Netmask Netmask (binary) CIDR Notes
_____________________________________________________________________________
255.255.255.255 11111111.11111111.11111111.11111111 /32 Host (single addr)
255.255.255.254 11111111.11111111.11111111.11111110 /31 Unuseable
255.255.255.252 11111111.11111111.11111111.11111100 /30 2 useable
255.255.255.248 11111111.11111111.11111111.11111000 /29 6 useable
255.255.255.240 11111111.11111111.11111111.11110000 /28 14 useable
255.255.255.224 11111111.11111111.11111111.11100000 /27 30 useable
255.255.255.192 11111111.11111111.11111111.11000000 /26 62 useable
255.255.255.128 11111111.11111111.11111111.10000000 /25 126 useable
255.255.255.0 11111111.11111111.11111111.00000000 /24 "Class C" 254 useable
255.255.254.0 11111111.11111111.11111110.00000000 /23 2 Class C's
255.255.252.0 11111111.11111111.11111100.00000000 /22 4 Class C's
255.255.248.0 11111111.11111111.11111000.00000000 /21 8 Class C's
255.255.240.0 11111111.11111111.11110000.00000000 /20 16 Class C's
255.255.224.0 11111111.11111111.11100000.00000000 /19 32 Class C's
255.255.192.0 11111111.11111111.11000000.00000000 /18 64 Class C's
255.255.128.0 11111111.11111111.10000000.00000000 /17 128 Class C's
255.255.0.0 11111111.11111111.00000000.00000000 /16 "Class B"
255.254.0.0 11111111.11111110.00000000.00000000 /15 2 Class B's
255.252.0.0 11111111.11111100.00000000.00000000 /14 4 Class B's
255.248.0.0 11111111.11111000.00000000.00000000 /13 8 Class B's
255.240.0.0 11111111.11110000.00000000.00000000 /12 16 Class B's
255.224.0.0 11111111.11100000.00000000.00000000 /11 32 Class B's
255.192.0.0 11111111.11000000.00000000.00000000 /10 64 Class B's
255.128.0.0 11111111.10000000.00000000.00000000 /9 128 Class B's
255.0.0.0 11111111.00000000.00000000.00000000 /8 "Class A"
254.0.0.0 11111110.00000000.00000000.00000000 /7
252.0.0.0 11111100.00000000.00000000.00000000 /6
248.0.0.0 11111000.00000000.00000000.00000000 /5
240.0.0.0 11110000.00000000.00000000.00000000 /4
224.0.0.0 11100000.00000000.00000000.00000000 /3
192.0.0.0 11000000.00000000.00000000.00000000 /2
128.0.0.0 10000000.00000000.00000000.00000000 /1
0.0.0.0 00000000.00000000.00000000.00000000 /0 IP space
Net Host Total
Net Addr Addr Addr Number
Class Range NetMask Bits Bits of hosts
----------------------------------------------------------
A 0-127 255.0.0.0 8 24 16777216 (i.e. 114.0.0.0)
B 128-191 255.255.0.0 16 16 65536 (i.e. 150.0.0.0)
C 192-254 255.255.255.0 24 8 256 (i.e. 199.0.0.0)
D 224-239 (multicast)
E 240-255 (reserved)
F 208-215 255.255.255.240 28 4 16
G 216/8 ARIN - North America
G 217/8 RIPE NCC - Europe
G 218-219/8 APNIC
H 220-221 255.255.255.248 29 3 8 (reserved)
K 222-223 255.255.255.254 31 1 2 (reserved)
(ref: RFC1375 & http://www.iana.org/assignments/ipv4-address-space )
( http://www.iana.org/numbers.htm )
----------------------------------------------------------
The current list of special use prefixes:
0.0.0.0/8
127.0.0.0/8
192.0.2.0/24
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
169.254.0.0/16
all D/E space
(ref: RFC1918 http://www.rfc-editor.org/rfc/rfc1918.txt )
( or ftp://ftp.isi.edu/in-notes/rfc1918.txt )
(rfc search: http://www.rfc-editor.org/rfcsearch.html )
( http://www.ietf.org/ietf/1id-abstracts.txt )
( http://www.ietf.org/shadow.html )
Martians: (updates at: www.iana.org/assignments/ipv4-address-space )
no ip source-route
access-list 100 deny ip host 0.0.0.0 any
deny ip 0.0.0.0 0.255.255.255 any log ! antispoof
deny ip 0.0.0.0 0.255.255.255 0.0.0.0 255.255.255.255 ! antispoof
deny ip any 255.255.255.128 0.0.0.127 ! antispoof
deny ip host 0.0.0.0 any log ! antispoof
deny ip host [router intf] [router intf] ! antispoof
deny ip xxx.xxx.xxx.0 0.0.0.255 any log ! lan area
deny ip 0/8 0.255.255.255 any log ! IANA - Reserved
