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Quick Reference Table, because John Gerth always found it useful. Original HTML. Like an old book of log tables, this is just a curiosity now, as there are better tools¹² available.

`255.255.255.128`	`FF.FF.FF.80`	`FF.FF.FF.1:0000000`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`126`	`valid`	`0`	`0`	`1-126`	`127`
`126`	`not valid`	`128`	`1`	`129-254`	`255`

`255.255.255.192`	`FF.FF.FF.C0`	`FF.FF.FF.11:000000`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`62`	`valid`	`0`	`00`	`1-62`	`63`
`62`	`valid`	`64`	`01`	`65-126`	`127`
`62`	`valid`	`128`	`10`	`129-190`	`191`
`62`	`not valid`	`192`	`11`	`193-254`	`255`

`255.255.255.224`	`FF.FF.FF.E0`	`FF.FF.FF.111:00000`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`30`	`valid`	`0`	`000`	`1-30`	`31`
`30`	`valid`	`32`	`001`	`33-62`	`63`
`30`	`valid`	`64`	`010`	`65-94`	`95`
`30`	`valid`	`96`	`011`	`97-126`	`127`
`30`	`valid`	`128`	`100`	`129-158`	`159`
`30`	`valid`	`160`	`010`	`161-190`	`191`
`30`	`valid`	`192`	`110`	`193-222`	`223`
`30`	`not valid`	`224`	`111`	`225-254`	`255`

`255.255.255.240`	`FF.FF.FF.F0`	`FF.FF.FF.1111:0000`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`14`	`valid`	`0`	`0000`	`1-14`	`15`
`14`	`valid`	`16`	`0001`	`17-30`	`31`
`14`	`valid`	`32`	`0010`	`33-46`	`47`
`14`	`valid`	`48`	`0011`	`49-62`	`63`
`14`	`valid`	`64`	`0100`	`65-78`	`79`
`14`	`valid`	`80`	`0101`	`81-94`	`95`
`14`	`valid`	`96`	`0110`	`97-110`	`111`
`14`	`valid`	`112`	`0111`	`113-126`	`127`
`14`	`valid`	`128`	`1000`	`129-142`	`143`
`14`	`valid`	`144`	`1001`	`145-158`	`159`
`14`	`valid`	`160`	`1010`	`161-174`	`175`
`14`	`valid`	`176`	`1011`	`178-190`	`191`
`14`	`valid`	`192`	`1100`	`193-206`	`207`
`14`	`valid`	`208`	`1101`	`209-222`	`223`
`14`	`valid`	`224`	`1110`	`225-238`	`239`
`14`	`not valid`	`240`	`1111`	`241-254`	`255`

`255.255.255.248`	`FF.FF.FF.F8`	`FF.FF.FF.11111:000`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`6`	`valid`	`0`	`00000`	`1-6`	`7`
`6`	`valid`	`8`	`00001`	`9-14`	`15`
`6`	`valid`	`16`	`00010`	`17-22`	`23`
`6`	`valid`	`24`	`00011`	`24-30`	`31`
`6`	`valid`	`32`	`00100`	`33-38`	`39`
`6`	`valid`	`40`	`00101`	`41-46`	`47`
`6`	`valid`	`48`	`00110`	`49-54`	`55`
`6`	`valid`	`56`	`00111`	`57-62`	`36`
`6`	`valid`	`64`	`01000`	`65-70`	`71`
`6`	`valid`	`72`	`01001`	`73-78`	`79`
`6`	`valid`	`80`	`01010`	`81-86`	`87`
`6`	`valid`	`88`	`01011`	`89-94`	`95`
`6`	`valid`	`96`	`01100`	`97-106`	`107`
`6`	`valid`	`108`	`01101`	`109-110`	`111`
`6`	`valid`	`112`	`01110`	`113-118`	`119`
`6`	`valid`	`120`	`01111`	`121-126`	`127`
`6`	`valid`	`128`	`10000`	`129-134`	`135`
`6`	`valid`	`136`	`10001`	`137-142`	`143`
`6`	`valid`	`144`	`10010`	`145-150`	`151`
`6`	`valid`	`152`	`10011`	`153-158`	`159`
`6`	`valid`	`160`	`10100`	`161-166`	`167`
`6`	`valid`	`168`	`10101`	`196-174`	`175`
`6`	`valid`	`176`	`10110`	`177-182`	`183`
`6`	`valid`	`184`	`10111`	`185-190`	`191`
`6`	`valid`	`192`	`11000`	`193-198`	`199`
`6`	`valid`	`200`	`11001`	`201-206`	`207`
`6`	`valid`	`208`	`11010`	`209-214`	`215`
`6`	`valid`	`216`	`11011`	`217-222`	`223`
`6`	`valid`	`224`	`11100`	`225-230`	`231`
`6`	`valid`	`232`	`11101`	`233-238`	`239`
`6`	`valid`	`240`	`11110`	`241-246`	`247`
`6`	`not valid`	`248`	`11111`	`249-254`	`255`

