N10-009-Section_6_Bonus Flashcards
List the 4 layers of the TCP/IP Stack
Application, Transport, Internet, Link
Describe the Application layer (TCP/IP)
Represents data users, encode and controls the dialog (Maps to the Application, Presentation, and Session layers of the OSI)
Describe the Transport layer (TCP/IP)
Supports communication between end devices across a diverse network (Maps to the Transport layers of the OSI)
Describe the Internet layer (TCP/IP)
Provides logical addressing and determines the best path through the network (Maps to the Internet layer of the OSI)
Describe the Link layer (TCP/IP)
Controls the hardware devices and media that make up the network (Maps to the Data-Link and physical layers of the OSI)
SONET
Backbone of the internet, as opposed to Ethernet as a standard, SONET works with higher level systems / Tier 1 internet
Define ARP
Address Resolution Protocol - If a computer has an IP address for another computer but doesn�t have the MAC, it will send out a broadcast to ask for the MAC associated with that IP so it can send frames to that computer. ARP resolves MAC addresses from IP addresses
What command can you run to see the stored ARP data on a computer (Windows)
arp -a
Whats the Broadcast Address for ARP
FF:FF:FF:FF:FF:FF
Define IANA
Internet Assigned Numbers Authority - They made up the classes of IP addresses and hand IP ranges out to RIR (Regional Internet Registries)
Define RIR
Regional Internet Registries - organizations in charge of managing internet/ip standards for large sections of the world (North America, Asia, etc,,,) - RIRs give IP addresses to ISPs
What is ::1
Loopback address for IPv6
Static NAT (SNAT)
Static NAT is a one-to-one mapping between a private IP address and a public IP address. This means that each private IP address is permanently mapped to a specific public IP address. One-to-One Mapping: Each private IP is always mapped to the same public IP, regardless of when or how many times the private device communicates with external networks.
Dynamic NAT (DNAT) (pooled NAT)
Dynamic NAT automatically maps a private IP address to a public IP address from a pool of available public IPs. Unlike Static NAT, the mapping is not fixed and can change every time the private device sends traffic.
Port Triggering
Can trigger a different port to forward when receiving on a defined port. Example: FTP, you can set port forwarding to trigger ports 20 and 21 when a request is sent on port 20. Conditional Port Forwarding. Closes the forwarded port after the session is finished
Cisco IOS
Cisco CLI
What is IGMP?
Internet Group Management Protocol - Works on the Internet layer of the TCP/IP model. Used in Multicast, a video server will assign the data to a multicast address. 1 video stream can enter a network and the router will propagate the data to all computers who are requesting the stream.
What is in the IGMP Packet?
Source Address, Group Address, Checksum, Type - The group address is a multicast address that all computers on a network, who are requesting the video, can use to receive the stream.
What is tracert (Windows) or traceroute (Linux)
Command that allows you to check all the hops from your router to another
What is Pathping
Same as tracert but it uses a different protocol so it can succeed where tracert might fail
What is Wireshark
A protocol analyzer
Netstat
Command that will show the active connections on your computer
Netstat -n
Presents the results numerically (no dns names, just IP addresses)
Netstat -b
Shows the executable for each connection
Netstat -bn
Netstat with b and n switches
Netstat -a
Shows all active ports, even those without connections
Netstat -r
Shows the local routing table - nothing to do with netstat - same as route print
Microsoft IIS
Internet Information Service
Apache
Open source web server software (vs IIS)
What is the purpose of the Anonymous account on an FTP Server
This account allows public access to the FPT server
Traditional TLS (In Email Encryption)
Used the standard unencrypted ports to start the connection then switched over to the encrypted ports. IMAP 143 -> 993, POP 110 -> 995, SMTP 25 -> 465 (or 587)
TLS
TLS (Transport Layer Security) is a cryptographic protocol designed to provide secure communication over a computer network. It ensures:
STARTTLS
Still TLS, but at no time was it in an unencrypted state - All 3 protocols worked on 587 (although you may find questions that state it uses 465)
SSH uses an authentication key
SSH uses an authentication key
What is SNTP?
