Linux Final Exam

Front 1

How would you tell apache that your content is in /usr/local/www?

Back 1

In the /etc/httpd/conf/httpd.conf I would specify

DocumentRoot /usr/local/www

Front 2

How would you instruct an Apache server to listen on port 81 instead of port 80?

Back 2

Add the "listen 81" line to the /etc/httpd/conf/httpd.conf file

Front 3

How would you enable Sam to publish web pages from his ~/webiste directory but not allow anyone else to publish to the web?

Back 3

Edit /etc/httpd/conf/httpd.conf

add
UserDir enabled sam

Front 4

Apache must be started with root privileges. Why? Why does this action not present a security risk?

Back 4

It must be in root because apache listens on port 80, which is a privileged port. It is not a threat because once apache has started using the port it releases the root privileges.

Front 5

Assume you want to provide Webmail access for employees on the same server that hosts the corporate website. The website address is example.com you want to use mail.example.com for the webmail and you want the webmail application located in the /var/www/webmail. Describe two ways to do this.

Back 5

1. You could use a virtual server of mail.example.com and have it files located in /var/www/webmail

2. Create a new server of mail.example.com and point it at /var/www/webmail with DocumentRoot

Front 6

Describe how you would prevent people outside the company's internal 192.168.0.0/16 network from accessing this site. Defined as.

<virtualHost *>
ServerName example.com
DocumentRoot /var/ww
<Directory /var/www/intranet>
AllowOverride AuthConfig
</Directory>
</VirtualHost>

Back 6

First you would add the following lines into the httpd.conf file.
<Directory /var/www/html/corp>
Order deny,allow
Deny from all
Allow from 192.168.
</Directory>

Then you would create a .htaccess file that looked like this:
Order deny, allow
Deny from all
Allow from 192.168.

Front 7

How would you remove all iptables rules and chains, but not change policy?

Back 7

Iptables --delete-chain

Front 8

How would you list all current iptables rules?

Back 8

Iptables --list

Front 9

How is configuring iptables different from configuring most linux services?

Back 9

Instead of having to use an editor to go into a file and add rules, you just use the Iptables command to add rules. Also you do not need to restart the Iptables service every time you add a rule.

Front 10

Define an iptables rule that will reject incoming connections on the TELNET port.

Back 10

iptables -A INPUT --append FORWARD --sport telnet -j REJECT

Front 11

What does NAT stand for? What does the NAT table do?

Back 11

Network Address Translation. A NAT tables rewrites the destination address of a packet. It translates one IP address into another.

Front 12

What does the conntrack module do?

Back 12

The conntrack module provides information on the state of a packet. This allows you to define rules that match criteria based on the state of the connection the packet is part of. This module handles connection tracking.

Front 13

What do rule match criteria do? What are they used for?

Back 13

Rule match criteria identify existing rules.

Front 14

What do packet match criteria do? What are they used for?

Back 14

Packet match criteria identify network packets and implement rules that take action on packets that match that criteria. It is used to identify which packets need to be filtered based on some rules. It implements rules that take action on packets that match a certain criteria.

Front 15

Which utilities copy packet filtering rules to and from the kernel? How do they work?

Back 15

The Iptables-save utility copies packet filtering rules to and from the kernel

Front 16

Write a rule that will silently block incoming SMTP connections from 10.10.10.10.

Back 16

Iptables –append FORWARD --dport smtp --source 10.10.10.10 –jump DROP

Front 17

Which are the two daemons of the samba suite? What does each do?

Back 17

The two daemons that are part of the samba suite are smbd and nmbd. Smbd provides file and print services, while nmbd provides browsing support and netBios name service.

Front 18

What steps are required for mapping a windows user to a different Linux user?

Back 18

In order to map a windows user to a Linux user you need to set the “username map” parameter in the smb.conf file to point to the map file. This file is usually located at /etc/samba/smbusers. Once you have done that you need to assign a Samba password to the user.

Front 19

How can a system administrator add a samba password for a user

Back 19

smbpasswd

Front 20

What is the purpose of the [home] share? Should this share be browsable? Why?

Back 20

The [homes] share shares the home directory of each user without having to define it specifically. It should be browseable only to the user and not to everyone. Only the user needs to access his/her home drive.

Front 21

Describe how samba's handling of users differs from that of NFS?

Back 21

With an NFS share they are mounted by root and NFS maps users on the client to users on the server. With Samba a share is mounted by a non-root user and all accesses to the share is under that users name.

Front 22

Which configuration changes would you need to apply to routers if they wanted to allow SMB/CIFS browsing across multiple subnets without configuring master browsers?

Back 22

Since routers don’t usually allow broadcast packets to travel between subnets and since browsing uses broadcast you would need to configure the router to forward the broadcast packets between the subnets.

Front 23

How could you use swat securely from a remote location?

Back 23

To provide the most secure connection you would want to use swat through SSL option. This encryption on the remote connection.

Front 24

WINS resolution allows hosts to define their own named. Suggest a way to use Samba to assign named from a centralized list.

Back 24

One way is to configure the Samba server to act like a WINS server. To do this you would enable a DNS proxy mode and keep the centralized list in DNS and configure each of the clients to use WINS. If the NetBios fails to resolve than the Samba server will use DNS to resolve the systems name.

Front 25

By default email's sent to a system goes to root. How would you also save a copy in /var/logs/systemmail?

Back 25

I would edit the /etc/aliases file and include “system: root, /var/logs/systemmail”

Front 26

How would Max store a copy of his email in ~/mbox and send a copy to [e-mail]?

Back 26

Create a forward file.
create sam/.forward and add
~/mbox
[e-mail]
\max

Front 27

If you firewall allows only the machine with the IP address 192.168.1.1 to send email outside the network, how would you instruct the local copy of sendmail to use this server as a relay?

Back 27

edit the /etc/mail/access and add the following
Connect 192.168.1.1 RELAY

Front 28

What does dnl stand for in the m4 macro language? what are dnl commands used for?

Back 28

Delete to new line, its used like a comment

Front 29

Describe the software and protocols used when Max sends an email to Sam on a remote Linux system?

Back 29

a. Max’s MUA sends the email to sendmail.
b. Then the sendmail uses SMTP to deliver the email to the sendmail on Sam’s system.
c. Then Sam’s sendmail sends the email to the MDA.
d. Then the MDA stores the email in the spool directory
e. Then Sam’s MDA grabs the email from the spool directory

Front 30

Give a simple way of reading your email that does not involve the use of an mua

Back 30

use the mail command or look in the /home/user/Maildir

Front 31

If you accidentally delete /etc/alisases file how could you easily re-create it?

Back 31

praliases > /etc/alsiases

Front 32

What does NFS stand for

Back 32

Network File System

Front 33

What does DNS stand for

Back 33

Domain Name Services