1.	Using the OSI model, which layer has the responsibility of making sure that the packet gets where it is supposed to go?

2.	What is the subnet mask, network address and broadcast address for the following address: 123.65.47.62/22?

3.	What command is used to show all open ports and/or socket connections on a machine?

4.	What is NAT? What is it used for?

5.	Which IP ranges/subnets are "private" or "non-routable" (RFC 1918)?

6.	What is a packet filter and how does it work?

7.	What is a proxy and how does it work?

8.	What is ARP and what is it used for?

9.	What is the difference between TCP and UDP?

10.	What command is used to show the route table for a machine?

11. Explain asynchronous routing?

12.	What is the purpose of a default gateway?

13.	A TCP connection on a network can be uniquely defined by 4 things.  What are those things?

14.	When a client running a web browser connects to a web server, what is the source port of the connection?

15.	What is the destination port of the connection?

16.	What is SMTP?

16.	What is an SMTP relay?

16.	Give the basic scenario of how a mail message is delivered via SMTP

17.	What function does DNS play on a network?

17.	What is an A record?

17.	What is an NS record?

17.	What is an MX record?

17.	What is a PTR record?

17.	What is a DNS forwarder?

17.	What command is used to lookup DNS records?

17.	What is meant by "Reverse Lookup"?

18.	What is LDAP and what is it used for?

19.	What is a DN in LDAP?

20.	What is SSH?

21.	What is SSL?

22.	What is IDS?

23.	What is IPS?

24.	What is the difference between IDS and IPS?

25.	What is meant by the term "DOS Attack"?

26.	What is RAID?

27.	What is swap and what is it used for? 

28.	What command will show the available disk space on the Unix/Linux system?

29.	How do you determine the public and prive IP addresses, if applicable, of a Unix/Linux system from the command line?

30.	What Unix/Linux command will alter a file's ownership?

31.	What Unix/Linux command will alter a file's permissions?

32.	What Unix/Linux command will show all processes running on a system?

33.	What Unix/Linux command will show the details of a file(permissions, size, timestamp)?

34.	What Unix/Linux command would you use to list all currently loaded kernel modules?

35.	What command would you use to telnet to port 7777 on a machine with IP address 10.10.10.128?

36.	What Unix/Linux command(s) will show a system's current resource allocations?

37.	What is the Unix/Linux command to remove a directory and its contents?

38.	What is the name and location of the system log on a Unix or Linux system?

39.	What would you do to recover a lost the root password to a Unix/Linux system?

40.	What is the difference between hardlink and symlink?

41.	What happens when you remove the source to a symlink?

42.	What are some of the security risks of symlinks?

43.	Explain a hardlink

44.	Where is a filename stored?

45.	What happens when a hardlink is removed

46.	how do you know when a file is removed

47.	Write a locking function in bash

48.	What is a pre-emptive kernel, what does that mean to you?

49.	What is an atomic operation?

50.	How does a switch get a mac address?

51.	What type of packet to discover a router? 

52.	How does traceroute work?

53.	A careless sysadmin executes the following command: ```chmod 444 chmod``` - what do you do to fix this?