Simple Network Time Protocol - Uses UDP to synchronize time - Uses Port 123
What is Stratum 0 (Network Time)
A level of time keeping devices that keep near perfect time - Atomic clocks, GPS, Radio Waves
What is Stratum 1-15 Server/Clients (Network Time)
Servers that synchronize within a few milliseconds of the stratum 0 devices, and so on and so forth
Exhausted DHCP scope
You’ve run out of addresses in the set scope (192.168.1.2-254) - Sometimes this can be because the lease time is set for too long and a bunch of devices still have leases that are no longer connected to the network
Net view
Lists what computers your computer can see within the workgroup
Net user
Lists who you are in terms of the network - what computer you are on and what the account name is
Net view \<computer_name></computer_name>
Lists the shares that the designated computer has available
Net use
Can map a drive - net use w: \server\share
Net share
Share a resource - net share nickname=C:\users\zach.lee\myfolder
Net accounts
Lists settings for account - password expiration and length info
Net start
Lists the network based services that are running on the system - can also start a stopped service
Net stop
Turn off a service - net stop “world wide Web Publishing Service”
NetBIOS
NetBIOS (Network Basic Input/Output System) is a software interface and networking protocol that allows applications on separate computers to communicate over a local area network (LAN). It was developed in the 1980s and is often used in Windows networks. This service also resolves names across a network, computers can communicate by name
LLMNR
The new NetBIOS - Linked Local Multicast Name Resolution
Windows Name Resolution
On a domain, its done through DNS, but off domain, there are options like NetBIOS and LLMNR
Nbtstat -n
Lists what the computer’s name is and if it is registered under said name
Registered Names
Windows systems keeps track if its name and propagates it through the network
Nbtstat -c
Lists the cache of names your computer knows about - doesn�t keep the cache for long
Nbtstat -a (system_name)
Like running nbtstat on another computer - shows its name information
Nbtstat -r
Lists stats on what the computers been doing on the network - what computers it’s been talking to
Nbtstat -R
Uppercase R - clears remote cache table
Nbtstat -RR
Uppercase RR - Rebroadcasts your registered information out on the network
Dynamic DNS (DDNS)
A service that automatically updates DNS records. If you have a device or server with a DHCP address, its difficult to map this to a domain name cause it might change. DDNS will keep track of these changes so its not an issue. There is a DDNS client on the device or router that will update the DDNS server if its IP address changes.
Ipconfig /displaydns
Lists the DNS cache on a computer
Nslookup
Name saver lookup - Most DNS servers are locked down and wont respond - You can get the answer to “Is this a DNS server?” and “is it running”? - Know what the output of this command looks like
DIG
Domain information groper - doesn�t come with windows - Needs software like EzDig - Can test DNS servers and query them for information - Most DNS servers are locked down and won’t respond - You can get the answer to “Is this a DNS server?” and “is it running”?
CIA of security
Confidentiality, Integrity, Availability
Non-repudiation
Non-repudiation in network security is a method to ensure that a user or a system cannot deny the authenticity of their actions or communications. It provides proof of data integrity and authenticity, typically through mechanisms like digital signatures and encryption, making it possible to verify the origin and integrity of data.
Symmetric Encryption
A method of encryption in which data can be encrypted and decrypted with the same key - To decrypt you need an algorithm and the key
Asymmetric Encryption
Uses a public key and a private key - Public key to encrypt, private key to decrypt. (Key pair) - An algorithm is used to create a private and public key pair. The two are tied together mathematically, but cannot be derived from each other. Each side of the encryption has their own pair. Each side gives the other a copy of their public key. When sending info to side B, Side A can use Side B’s public key to encrypt the data, then send it to side B, then B can decrypt with its private key
Hash
An algorithm that will transform a chunk of data to a fixed size value (no matter the length of the original data) - This can be used to verify that data has not changed or is the same. Take the input data and run it through the Hash, then match the output of the hash
List types of common Hashes
MD5, SHA1 and SHA2 (SHA2 = SHA256, and more)
Authentication Attributes (AAA)
Something you do (Signature), Something you exhibit (typing speed), Someone you know (Signed Cert from a trusted source), Someone you are (Location)
MAC (AAA)
Mandatory Access Control - Label is put on the resource and that defines what you can do with the resource
DAC (AAA)
Discretionary Access Control - Owner can be added to the resource - other people can be readers and writers
Radius provides AAA (Just a note)
Radius provides AAA
Radius Supplicant
The device - Computer / phone
Radius Client
The Access Point that has been setup for Radius
Radius Server
The server through which authentication is done
Radius Database
Part of the radius server but might not be the radius server itself. Could be a domain controller the radius server checks
TACACS+ User
The person signing in
TACACS+ Client
A router / switch
TACACS+ Server
The server through which authentication is done
Kerberos
Designed to do Authentication for local area networks. Kerberos is a Microsoft Product and a copy of Windows Server must be bought to use it.
