Chapter 2 System Fundamentals Flashcards

Question

IP Address 150.215.017.009 If this NW is divided into 14 subnets, identify the subnet mask and subnet address

Answer 1

For the Subnet Mask, the first 16 bits (network address) are all set to 1. The host address is determined by how much space is needed for the 14 subnets. 16 is the closest bit to turn on to accomodate the 14 subnet addresses, so 256-16 = 240 making the subnet mask 255.255.240.0 As for the subnet address, it becomes the inverse, 255.255.16.0

Answer 2

Convert everything to binary CIDR defines the # of bits that are on, so out of the 32 bits in an IP address, the first 24 from left to right are 1s To find the NW address, we want to add the IP address AND Netmask. NW Address = 192.168.1.0 To find the broadcast address, we want to peform utilize the OR operator between the NW address & the inverse of the Netmask Broadcast address = 192.168.1.255

Answer 3

Bits are 1s and 0s Nibbles are 4 bits A byte is 2 nibbles

Answer 4

allows computers to send data out the door while simultaneously identifying that data by category These ports range from 1-1024 1. FTP 20-21 2. SSH 22 3. Telnet 23 4. SMTP 25 5. WINS 42 6. DNS 53 7. HTTP 80, 8080 8. Kerberos 88 * Computer NW authentication protocol, authenticates request for a service in a computer NW 9. POP3 110 10. Portmapper-Linux 111 * Makes RPC Calls 11. NTP 123 12. RPC-DCOM 135 13. SMB 139 14. IMAP 143 15. SNMP 161, 162 16. LDAP 389 17. CIFS 443 18. Syslog 514 19. Secure LDAP 636

Answer 5

These ports are the ones that have been identified as usable by other applications running outside of the user's present purview. Registered ports range form 1025-49151. 1. WINS 1512 * Windows Internet Naming Service - maps NetBIOS names to IP addresses; solves problem of NetBIOS name resolution in routed environments 2. Socks5 1080 * routes NW packets between client & server through an application proxy which is different from a normal proxy; An example would be when using HTTP proxy, you are actually fowarding an HTTP request, and the HTTP proxy server then performs the request on your behalf 3. Nessus Server 1241 4. SQL Server 1433, 1434 5. Citrix Applications 1494, 2598 6. Oracle Listener 1521 7. Citrix Mgmt 2512, 2513 8. RDP 3389 9. IRC 6662-6667 * Internet Relay Chat - Application layer protocol that facilitates transfer of messages in the form of text

Answer 6

a server that sits between client applications, such as between a web browser and server

Answer 7

free ports available for use by TCP, UDP requests made by an application These ports range from 49152 - 65535

Answer 8

database that contains the translated names to IP addresses that can be queried by any DNS-aware applications The internet root servers, or top level servers, contain addresses of the DNS servers for all top-level domains, .com, .org, etc. Each top-level server contains a DNS database of all names & addresses in that domain Local NWs isolated from the Internet may use their own domain name systems through use of DNS mgmt SW. These names are typically same as those used by internet implementation **Hacking** - if an attacker manipulates DNS, in modern day environments, applications may not work without DNS present & functioning; Ex. Microsoft AD wouldn't work without DNS present or accessible **Active Directory** - special purpose database for windows that handles a large # of read & search operations

Answer 9

**Routers** work at **layer 3** by directing packets & connecting different NWs Routers also used as gateway between different types of NWs, such as on different NWs or IP ranges or NWs that don't understand each other's protocols i.e. can't just jam a fiber-run T1 connection into client computer & have fast NW; NIC (NW interface card) is nto capable of speaking the same language as the outside connection, Routers bridge that gap and allow different protocols on different NWs to communicate Routers use **NAT** (NW Address Translation) allows internal NW clients to share a single public IP address for access to the outside world. A router has **two interfaces:** one for outside world & one for internal NW The public side is assigned a public IP address purchased from Local ISP; The internal side is connected to the local intranet, which contains all of your internal IPs & protected resources; internally, you can create your own IP schemes. When an internal client makes a request to an outside resource, the router receives the traffic & sends it out the public side with its public IP safeguarding the client's internal IP address NAT is great for security and also conserves IP addresses cutting cost for ISP