deny ip 1/8 0.255.255.255 any log ! IANA - Reserved
deny ip 2/8 0.255.255.255 any log ! IANA - Reserved
deny ip 5/8 0.255.255.255 any log ! IANA - Reserved
deny ip 7/8 0.255.255.255 any log ! IANA - Reserved
deny ip 10.0.0.0 0.255.255.255 any log ! IANA - Private Use
deny ip 23/8 0.255.255.255 any log ! IANA - Reserved
deny ip 27/8 0.255.255.255 any log ! IANA - Reserved
deny ip 31/8 0.255.255.255 any log ! IANA - Reserved
deny ip 36-37/8 0.255.255.255 any log ! IANA - Reserved
deny ip 39/8 0.255.255.255 any log ! IANA - Reserved
deny ip 41-42/8 0.255.255.255 any log ! IANA - Reserved
deny ip 50/8 0.255.255.255 any log ! IANA - Reserved
deny ip 58-60/8 0.255.255.255 any log ! IANA - Reserved
deny ip 69-79/8 0.255.255.255 any log ! IANA - Reserved
deny ip 82-95/8 0.255.255.255 any log ! IANA - Reserved
deny ip 96-126/8 0.255.255.255 any log ! IANA - Reserved
deny ip 127/8 0.255.255.255 any log ! IANA - Reserved
deny ip 169.254.0.0 0.0.255.255 any log ! link-local network
deny ip 172.16.0.0 0.15.255.255 any log ! reserved
deny ip 192.168.0.0 0.0.255.255 any log ! reserved
deny ip 192.0.2.0 0.0.0.255 any log ! test network
deny ip 197/8 0.255.255.255 any log ! IANA - Reserved
deny ip 220/8 0.255.255.255 any log ! IANA - Reserved
deny ip 222-223/8 0.255.255.255 any log ! IANA - Reserved
deny ip 224.0.0.0 31.255.255.255 any log ! multicast
deny ip 224.0.0.0 15.255.255.255 any log ! unless MBGP-learned routes
deny ip 224-239/8 0.255.255.255 any log ! IANA - Multicast
deny ip 240-255/8 0.255.255.255 any log ! IANA - Reserved
filtered source addresses
0/8 ! broadcast
10/8 ! RFC 1918 private
127/8 ! loopback
169.254.0/16 ! link local
172.16.0.0/12 ! RFC 1918 private
192.0.2.0/24 ! TEST-NET
192.168.0/16 ! RFC 1918 private
224.0.0.0/4 ! class D multicast
240.0.0.0/5 ! class E reserved
248.0.0.0/5 ! reserved
255.255.255.255/32 ! broadcast
ARIN administrated blocks: (http://www.arin.net/regserv/IPStats.html)
24.0.0.0/8 (portions of)
63.0.0.0/8
64.0.0.0/8
65.0.0.0/8
66.0.0.0/8
196.0.0.0/8
198.0.0.0/8
199.0.0.0/8
200.0.0.0/8
204.0.0.0/8
205.0.0.0/8
206.0.0.0/8
207.0.0.0/8
208.0.0.0/8
209.0.0.0/8
216.0.0.0/8
----------------------------------------------------------
well known ports: (rfc1700.txt)
www.iana.org/assignments/port-numbers
protocol numbers:
www.iana.org/assignments/protocol-numbers
www.iana.org/numbers.htm
ICMP(Types/Codes)
Testing Destination Reachability & Status
(0/0) Echo-Reply
(8/0) Echo
Unreachable Destinations
(3/0) Network Unreachable
(3/1) Host Unreachable
(3/2) Protocol Unreachable
(3/3) Port Unreachable
(3/4) Fragmentaion Needed and DF set (Pkt too big)
(3/5) Source Route Failed
(3/6) Network Unknown
(3/7) Host Unknown
(3/9) DOD Net Prohibited
(3/10) DOD Host Prohibited
(3/11) Net TOS Unreachable
(3/12) Host TOS Unreachable
(3/13) Administratively Prohibited
(3/14) Host Precedence Unreachable
(3/15) Precedence Unreachable
Flow Control
(4/0) Source-Quench [RFC 1016]
Route Change Requests from Gateways
(5/0) Redirect Datagrams for the Net
(5/1) Redirect Datagrams for the Host
(5/2) Redirect Datagrams for the TOS and Net
(5/3) Redirect Datagrams for the TOS and Host
Router
(6/-) Alternate-Address
(9/0) Router-Advertisement
(10/0) Router-Solicitation
Detecting Circular or Excessively Long Routes
(11/0) Time to Live Count Exceeded
(11/1) Fragment Reassembly Time Exceeded
Reporting Incorrect Datagram Headers
(12/0) Parameter-Problem
(12/1) Option Missing
(12/2) No Room for Option
Clock Synchronization and Transit Time Estimation
(13/0) Timestamp-Request
(14/0) Timestamp-Reply
Obtaining a Network Address (RARP Alternative)
(15/0) Information-Request
(16/0) Information-Reply
Obtaining a Subnet Mask [RFC 950]
(17/0) Address Mask-Request
(18/0) Address Mask-Reply
Other
(30/0) Traceroute
(31/0) Conversion-Error
