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cit 330 exam 3
cit 330 exam 3 review
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Computer Networking
Undergraduate 1
12/12/2011

Additional Computer Networking Flashcards

 


 

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Term
ifconfig
Definition
lets you configure your interface
Term
if status
Definition
shows the status of network interfaces
Term
ifup and ifdown
Definition
command to toggle interfaces on or off
Term
route
Definition
lets you see routing table or create static routes
Term
ip
Definition
to replace ifconfig, but not very popular
Term
netcat
Definition
swiss army knife does a lot but poorly. Bad web browser, port scanner, used for simple file transfer.
Term
netstat
Definition
alone shows all connections to your machine, if netstat -r shows routing tambe, netstat -l shows info about your network adapter interface.
Term
tcpdump
Definition
runs in shell, protocol analyzer sniffer"text based monitors network and reports every packet thati sees. Like Wireshark.
Term
ethereal
Definition
similar to TCPdump: diagnosis tool that lets you analyze data packets through a network interface. Like Wireshark.
Term

zone file record type

SOA

Definition
Start of authority: defines the domain
Term

Zone file record types

NS

Definition
Name server: Name of one of the DNS servers for this domain.
Term
MX
Definition
Mail exchanger: name and priority of a mail server for this domain.
Term
A
Definition
Address: ip address of a computer.
Term
PTR
Definition
Pointer: Name of a computer.
Term
CNAME
Definition
Canonical Name: alias name for a computer.
Term
zone file
Definition
Holds the address and hostname information within that domain.
Term
zone transfer
Definition
the way to zone file is distributed to the other servers. Uses a serial number at the top of the zone file, and Name servers compare it to decide when to update.
Term
resolv.conf
Definition
shows who your names servers are, also adds the search path ".byui.edu" search path appended. addresses for names servers and search path.
Term
nsswitch.conf
Definition
you tell Linux where it should go to resolve names, if it says [ files dns ] then it will go to local host file first, then to DNS, order matters.
Term
host
Definition
test your name servers replaced nslookup.
Term
dig
Definition
test your name servers, replaced nslookup (it does not append the search path)
Term
nslookup
Definition
test your name servers older less powerful one.
Term
NFS
Definition
if used to Linux to Linux machines, allows you to mount a remote file system into any directory tree.
Term
/etc/exports
Definition
where you create permanent export directories used by NFS. export is like sharing on the network.
Term
mount
Definition
cna mount from fstab/home/marko and mount it.
Term
fuser
Definition
lets you find out which usres have a file open.
Term
samba
Definition
Linux to windows machines.
Term
CIFS
Definition
common internet file system: lets netbios run on top of tcpip.
Term
SMB
Definition
Server message block: portocol that lets linux communicate with windows like mapping network drives [NetBIOS//server/share]
Term
testparm
Definition
does a syntax check on /etc/samba/smb.conf
Term
nmblookup
Definition
displays registered names of a host.
Term
smbclient
Definition
lets you connect linux client to the windows server.
Term
smbstatus
Definition
lists currently existing connections to the samba server.
Term
CUPS
Definition
http://localhost:631[[[PORT 631]]]: Print server.
Term
PPD
Definition
Postscript printer definition, postscript = open standard for printing files.
Term

printing commands

lpadmin

Definition
create printers from the cmd prompt
Term

printing commands

lpoptions

Definition
to change properties of a printer
Term

printing commands

lpr

Definition
to print something lp will print also
Term

printing commands

lpq

Definition
or lp stat view the print queue
Term

printing commands

lprm

Definition
remove a job or use [cancel]
Term
NIS
Definition
Network information services, do domain wide authentication services, replicated critical files only works on Linux and Unix. Originally called Yellow Pages (YP)
Term
LDAP
Definition
NIS but works on everything, compatible with windows active directory.
Term

LDAP record types

cn

Definition
canonical name: user name printer file or directory. (lowest level name)
Term

LDAP record types

ou

Definition
organizational unit: group users together into an organization (enginerring, IT, finance)
Term

