Networking/Subneting


 * source --> http://www.subnetonline.com/pages/references/ipv4-cheat-sheet.php

IPV4 CHEAT SHEET

CIDR SUBNET MASK CHEATSHEET, ICMP TYPE CODES & EXTREME NUMBERS

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

To delegate rDNS cidr blocks see: http://www.rfc-editor.org/rfc/rfc2317.txt

~ Note: Some allocations may be outdated 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                    ) ~

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  ) (rfc search:  http://www.rfc-editor.org/rfcsearch.html   ) (             http://www.ietf.org/ietf/1id-abstracts.txt )

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

--

well known ports: (rfc1700.txt) http://www.iana.org/assignments/port-numbers

protocol numbers: http://www.iana.org/assignments/protocol-numbers http://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]

Extreme Number Cheatsheet (for those having to deal with such quantities)

Le Système International d'Unités (SI) Decimal system Prefix's                      Factor                       Exponent  Prefix  Symbol

1 000 000 000 000 000 000 000 000 000 000 000 000  10^36 ..(undefined)  U*     1 000 000 000 000 000 000 000 000 000 000 000   10^33 .... vendeka* V*         1 000 000 000 000 000 000 000 000 000 000   10^30 ....... weka* W*             1 000 000 000 000 000 000 000 000 000   10^27 ...... xenna* X*                 1 000 000 000 000 000 000 000 000   10^24 ...... yotta  Y                     1 000 000 000 000 000 000 000   10^21 ...... zetta  Z                         1 000 000 000 000 000 000   10^18 ........ exa  E                             1 000 000 000 000 000   10^15 ....... peta  P                                 1 000 000 000 000   10^12 ....... tera  T                                     1 000 000 000   10^9 ........ giga  G                                         1 000 000   10^6 ........ mega  M                                             1 000   10^3 ........ kilo  k                                               100   10^2 ....... hecto  h                                                10   10^1 ........ deka  da                                               0.1   10^-1 ....... deci  d                                              0.01   10^-2 ...... centi  c                                             0.001   10^-3 ...... milli  m                                         0.000 001   10^-6 ...... micro  µ 0.000 000 001  10^-9 ....... nano   n                                 0.000 000 000 001   10^-12 ...... pico  p                             0.000 000 000 000 001   10^-15 ..... femto  f                         0.000 000 000 000 000 001   10^-18 ...... atto  a                     0.000 000 000 000 000 000 001   10^-21 ..... zepto  z                 0.000 000 000 000 000 000 000 001   10^-24 ..... yocto  y             0.000 000 000 000 000 000 000 000 001   10^-27 ..... xenno* x*         0.000 000 000 000 000 000 000 000 000 001   10^-30 ...... weko* w*     0.000 000 000 000 000 000 000 000 000 000 001   10^-33 ... vendeko* v* 0.000 000 000 000 000 000 000 000 000 000 000 001   10^-36 .(undefined)  u*

[... 000 000 000 000 000 000 000 000 000 000 ...] 10^100 .... googol* [... 000 000 000 000 000 000 000 000 000 000 ...] 10^googol. googolplex* google = 10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

(unofficial*)

note: The term "googol" was made up by a nephew of American mathematician Edward Kasner when Kasner asked him to create a name for a very large number

CERT® Coordination Center Intruder Detection Checklist http://web.archive.org/web/20080109214340/http://www.cert.org/tech_tips/intruder_detection_checklist.html

Convert Fahrenheit <> Celsius: Celsius = (Fahrenheit - 32) / 1.8 Fahrenheit = (Celsius * 1.8) + 32

One therm = 100,000 BTU = 29.29 Kw/hr = 29290 Watts

last updated: 19Jan2010 next update: 2011 original published (c)1990,(c)1991 P.E.G. Laboratories original drafted 1985 by T.E. @ the NASA Telemetry Groundstation, Moffett Field, CA original web publishing 08dec1992 P.E.G. Laboratories http://peglabs.com OK to reproduce in entirety only