(32/0) Mobile-Redirect
Ref: [RFC 792] [RFC 896] [RFC 950] [RFC 1016]
www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_5_3/cofigide/qos.htm#19774
Decimal system Prefix's
Factor Exponent Prefix
---------------------------------------------------
1 000 000 000 000 000 000 000 000...10^24....yotta
1 000 000 000 000 000 000 000...10^21....zetta
1 000 000 000 000 000 000...10^18....exa
1 000 000 000 000 000...10^15....peta
1 000 000 000 000...10^12....tera
1 000 000 000...10^9.....giga
1 000 000...10^6.....mega
1 000...10^3.....kilo
100...10^2.....hecto
10...10^1.....deka
0.1...10^-1....deci
0.01...10^-2....centi
0.001...10^-3....milli
0.000 001...10^-6....micro
0.000 000 001...10^-9....nano
0.000 000 000 001...10^-12...pico
0.000 000 000 000 001...10^-15...femto
0.000 000 000 000 000 001...10^-18...atto
0.000 000 000 000 000 000 001...10^-21...zepto
0.000 000 000 000 000 000 000 001...10^-24...yocto
---------------------------------------------------
Convert Fahrenheit <> Celsius:
Celsius = (Fahrenheit - 32) / 1.8
Fahrenheit = (Celsius * 1.8) + 32
a
* alias Create an alias
* apropos Search Help manual pages (man -k)
* apt-get Search for and install software packages (Debian)
* aspell Spell Checker
* awk Find and Replace text, database sort/validate/index
b
* bash GNU Bourne-Again SHell
* bc Arbitrary precision calculator language
* bg Send to background
* break Exit from a loop
* builtin Run a shell builtin
* bzip2 Compress or decompress named file(s)
c
* cal Display a calendar
* case Conditionally perform a command
* cat Display the contents of a file
* cd Change Directory
* cfdisk Partition table manipulator for Linux
* chgrp Change group ownership
* chmod Change access permissions
* chown Change file owner and group
* chroot Run a command with a different root directory
* chkconfig System services (runlevel)
* cksum Print CRC checksum and byte counts
* clear Clear terminal screen
* cmp Compare two files
* comm Compare two sorted files line by line
* command Run a command – ignoring shell functions
* continue Resume the next iteration of a loop
* cp Copy one or more files to another location
* cron Daemon to execute scheduled commands
* crontab Schedule a command to run at a later time
* csplit Split a file into context-determined pieces
* cut Divide a file into several parts
d
* date Display or change the date & time
* dc Desk Calculator
* dd Convert and copy a file, write disk headers, boot records
* ddrescue Data recovery tool
* declare Declare variables and give them attributes
* df Display free disk space
* diff Display the differences between two files
* diff3 Show differences among three files
* dig DNS lookup
* dir Briefly list directory contents
* dircolors Colour setup for `ls’
* dirname Convert a full pathname to just a path
* dirs Display list of remembered directories
* dmesg Print kernel & driver messages
* du Estimate file space usage
e
* echo Display message on screen
* egrep Search file(s) for lines that match an extended expression
* eject Eject removable media
* enable Enable and disable builtin shell commands
* env Environment variables
* ethtool Ethernet card settings
* eval Evaluate several commands/arguments
* exec Execute a command
* exit Exit the shell
* expect Automate arbitrary applications accessed over a terminal
* expand Convert tabs to spaces
* export Set an environment variable
* expr Evaluate expressions
f
* false Do nothing, unsuccessfully
* fdformat Low-level format a floppy disk
* fdisk Partition table manipulator for Linux
* fg Send job to foreground
* fgrep Search file(s) for lines that match a fixed string
* file Determine file type
* find Search for files that meet a desired criteria
* fmt Reformat paragraph text
* fold Wrap text to fit a specified width.