`255.255.255.252`	`FF.FF.FF.FC`	`FF.FF.FF.111111:00`

nodes per network	valid networks	network address	bit set	address range	broadcast address
`2`	`valid`	`0`	`000000`	`1-2`	`3`
`2`	`valid`	`4`	`000001`	`5-6`	`7`
`2`	`valid`	`8`	`000010`	`9-10`	`11`
`2`	`valid`	`12`	`000011`	`13-14`	`15`
`2`	`valid`	`16`	`000100`	`17-18`	`19`
`2`	`valid`	`20`	`000101`	`21-22`	`23`
`2`	`valid`	`24`	`000110`	`25-26`	`27`
`2`	`valid`	`28`	`000111`	`29-30`	`31`
`2`	`valid`	`32`	`001000`	`33-34`	`35`
`2`	`valid`	`36`	`001001`	`37-38`	`39`
`2`	`valid`	`40`	`001010`	`41-42`	`43`
`2`	`valid`	`44`	`001011`	`45-46`	`47`
`2`	`valid`	`48`	`001100`	`49-50`	`51`
`2`	`valid`	`52`	`001101`	`53-54`	`55`
`2`	`valid`	`56`	`001110`	`57-58`	`59`
`2`	`valid`	`60`	`001111`	`61-62`	`63`
`2`	`valid`	`64`	`010000`	`65-66`	`67`
`2`	`valid`	`68`	`010001`	`69-70`	`71`
`2`	`valid`	`72`	`010010`	`73-74`	`75`
`2`	`valid`	`76`	`010011`	`77-78`	`79`
`2`	`valid`	`80`	`010100`	`81-82`	`83`
`2`	`valid`	`84`	`010101`	`58-86`	`87`
`2`	`valid`	`88`	`010110`	`89-90`	`91`
`2`	`valid`	`92`	`010111`	`93-94`	`95`
`2`	`valid`	`96`	`011000`	`97-98`	`99`
`2`	`valid`	`100`	`011001`	`101-102`	`103`
`2`	`valid`	`104`	`011010`	`105-106`	`107`
`2`	`valid`	`108`	`011011`	`109-110`	`111`
`2`	`valid`	`112`	`011100`	`113-114`	`115`
`2`	`valid`	`116`	`011101`	`117-118`	`119`
`2`	`valid`	`120`	`011110`	`121-122`	`123`
`2`	`valid`	`124`	`011111`	`125-126`	`127`
`2`	`valid`	`128`	`100000`	`129-130`	`131`
`2`	`valid`	`132`	`100001`	`133-134`	`135`
`2`	`valid`	`136`	`100010`	`137-138`	`139`
`2`	`valid`	`140`	`100011`	`141-142`	`143`
`2`	`valid`	`144`	`100100`	`145-146`	`147`
`2`	`valid`	`148`	`100101`	`149-150`	`151`
`2`	`valid`	`152`	`100110`	`153-154`	`155`
`2`	`valid`	`156`	`100111`	`157-158`	`159`
`2`	`valid`	`160`	`101000`	`161-162`	`163`
`2`	`valid`	`164`	`101001`	`165-166`	`167`
`2`	`valid`	`168`	`101010`	`169-170`	`171`
`2`	`valid`	`172`	`101011`	`173-174`	`175`
`2`	`valid`	`176`	`101100`	`177-178`	`179`
`2`	`valid`	`180`	`101101`	`181-182`	`183`
`2`	`valid`	`184`	`101110`	`185-186`	`187`
`2`	`valid`	`188`	`101111`	`189-190`	`191`
`2`	`valid`	`192`	`110000`	`193-194`	`195`
`2`	`valid`	`196`	`110001`	`197-198`	`199`
`2`	`valid`	`200`	`110010`	`201-202`	`203`
`2`	`valid`	`204`	`110011`	`205-206`	`207`
`2`	`valid`	`208`	`110100`	`209-210`	`211`
`2`	`valid`	`212`	`110101`	`213-214`	`215`
`2`	`valid`	`216`	`110110`	`217-218`	`219`
`2`	`valid`	`220`	`110111`	`221-222`	`223`
`2`	`valid`	`224`	`111000`	`225-226`	`227`
`2`	`valid`	`228`	`111001`	`229-230`	`231`
`2`	`valid`	`232`	`111010`	`233-234`	`235`
`2`	`valid`	`236`	`111011`	`237-238`	`239`
`2`	`valid`	`240`	`111100`	`241-242`	`243`
`2`	`valid`	`244`	`111101`	`245-246`	`247`
`2`	`valid`	`248`	`111110`	`249-250`	`251`
`2`	`not valid`	`252`	`111111`	`253-254`	`255`

at⋅a⋅rax⋅is

Class C IP Addresses (192-223).x.x.x

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