ITI

Which statements apply to LANs?

Which statements apply when comparing connectionless and connection-oriented communication?

Which statements apply to point-to-point networks?

Select one or more:

The total size of a layer 3 PDU is 1956 bytes. This includes the size of the layer 3 header which is 20 bytes. Layer 2 can only handle payloads of 988 bytes. Therefore, layer 3 has to split the single PDU into a minimum number of smaller PDUs. Summing up the size of all resulting smaller PDUs, what is the total number of bytes? (Enter just a number without any additional text, e.g., 1234)

Which statements apply to WANs?

Which statements apply to the functionality of different layers in the OSI model?

Which protocols are Internet Layer protocols?

Host A receives data from host B. Currently, host A is so busy that it has to drop data received from host B due to missing processing capacity. Which common functionality of layers would be of help in that case?

Which statements apply to the peer-to-peer model of communication?

Which statements apply to the client-server model of communication?

Which protocols are connectionless?

What is the Solicited-Node multicast address that corresponds to the IPv6 address fe80::6cef:c9ff:fe09:b55a? (compress zeros within the address as much as possible)

Consider classful addressing. What is the class of the IP address 199.44.128.0?

What is the characteristic of IPv6 unicast addresses?

What is the characteristic of IPv6 anycast addresses?

What is the length of an IPv6 address?

What is the characteristic of IPv6 multicast addresses?

The MAC address of an interface is 12:84:94:31:84:82. What is the corresponding IPv6 Link-Local address with an interface id according to the modified EUI-64 format? (compress zeros within the address as much as possible)

What is the length of an IPv4 address?

Which of the following IPv6 addresses is a Unique Local addresses?

Which IPv6 address is assigned to the loopback interface? (compress zeros within the address as much as possible)

Which statements apply to the Domain Name System (DNS)?

Which special domain name is used to perform a DNS reverse lookup for the IP address 2001:db8:a359:3aaa::c8?

Which type of DNS resource record is used to specify the canonical name for an alias domain name (enter just the type identifier, e.g.: SOA)?

Which special domain name is used to perform a DNS reverse lookup for the IP address 196.252.255.164?

Which is the intended usage of the top-level domain: gov?

Certain file systems and swap areas should be mounted/activated at system start. Which config file(s) may be used for this?

For each user, what is stored in the file /etc/passwd?

Consider a Linux host with two network interfaces, eth0 which is connected to LAN0, and eth1 which is connected to LAN1. Principally, forwarding of IP packets has been enabled (for this, the value ”1” has to be written to the files /proc/sys/net/ipv4/ip_forward and/or /proc/sys/net/ipv6/conf/all/forwarding).

The netfilter framework has been configured such that the policies of all built-in chains in the filter table are set to DROP, and the following rules are added:

root@compu:~# iptables -A INPUT -i eth0 -j ACCEPT 
root@compu:~# iptables -A INPUT -i eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth1 -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT

Note, the option -i specifies the incoming interface and the option -ospecifies the outgoing interface

Consider the Linux host and some host on LAN0. Which host has to initiate the connection, so that they can communicate with each other?

Consider a Linux host with two network interfaces, eth0 which is connected to LAN0, and eth1 which is connected to LAN1. Principally, forwarding of IP packets has been enabled (for this, the value ”1” has to be written to the files /proc/sys/net/ipv4/ip_forward and/or /proc/sys/net/ipv6/conf/all/forwarding).

The netfilter framework has been configured such that the policies of all built-in chains in the filter table are set to DROP, and the following rules are added:

root@compu:~# iptables -A INPUT -i eth0 -j ACCEPT 
root@compu:~# iptables -A INPUT -i eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth1 -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT

Note, the option -i specifies the incoming interface and the option -ospecifies the outgoing interface.

Consider the Linux host and some host on LAN1. Which host has to initiate the connection, so that they can communicate with each other?

