectionless Protocols
ICMP, UDP, IP, IPX
Connection-oriented protocols:
TCP, SSH, SSL
VTP
VLAN Trunking Protocol:
Shares VLAN information to all switches in a network. VTP enables you to configure the VLAN on a VTP server for centralized configuration and management. When you make a change to the VLAN configuration on a VTP server, the change is propagated to all switches in the VTP domain
SOW
Statement of Work:
A document that outlines all the work that is to be performed, as well as the agreed-upon deliverables and timelines
SAN: iSCSI Switching
Set MTU to 9000 on each of the participants in the SAN
VLAN Hopping Methods
Double tagging
Switch spoofing