Troubleshooting Tools

Question 1

What are WiFi Analyzers?

Answer 1

WiFi Analyzers are used for WiFi surveys, analyzing the wireless coverage and allow to detect unwanted overlapping of access points.

Question 2

What is the IP Configuration command for Windows and the most important arguments?

Answer 2

ipconfig:
- ipconfig /all
- ipconfig /release (release the current assigned local IP address)
- ipconfig /renew (request a new IP address)

Question 3

What is the legacy IP Configuration command for Unix/OSX and the most important arguments? (5)

Answer 3

ifconfig:
- ifconfig -a
- ifconfig eth0
- ifconfig -v
- ifconfig eth0 down/up
- ifconfig eth0 192.168.1.200 netmask 255.255.255.0

Question 4

What is the newer IP Configuration command for Unix/OSX and the most important arguments (5)?

Answer 4

ip:
- ip a
- ip addr add/del 192.168.1.200 dev eth0
- ip link set eth0 down/up
- ip link set dev eth0 address :Mac address:
- ip link set dev eth0 promisc on

Question 5

What is the command to see current connections and what are the most important arguments?

Answer 5

Its netstat, the most important arguments are:
all: -a
no name resolving: -n
show PID: -o
statistics: -s
show routes: -r

Question 6

What is the command to show the arp cache and what are the most important arguments?
And how long is the TTL of cached arp entries?

Answer 6

Its arp, the most important arguments are:
all: -a
delete an entry: -d (ip address of entry)
add static entry: -s (ip address) (mac address)

The time to live is 21.600 seconds.

Question 7

How to change the nameserver and the record type with nslookup in interactive mode?

Answer 7

Change nameserver: server (nameserver)
Change record type: set q=A,MX,CNAME etc (for UNIX its set type=MX)

Question 8

What are the most important ping arguments?

Answer 8

-n/-c: Number of pings for Windows/Linux
-t: Infinite pings on windows
-6: force IPv6

Question 9

What are the 5 troubleshooting steps with ping?

Answer 9

1. Ping a reliable website like google.com
2. Ping a reliable IP like google DNS
3. Ping Default Gateway to check LAN connectivity
4. Ping your local IP
5. Ping the localhost IP to verify network card & drivers

Question 10

What are the important nmap arguments?

Answer 10

-sn: ping scan to see which hosts in a network are live
-sS: SynScan
-sV: Version Scan
-O: OS scan
-p: only scan specific port

Question 11

What are the 3 basic network device commands and what are they for?

Answer 11

1. show interface: Statistics for the interface
2. show config: Current configuration
3. show route: Information on routes

Question 12

What are the 4 more advanced network device commands and what are they for?

Answer 12

1. show MAC address table: Displays the MAC address to port mappings on a Cisco switch.
2. show ARP: Displays the ARP table mapping IP addresses to MAC addresses.
3. show VLAN: Shows VLAN configurations including VLAN IDs, names, statuses, and associated ports.
4. show power: Displays PoE power settings and usage per switch port.

Question 13

What are the 2 discovery protocols and what are the 3 main benefits?

Answer 13

• Link Layer Discovery Protocol (LLDP)
• Cisco Discovery Protocol (CDP)

The benefits are:
- Network Security
- Network Performance
- Network Reliability