Consider a Linux host with two network interfaces, eth0 which is connected to LAN0, and eth1 which is connected to LAN1. Principally, forwarding of IP packets has been enabled (for this, the value ”1” has to be written to the files /proc/sys/net/ipv4/ip_forward and/or /proc/sys/net/ipv6/conf/all/forwarding).

The netfilter framework has been configured such that the policies of all built-in chains in the filter table are set to DROP, and the following rules are added:

root@compu:~# iptables -A INPUT -i eth0 -j ACCEPT 
root@compu:~# iptables -A INPUT -i eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth1 -j ACCEPT 
root@compu:~# iptables -A OUTPUT -o eth0 -m state --state ESTABLISHED,RELATED -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth1 -o eth0 -j ACCEPT 
root@compu:~# iptables -A FORWARD -i eth0 -o eth1 -m state --state ESTABLISHED,RELATED -j ACCEPT

Note, the option -i specifies the incoming interface and the option -ospecifies the outgoing interface

Consider a host on LAN0 and a host on LAN1. Which host has to initiate the connection, so that they can communicate with each other?

On a GNU/Linux system, you have just created a new user with the command adduser. Thereby, a new group has also been created. Now, you issue the following command:

root@compu:~# ls --sort=time /etc/?[^u]* | head -4

With the option --sort=time, the command ls lists the files sorted according to the modification time, where the most recently modified file comes first. Which of the following files will be shown in the output of the command above (considering that no other files have been modified since the user/group has been created).

Consider the following sequence of commands:

root@compu:~# id user88 
uid=3607(user88) gid=6280(group27) groups=6280(group27) 
root@compu:~# ls -l /tmp/file1 
-rw-r--r-- 1 user88 group27 0 Jan 01 10:45 /tmp/file1 
root@compu:~# deluser user88 
Removing user `user88' ... 
Warning: group `group27' has no more members. 
Done. 
root@compu:~# delgroup group27 
Removing group `group27' ... 
Done. 
root@compu:~# ls -l /tmp/file1

Note, the command deluser/delgroup removes the given user/group from the relevant config files in /etc/.

In the output of the last command, what is shown in the owner field?

Consider the following sequence of commands:

root@compu:~# id user88 
uid=3607(user88) gid=6280(group27) groups=6280(group27) 
root@compu:~# ls -l /tmp/file1 
-rw-r--r-- 1 user88 group27 0 Jan 01 10:45 /tmp/file1 
root@compu:~# deluser user88 
Removing user `user88' ... 
Warning: group `group27' has no more members. 
Done. 
root@compu:~# delgroup group27 
Removing group `group27' ... 
Done. 
root@compu:~# ls -l /tmp/file1

Note, the command deluser/delgroup removes the given user/group from the relevant config files in /etc/.

In the output of the last command, what is shown in the group field?

Which of the following commands are used to configure network interfaces under GNU/Linux?

Consider an LDAP Directory Information Tree that starts with an entry with the base DN: dc=example,dc=org Which of the following names could be DNs in this tree?

Consider the definition of the person object class in the LDAP schema:

objectclass ( 2.5.6.6 NAME 'person' 
      DESC 'RFC2256: a person' 
      SUP top STRUCTURAL 
      MUST ( sn $ cn ) 
      MAY ( userPassword $ telephoneNumber $ seeAlso $ description ) )

Is it possible to set up an entry with object class person and supplying the attributes "cn" and "description" only?

Consider the definition of the person object class in the LDAP schema:

objectclass ( 2.5.6.6 NAME 'person' 
      DESC 'RFC2256: a person' 
      SUP top STRUCTURAL 
      MUST ( sn $ cn ) 
      MAY ( userPassword $ telephoneNumber $ seeAlso $ description ) )

Is it possible to set up an entry with the only object class person and amongst others an attribute "mobile"?

The OpenLDAP Software 2.4 Administrator's Guide contains the following section about configuration choices: "Local Directory Service with Referrals" Given an LDAP client C and two LDAP servers A and B, so, what is supported by OpenLDAP?

Consider an LDAP Directory Information Tree that starts with an entry with the base DN: dc=example,dc=org Which of the following names could be RDNs in this tree?