Key Distribution Center
When a computer is setup to be Domain Controller it automatically becomes a Kerberos KDC. KDC consists of 2 services, Authentication service and Ticket Granting Service
TGT
Ticket Granting Ticket - Given to a computer after authentication by the Authentication Service (Computer is now authenticated, but not authorized), the computer then timestamps the TGT and gives it back to the Ticket Granting Service, TGS timestamps it again and sends a Token back to the computer. The token can be used to authenticate to other computers on the network
EAP
Extensible Authentication Protocol - Allows multiple authentication methods to interplay with each other. Kerberos is mostly used over wired networks, PPP is used over wireless.
EAP PSK
EAP Pre-shared key - Common key everyone uses to login
PEAP
Protected Extensible Authentication Protocol - uses standard username and password
EAP MD5
EAP-MD5 (Extensible Authentication Protocol - Message Digest 5) is an authentication method used in network security, particularly in wireless and PPP (Point-to-Point Protocol) environments. It employs the MD5 hashing algorithm to provide authentication for a user or device attempting to connect to a network.
EAP TLS
EAP-TLS (Extensible Authentication Protocol - Transport Layer Security) is a highly secure EAP authentication method widely used in wireless networks and VPNs. It leverages TLS (the same protocol used for HTTPS) to provide strong mutual authentication between clients and servers.
EAP TTLS
EAP-TTLS (Extensible Authentication Protocol - Tunneled Transport Layer Security) is an EAP authentication method that enhances security by encapsulating client authentication within a secure TLS tunnel. It provides flexibility in how user credentials are transmitted while maintaining robust encryption.
Single Sign On
Single password and username used to authenticate through multiple devices and resources - Managed by AD (or something else)
Federated Systems
Systems on the same domain - the same domain means they have a trust relationship with each other
Unsigned Cert
No third party vouching for the cert - it�s a cert created in house - Can be used if there is another level of trust somewhere, like “you work for me” so you trust the cert I generated is legit
Web of Trust
Multiple users who trust each other. Over time, there is a bunch of people who trust other people who trust other people etc� Difficult to maintain
Change the default password on switches (just a note)
Change the default password on switches
Data VLAN
Traditional VLAN
Voice VLAN
Prioritizing Voice traffic to improve Qos for voice
InterVLAN Routing
Virtualization of a Router so VLANs on the same switch can talk to each other without a separate router
You can use a router to connect between 2 VLANs (just a note)
You can use a router to connect between 2 VLANs
802.1Q
Protocol that allows trunking to happen across switches from different manufacturers - Needs to be enabled
VTP
VLAN Trunking Protocol - Cisco Proprietary - Used to automate the updating of multiple VLAN switches
Consol/Rollover/Yost Cable
Cable used to connect a computer to a switch or device. Uses the console port
Enable (Cisco IOS)
To enter privileged mode
> (Cisco IOS)
Regular mode
(Cisco IOS)
Privileged mode
Show running-config (Cisco IOS)
Gives information about the switch configuration
Show interface fa 0/1 (Cisco IOS)
Shows the information for Fast Ethernet port 1
Runts (Cisco IOS)
Packets that are underneath the required Ethernet standard amount of bytes
Giants (Cisco IOS)
Packets that are over the required Ethernet standard amount of bytes
Show route
Command that could be on a layer 2 switch or router - displays the routing table
Copy run start (Cisco IOS)
To save your configuration changes - copys the altered configuration to the running configuration
Switch Port
Cisco coined the term - a port with no IP address - to differentiate it from router ports or network card ports - Don�t work on layer 3
Root Bridge
Root switch - when switches are plugged in they negotiate based on distance to each switch which switch should be the boss
Root Guard
Solution to prevent malicious switches from being plugged in and designating themselves as the root bridge. Once the Root Bridge is established, the MAC address is cached so that all switches know if there is an imposter trying to act as the Root Bridge
BPDU Guard
Bridge Protocol Data Units Guard - Ports can be configured to only work for computers and not for other switches. This guards against another switch being plugged in. When switches are plugged in they send out BPDUs and the ports with BPDU Guard enabled, will disable themselves
DHCP Snooping
You can designate ports on a switch to know that they are connected to a DHCP server, that way if another DHCP server is plugged in the switch can detect and ignore/disable
Port Bonding / Port Aggregation
Combining 2 ports on a switch to increase bandwidth. If you have a trunk port that is overwhelmed, you can bond another port to it to help with the load
Port Bonding Setup
Create a group first, then add the ports to that group
Port-Channel
A group in a cisco switch for port bonding
Bonded ports active vs passive
One port needs to be active on one of the 2 devices (or both ports active). If both are passive it won’t work