Network Cheatsheet :: src: http://www.luckydragon.net/tech/network_cheatsheet.html ############################################################################### 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 For wildcard netmasks (aka reverse netmasks), subtract each octet of a standard netmask from 255. Example 1: 255.255.255.0 becomes 0.0.0.255 Example 2: 255.255.252.0 becomes 0.0.3.255 ############################################################################### 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 Protocol Protocol Number -------- --------------- ICMP 1 IGRP 9 EIGRP 88 OSPF 89 IPv6 41 GRE 47 IPX in IP 111 L2TP 115 ############################################################################### * ICMP Type Numbers Type Name Reference ---- ------------------------- --------- 0 Echo Reply [RFC792] Codes 0 No Code 1 Unassigned [JBP] 2 Unassigned [JBP] 3 Destination Unreachable [RFC792] Codes 0 Net Unreachable 1 Host Unreachable 2 Protocol Unreachable 3 Port Unreachable 4 Fragmentation Needed and Don't Fragment was Set 5 Source Route Failed 6 Destination Network Unknown 7 Destination Host Unknown 8 Source Host Isolated 9 Communication with Destination Network is Administratively Prohibited 10 Communication with Destination Host is Administratively Prohibited 11 Destination Network Unreachable for Type of Service 12 Destination Host Unreachable for Type of Service 13 Communication Administratively Prohibited [RFC1812] 14 Host Precedence Violation [RFC1812] 15 Precedence cutoff in effect [RFC1812] 4 Source Quench [RFC792] Codes 0 No Code 5 Redirect [RFC792] Codes 0 Redirect Datagram for the Network (or subnet) 1 Redirect Datagram for the Host 2 Redirect Datagram for the Type of Service and Network 3 Redirect Datagram for the Type of Service and Host 6 Alternate Host Address [JBP] Codes 0 Alternate Address for Host 7 Unassigned [JBP] 8 Echo [RFC792] Codes 0 No Code 9 Router Advertisement [RFC1256] Codes 0 Normal router advertisement 16 Does not route common traffic [RFC2002] 10 Router Selection [RFC1256] Codes 0 No Code 11 Time Exceeded [RFC792] Codes 0 Time to Live exceeded in Transit 1 Fragment Reassembly Time Exceeded 12 Parameter Problem [RFC792] Codes 0 Pointer indicates the error 1 Missing a Required Option [RFC1108] 2 Bad Length 13 Timestamp [RFC792] Codes 0 No Code 14 Timestamp Reply [RFC792] Codes 0 No Code 15 Information Request [RFC792] Codes 0 No Code 16 Information Reply [RFC792] Codes 0 No Code 17 Address Mask Request [RFC950] Codes 0 No Code 18 Address Mask Reply [RFC950] Codes 0 No Code 19 Reserved (for Security) [Solo] 20-29 Reserved (for Robustness Experiment) [ZSu] 30 Traceroute [RFC1393] 31 Datagram Conversion Error [RFC1475] 32 Mobile Host Redirect [David Johnson] 33 IPv6 Where-Are-You [Bill Simpson] 34 IPv6 I-Am-Here [Bill Simpson] 35 Mobile Registration Request [Bill Simpson] 36 Mobile Registration Reply [Bill Simpson] 39 SKIP [Markson] 40 Photuris [RFC2521] Codes 0 = Bad SPI 1 = Authentication Failed 2 = Decompression Failed 3 = Decryption Failed 4 = Need Authentication 5 = Need Authorization 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] ############################################################################### 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 ###############################################################################