Answer 10

**Switches** creates **multiple broadcast (multicasted) domains & collosion domains for each port, it delivers data or frames based on HW addresses (MAC Address)** of the destination computers/devices; considered **Layer 2 device** (few modern switches operate Layer 2 & 3) MAC or Media Access Control addresses are permanent identifiers burned into each NIC by manufacturer; Broken down into 6 pair hexadecimal, i.e. c0-cb-38-ad-2b-c4, the 1st half (3 pair) identifies vendor, 2nd half identifies NIC or device **Finding Mac Address:** cmd command for windows --\> ipconfig/all for linux: ifconfig

Answer 11

Hubs are similar to swtiches but are considered dumb devices, they operate at **layer 1** physical layer, they forward the data they receive, no filtering or directing of traffic which is why they are considered layer 1

Answer 12

A broadcast domain allow traffic to be broadcast to all connected nodes ARP requests (Address Resolution Protocol), which are sent to the NW to resolve HW addresses, are an example of broadcast domain Collosion domains are NW segments in which traffic sent will potentially collide w/ other traffic; In a collion domain, traffic will not be sent to a broadcast, it will collide w/ other traffic on the wire So what this means is when you throw your little penetration testing laptop on a wire & connect to a switch, no matter how promicious your NIC is, your captured traffic will be limited to the collosion domain In current modern day technology, sniffing a wi-fi NW allows you to capture traffic from all of its clients; not limited to particular switchport CD **Hubs:** similar to switches but are dumb devices that make no decision in data direction or addressing

Answer 13

These are the device deliberately put in place to prevent unauthorized access; only as effective as their configuration, & configuration is only as effected as the admin creating them **Proxies** work at the **Layer 7 application layer**, & can be used for caching & filtering of web content. Itwork in the middle of the traffic scene. acts as an intermediary between internal NW client systems & outside untrusted entities; prevent client from communicating directly with outside source **Benefits of Proxies** - protection of internal client systems, reducing exposure & risk Acts as middleman, protecting clients from themselves Speed up browsing by caching frequently visited websites & resources

Answer 14

Includes proxy firewalls; filter outgoing traffic requests & verify legitimate traffic; firewall attacks intended to circumvent rather then head-on assult; Mainly broken into these categories 1. **Packet Filtering** * Packet filtering firewalls look at the header information (such as IP address or port) of packets to determine legitimate traffic; inspects packets at most granular level possible & improving traffic efficiency 2. **Stateful packet filtering (keeps records of interaction)** * determine legitimacy based on state of connection from which traffic originated 3. **(web) Application proxies** (mentioned in last card, client to outside untrusted entities)

Answer 15

both used to cover your tracks, keep a low profile **IDS** - intrusion detection system - detect any suspicious NW activity & notifies admin, passive in nature; similar to a burglar alarm that alerts you, but doesn't stop the burglar **IPS** - intrusion prevention system - proactive & preventive, senses potential malicious activity on NW & takes steps to prevent further damage and thwart further attacks

Answer 16

securing a NW is a holistic process where the entire system as a whole is more important then the individual tools that create the system breaking into a NW however is a focused process, you have to consider each part of the system & plan accordingly; could sabatoge an entire NW if you take the right steps in preparing

Answer 17

**Archive** - used to compress files to use less space or to organize several files into one for portability or storage **Archive Bit** - used in certain OSs, it indivates whether or not a file needs to be backed up

Answer 18

**backup -** making extra copies 1. **Full backup -** full back up resets the archive bit of all files & backs them up accordingly 2. **Differential backup** - backs up all changed files since last successful full backup. Does not reset archive bit; creates one large file and fully restores off of latest differential backup (full is not needed) 3. **Incremental Backup** - backs up all changed files since last full back up OR since the last incremental; does not reset archive bit; creates several small backup jobs; last full back up + incrementals are needed to restore 4.

Answer 19

Windows systems respond to port scans, but Linux does not!!!