* for Expand words, and execute commands
* format Format disks or tapes
* free Display memory usage
* fsck File system consistency check and repair
* ftp File Transfer Protocol
* function Define Function Macros
* fuser Identify/kill the process that is accessing a file
g
* gawk Find and Replace text within file(s)
* getopts Parse positional parameters
* grep Search file(s) for lines that match a given pattern
* groups Print group names a user is in
* gzip Compress or decompress named file(s)
h
* hash Remember the full pathname of a name argument
* head Output the first part of file(s)
* history Command History
* hostname Print or set system name
i
* id Print user and group id’s
* if Conditionally perform a command
* ifconfig Configure a network interface
* ifdown Stop a network interface
* ifup Start a network interface up
* import Capture an X server screen and save the image to file
* install Copy files and set attributes
j
* join Join lines on a common field
k
* kill Stop a process from running
* killall Kill processes by name
l
* less Display output one screen at a time
* let Perform arithmetic on shell variables
* ln Make links between files
* local Create variables
* locate Find files
* logname Print current login name
* logout Exit a login shell
* look Display lines beginning with a given string
* lpc Line printer control program
* lpr Off line print
* lprint Print a file
* lprintd Abort a print job
* lprintq List the print queue
* lprm Remove jobs from the print queue
* ls List information about file(s)
* lsof List open files
* make Recompile a group of programs
* man Help manual
* mkdir Create new folder(s)
* mkfifo Make FIFOs (named pipes)
* mkisofs Create an hybrid ISO9660/JOLIET/HFS filesystem
* mknod Make block or character special files
* more Display output one screen at a time
* mount Mount a file system
* mtools Manipulate MS-DOS files
* mv Move or rename files or directories
* mmv Mass Move and rename (files)
n
* netstat Networking information
* nice Set the priority of a command or job
* nl Number lines and write files
* nohup Run a command immune to hangups
* nslookup Query Internet name servers interactively
o
* open Open a file in its default application
* op Operator access
p
* passwd Modify a user password
* paste Merge lines of files
* pathchk Check file name portability
* ping Test a network connection
* pkill Stop processes from running
* popd Restore the previous value of the current directory
* pr Prepare files for printing
* printcap Printer capability database
* printenv Print environment variables
* printf Format and print data
* ps Process status
* pushd Save and then change the current directory
* pwd Print Working Directory
q
* quota Display disk usage and limits
* quotacheck Scan a file system for disk usage
* quotactl Set disk quotas
r
* ram ram disk device
* rcp Copy files between two machines
* read read a line from standard input
* readonly Mark variables/functions as readonly
* reboot Reboot the system
* renice Alter priority of running processes
* remsync Synchronize remote files via email
* return Exit a shell function
* rev Reverse lines of a file
* rm Remove files
* rmdir Remove folder(s)
* rsync Remote file copy (Synchronize file trees)
s
* screen Multiplex terminal, run remote shells via ssh
* scp Secure copy (remote file copy)
* sdiff Merge two files interactively
* sed Stream Editor
* select Accept keyboard input
* seq Print numeric sequences
* set Manipulate shell variables and functions
* sftp Secure File Transfer Program
* shift Shift positional parameters
* shopt Shell Options
* shutdown Shutdown or restart linux
* sleep Delay for a specified time
* slocate Find files
* sort Sort text files
* source Run commands from a file `.’
