{"id":3,"date":"2007-08-31T22:45:37","date_gmt":"2007-09-01T01:45:37","guid":{"rendered":"http:\/\/www.foxnet.com.br\/portal2\/?p=3"},"modified":"2008-04-29T22:49:59","modified_gmt":"2008-04-30T01:49:59","slug":"ip-subnet-mask-numbers","status":"publish","type":"post","link":"https:\/\/www.foxnet.com.br\/portal3\/?p=3","title":{"rendered":"IP-Subnet-Mask numbers"},"content":{"rendered":"

IP mask numbers are used to divide internet addresses into blocks called subnets. The mask number represents the number of 1s in the binary of the address that is ‘masked” against the address So that it ignores the last bits which as for the group of IP addresses in the masked address.<\/span>\u00a0<\/p>\n

The first address of a subnet block (all 0s) is called the network address or network<\/span> ID.\u00a0 The last address (all 1s) is the broadcast address of the network. Typically the network<\/span> address +1 or the broadcast address -1 is the gateway to the internet.\u00a0The ‘slash’ notation (ie \/24) is known as CIDR
\nformat, while the more conventional 255.255.255.0 notation is considered a subnet mask.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Net bits<\/th>\nSubnet mask<\/th>\ntotal-addresses<\/th>\n<\/tr>\n
\/20<\/td>\n255.255.240.0<\/td>\n4096<\/td>\n<\/tr>\n
\/21<\/td>\n255.255.248.0<\/td>\n2048<\/td>\n<\/tr>\n
\/22<\/td>\n255.255.252.0<\/td>\n1024<\/td>\n<\/tr>\n
\/23<\/td>\n255.255.254.0<\/td>\n512<\/td>\n<\/tr>\n
\/24<\/td>\n255.255.255.0<\/td>\n256<\/td>\n<\/tr>\n
\/25<\/td>\n255.255.255.128<\/td>\n128<\/td>\n<\/tr>\n
\/26<\/td>\n255.255.255.192<\/td>\n64<\/td>\n<\/tr>\n
\/27<\/td>\n255.255.255.224<\/td>\n32<\/td>\n<\/tr>\n
\/28<\/td>\n255.255.255.240<\/td>\n16<\/td>\n<\/tr>\n
\/29<\/td>\n255.255.255.248<\/td>\n8<\/td>\n<\/tr>\n
\/30<\/td>\n255.255.255.252<\/td>\n4<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The first address of a subnet block (all 0s) is called the network address or network ID.\u00a0 The last address (all 1s) is the broadcast address of the network. Typically the network address +1 or the broadcast address -1 is the gateway to the internet.\u00a0This leaves us with total number of IP numbers -3 left over for host address with in a sub net block. That’s why you either get 1 IP (4-3= 1) or if you ask for one more you get 5 (8-3=5).\u00a0<\/p>\n

Here is an example:<\/h3>\n

192.168.1.0\/25 would include all address between 192.168.1.0 and 192.168.1.127<\/p>\n

while 192.168.1.128\/25 would include\u00a0 192.168.1.128 and 192.168.1.255<\/p>\n

Below is a mask table that makes it easy to look up the mask for a group of IP addresses.<\/p>\n