LDAP record types

dc

Definition
domain component: where you specify your domain, all orgs belong to BYUI --- requires two components dc=ybyui, dc=edu.
Term
MIME
Definition
Multi purpose Mail extension: way we can determine the type of a file, what kind of data and what should we use to open it. In windows we use an extension like .exe .txt. I node Mime flag to tell the OS what type it is.
Term
SMTP
Definition
Simple mail transfer protocol: used to send mail, not to receive mail.
Term
MTA
Definition
Mail transfer agent, used to send the mail to its destination or destination server uses IMAP and POP.
Term
MDA
Definition
Mail delivery agent, compare the mail to a number of rules, and decide what to with it. so filters, Postfix and Sendmail.
Term
MUA
Definition
Mail user agent: your mail client. examples: Novell Evolution, KMail, Mozilla Thunderbird, Mutt(not gui), Pine (no gui), mail(no gui).
Term
POP and IMAP
Definition
once mail gets to the server it si distributed to the client with these.
Term
Postfix
Definition
MDA newer easier to config and manage compadable with sendmail.
Term
Sendmail
Definition
MDA old an reliable and difficult to manage.
Term
Procmail
Definition
setup file in /home/.procmailrc to configure soring options.
Term
inetd
Definition
super daemon: starts other daemons when they are needed.
Term
xinetd
Definition
new and improved version of inetd.
Term
TCP wrapper
Definition
adds security to other less secure daemons, telnet daemon is insecure, so instead of rewriting, use tcp wrapper which wraps itself around it adding more security, uses host.allow and host.deny statements.
Term
hosts.allow
Definition
tcp wrapper ACLS 1
Term
host.deny
Definition
tcp wrapper ACLS 2
Term
ssh
Definition
Secure shell remote connections logins, that you can copy files using scp tunneling of other protocols within it (open tunnel between two hosts you can run less secure protocols) -x allows x server to run across this server.
Term
dhcp
Definition
Dynamic Host Configuration Protocol: assigns a client a network/host address. Uses /etc.dhcpcd.conf and etc/sysconfig/dhcpcp.
Term
apache2
Definition
web server; home page is in /srv/www/htdocs. to start [rcapache2start] and stop [rcapache2stop].
Term
resident set
Definition
which pages are currently in physical memory.
Term
working set size
Definition
number of pages in current memory.
Term
thrashing
Definition
when you spend all time moving pages between physical and virtual memory and don't have any time to get real work done just moving everything.
Term
principle of locality
Definition
program and data references within a process tend to cluster. (even though I have a process that is this long, how much do i really need right now)
Term
paging
Definition
take process and divide into fixed xize pages and divide memory into frames.
Term
p bit
Definition
physical bit, 0 (in physical memory) 1 (in virtual memory)
Term
m bit
Definition
modified bit, to know if we need to write something before you reuse the frame. if both aren't unmodified then replace the LRU file (least recently used)
Term
critical section
Definition
section fo the program that we need to protect with a semaphore, lock at beginning and unlock at the end. Instead just isolate the critical code.
Term
livelock
Definition
you have two processes concurrently and their contending with each other over some resoure, ex: create a boolean and set it true and other program sets it false, each changes truth value.
Term
race condition
Definition
if two processe are running at the same time running concurrently I get different results thatn if they were running separately.
Term
semaphore
Definition
lock resources to a process to prevent deadlock, or any problems (check example with resources and queue) semwait and semsignal codes.
Term

conditions for deadlock

mutual exclusion

Definition
only one process can do it at a time (printing, updating files)
Term

conditions for deadlock

hold-and-wait

 

Definition
if a process gets a resource it can hold it until it gets the one it needs.
Term

conditions for deadlock

no preemption

Definition
resource cannot be removed from a process.
Term
circular wait
Definition

means you have a deadlock

 

Term
[image]
Definition

circles: processes

squares: resources

dots: how many instances of that resource  exist.

arrow from process: request for the resource.

arrow from resource: resouce is held by that process.

make sure to watch directions fo arrows and number of dots. One extra dot can prevent a deadlock.

Term
bash scripting
Definition
how to write scripts, remember the whole shebang #!/bin/bash and in perl it is #!/usr/bin/perl.
Term
parameters
Definition
parameters get sored in $1 $2
Term
read
Definition
[read -p var]
Term

<

 

Definition

lexicographical, compares the first character

if put inside a (()) then it interprets it as numberical.

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