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

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