* split Split a file into fixed-size pieces
* ssh Secure Shell client (remote login program)
* strace Trace system calls and signals
* su Substitute user identity
* sudo Execute a command as another user
* sum Print a checksum for a file
* symlink Make a new name for a file
* sync Synchronize data on disk with memory
t
* tail Output the last part of files
* tar Tape ARchiver
* tee Redirect output to multiple files
* test Evaluate a conditional expression
* time Measure Program running time
* times User and system times
* touch Change file timestamps
* top List processes running on the system
* traceroute Trace Route to Host
* trap Run a command when a signal is set(bourne)
* tr Translate, squeeze, and/or delete characters
* true Do nothing, successfully
* tsort Topological sort
* tty Print filename of terminal on stdin
* type Describe a command
u
* ulimit Limit user resources
* umask Users file creation mask
* umount Unmount a device
* unalias Remove an alias
* uname Print system information
* unexpand Convert spaces to tabs
* uniq Uniquify files
* units Convert units from one scale to another
* unset Remove variable or function names
* unshar Unpack shell archive scripts
* until Execute commands (until error)
* useradd Create new user account
* usermod Modify user account
* users List users currently logged in
* uuencode Encode a binary file
* uudecode Decode a file created by uuencode
v
* v Verbosely list directory contents (`ls -l -b’)
* vdir Verbosely list directory contents (`ls -l -b’)
* vi Text Editor
* vmstat Report virtual memory statistics
w
* watch Execute/display a program periodically
* wc Print byte, word, and line counts
* whereis Report all known instances of a command
* which Locate a program file in the user’s path.
* while Execute commands
* who Print all usernames currently logged in
* whoami Print the current user id and name (`id -un’)
* Wget Retrieve web pages or files via HTTP, HTTPS or FTP
* write Send a message to another user
x
* xargs Execute utility, passing constructed argument list(s)
* yes Print a string until interrupted
* . Run a command script in the current shell
* ### Comment / Remark
xcopy C:*.* /s/c/d/e/h/i/r/k/y Z:*.*
Number of
Addresses Number of Bits Prefix Classful Notation Mask
1 0 /32 255.255.255.255
2 1 /31 255.255.255.254
4 2 /30 255.255.255.252
8 3 /29 255.255.255.248
16 4 /28 255.255.255.240
32 5 /27 255.255.255.224
64 6 /26 255.255.255.192
128 7 /25 255.255.255.128
256 8 /24 1 C 255.255.255
512 9 /23 2 C 255.255.254
1 K 10 /22 4 C 255.255.252
2 K 11 /21 8 C 255.255.248
4 K 12 /20 16 C 255.255.240
8 K 13 /19 32 C 255.255.224
16 K 14 /18 64 C 255.255.192
32 K 15 /17 128 C 255.255.128
64 K 16 /16 1 B 255.255
128 K 17 /15 2 B 255.254
256 K 18 /14 4 B 255.252
512 K 19 /13 8 B 255.248
1 M 20 /12 16 B 255.240
2 M 21 /11 32 B 255.224
4 M 22 /10 64 B 255.192
8 M 23 /9 128 B 255.128
16 M 24 /8 1 A 255
32 M 25 /7 2 A 254
64 M 26 /6 4 A 252
128 M 27 /5 8 A 248
256 M 28 /4 16 A 240
512 M 29 /3 32 A 224
1024 M 30 /2 64 A 192