Mask table<\/h3>\n

Mask = \/24<\/h4>\n

0-255<\/p>\n

Mask = \/25<\/h4>\n

0-127
\n128-255<\/p>\n

Mask = \/26<\/h4>\n
0-63\r\n64-127\r\n128-191\r\n192-255<\/pre>\n
Mask = \/27<\/h4>\n
0-31\r\n32-63\r\n64-95\r\n96-127\r\n128-159\r\n160-191\r\n192-223\r\n224-255<\/pre>\n
Mask = \/28<\/h4>\n
0-15\r\n16-31\r\n32-47\r\n48-63\r\n64-79\r\n80-95\r\n96-111\r\n112-127\r\n128-143\r\n144-159\r\n160-175\r\n176-191\r\n192-207\r\n208-223\r\n224-239\r\n240-255<\/pre>\n
Mask = \/29<\/h4>\n
0-7\r\n8-15\r\n16-23\r\n24-31\r\n32-39\r\n40-47\r\n48-55\r\n56-63\r\n64-71\r\n72-79\r\n80-87\r\n88-95\r\n96-103\r\n104-111\r\n112-119\r\n120-127\r\n128-135\r\n136-143\r\n144-151\r\n152-159\r\n160-167\r\n168-175\r\n176-183\r\n184-191\r\n192-199\r\n200-207\r\n208-215\r\n216-223\r\n224-231\r\n232-239\r\n240-247\r\n248-255<\/pre>\n
Mask = \/30<\/h4>\n
0-3\r\n4-7\r\n8-11\r\n12-15\r\n16-19\r\n20-23\r\n24-27\r\n28-31\r\n32-35\r\n36-39\r\n40-43\r\n44-47\r\n48-51\r\n52-55\r\n56-59\r\n60-63\r\n64-67\r\n68-71\r\n72-75\r\n76-79\r\n80-83\r\n84-87\r\n88-91\r\n92-95\r\n96-99\r\n100-103\r\n104-107\r\n108-111\r\n112-115\r\n116-119\r\n120-123\r\n124-127\r\n128-131\r\n132-135\r\n136-139\r\n140-143\r\n144-147\r\n148-151\r\n152-155\r\n156-159\r\n160-163\r\n164-167\r\n168-171\r\n172-175\r\n176-179\r\n180-183\r\n184-187\r\n188-191\r\n192-195\r\n196-199\r\n200-203\r\n204-207\r\n208-211\r\n212-215\r\n216-219\r\n220-223\r\n224-227\r\n228-231\r\n232-235\r\n236-239\r\n240-243\r\n244-247\r\n248-251\r\n252-255<\/pre>\n
Netmasks<\/h2>\n
Netmask              Netmask (binary)                 CIDR     Notes\r\n255.255.255.255  11111111.11111111.11111111.11111111  \/32  Host (single addr)\r\n255.255.255.254  11111111.11111111.11111111.11111110  \/31  Unuseable\r\n255.255.255.252  11111111.11111111.11111111.11111100  \/30    2  useable\r\n255.255.255.248  11111111.11111111.11111111.11111000  \/29    6  useable\r\n255.255.255.240  11111111.11111111.11111111.11110000  \/28   14  useable\r\n255.255.255.224  11111111.11111111.11111111.11100000  \/27   30  useable\r\n255.255.255.192  11111111.11111111.11111111.11000000  \/26   62  useable\r\n255.255.255.128  11111111.11111111.11111111.10000000  \/25  126  useable\r\n255.255.255.0    11111111.11111111.11111111.00000000  \/24 \"Class C\" 254 useable\r\n\r\n255.255.254.0    11111111.11111111.11111110.00000000  \/23    2  Class C's\r\n255.255.252.0    11111111.11111111.11111100.00000000  \/22    4  Class C's\r\n255.255.248.0    11111111.11111111.11111000.00000000  \/21    8  Class C's\r\n255.255.240.0    11111111.11111111.11110000.00000000  \/20   16  Class C's\r\n255.255.224.0    11111111.11111111.11100000.00000000  \/19   32  Class C's\r\n255.255.192.0    11111111.11111111.11000000.00000000  \/18   64  Class C's\r\n255.255.128.0    11111111.11111111.10000000.00000000  \/17  128  Class C's\r\n255.255.0.0      11111111.11111111.00000000.00000000  \/16  \"Class B\"\r\n\r\n255.254.0.0      11111111.11111110.00000000.00000000  \/15    2  Class B's\r\n255.252.0.0      11111111.11111100.00000000.00000000  \/14    4  Class B's\r\n255.248.0.0      11111111.11111000.00000000.00000000  \/13    8  Class B's\r\n255.240.0.0      11111111.11110000.00000000.00000000  \/12   16  Class B's\r\n255.224.0.0      11111111.11100000.00000000.00000000  \/11   32  Class B's\r\n255.192.0.0      11111111.11000000.00000000.00000000  \/10   64  Class B's\r\n255.128.0.0      11111111.10000000.00000000.00000000  \/9   128  Class B's\r\n255.0.0.0        11111111.00000000.00000000.00000000  \/8   \"Class A\"\r\n\r\n254.0.0.0        11111110.00000000.00000000.00000000  \/7\r\n252.0.0.0        11111100.00000000.00000000.00000000  \/6\r\n248.0.0.0        11111000.00000000.00000000.00000000  \/5\r\n240.0.0.0        11110000.00000000.00000000.00000000  \/4\r\n224.0.0.0        11100000.00000000.00000000.00000000  \/3\r\n192.0.0.0        11000000.00000000.00000000.00000000  \/2\r\n128.0.0.0        10000000.00000000.00000000.00000000  \/1\r\n0.0.0.0          00000000.00000000.00000000.00000000  \/0   IP space<\/pre>\n","protected":false},"excerpt":{"rendered":"
IP mask numbers are used to divide internet addresses into blocks called subnets. The mask number represents the number of 1s in the binary of the address that is ‘masked” against the address So that it ignores the last bits which as for the group of IP addresses in the masked address.\u00a0 The first address… <\/p>\n
Read More<\/i><\/a><\/div>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20,19],"tags":[37],"class_list":["post-3","post","type-post","status-publish","format-standard","hentry","category-redes_dicas","category-redes","tag-ip-subnet-netmask"],"_links":{"self":[{"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/posts\/3","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3"}],"version-history":[{"count":1,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/posts\/3\/revisions"}],"predecessor-version":[{"id":671,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=\/wp\/v2\/posts\/3\/revisions\/671"}],"wp:attachment":[{"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.foxnet.com.br\/portal3\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}