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Thread ID: 41470 2004-01-12 07:55:00 IP Range Suffixes cyberchuck (173) Press F1
Post ID Timestamp Content User
206935 2004-01-12 07:55:00 Righto, well while I've been voyaging the net doing this and that I've noticed that some sites are listing IP Addresses with a suffix at the end such as:
127.0.0.1/8
129.223.96.0/19
129.223.123.0/24

I've looked through google except not knowing exactly what they are (and me being me) I haven't found anything useful, so (in laymans terms please) what are they, what purpose do they serve/what do they do and what do they mean?

Thanks



CyberChuck
cyberchuck (173)
206936 2004-01-12 08:25:00 I have always understood this to be:

127.0.0.1/8 means the range of:-

127.0.0.1, 127.0.0.2, 127.0.0.3, 127.0.0.4, 127.0.0.5, 127.0.0.6, 127.0.0.7, 127.0.0.8

??
godfather (25)
206937 2004-01-12 18:08:00 Thanks for that - it's what I thought too...
Just wanted some clarification as Murphy's law says I would've thought that left it alone and then when someone asks me I give them the wrong info :p
cyberchuck (173)
206938 2004-01-12 20:02:00 That's what I thought too godfather until I starting getting into networking a bit more. Then I found out that it is called 'slash notation' and here's an explanation:

192.168.1.0/24
192.168.1.23/32
195.153.161.128/25

To the left of the "slash" character (/) is the IP address or network address being referred to. To the right of the "slash" character is a number that specifies the number of significant "bits" in the address.

IP addresses are 32 bit numbers consisting of four eight bit numbers separated by periods (.). Therefore, the number following the slash character must be between 1 and 32.

Here are some examples of common slash-notated addresses, with their meanings:-

192.168.14.12/32 - Refers to the single computer with the IP address "192.168.14.12". The /32 tells us that all 32 bits of the address are relevant.

192.168.14.0/24 - Refers to a group of computers with addresses ranging from 192.168.14.0 to 192.168.14.255. The /24 tells us that the first 24 bits (i.e. the first three numbers in the dotted quad) are relevant.

192.168.17.128/25 - Refers to a group of computers with addresses ranging from 192.168.17.128 to 192.168.17.255. The /25 tells us that the first 25 bits of the address are relevant.
CYaBro (73)
206939 2004-01-12 20:04:00 Here's (www.sysdom.org) a page with a list of all 32 prefixes and what they mean as a subnet mask CYaBro (73)
206940 2004-01-13 03:13:00 That's what is called subnetting It's how the "IP4" system is still working, by allowing allocation of addresses in groups smaller than those defined by the A, B, C groups. That was fine for the early years. It will not be needed when (if?) the IP6 addressing (with 128 bits) takes over. Graham L (2)
206941 2004-01-13 07:46:00 My Network Qualification (or study for it) tells me thats the number consecutive numbers in a Ip sized address making up the subnet mask...

EG.. 192.168.0.1 /24
= 11111111.11111111.11111111.00000000 (ignore dots, the are merely there for understanding)
= 255.255.255.0

OR

=192.168.0.1 /13
=11111111.11111000.00000000.00000000
=255.248.0.0

lol - but these are strange defintions, please correct me if my sources are wrong :D
Growly (6)
206942 2004-01-13 19:24:00 That's basically what I said Growly :) so I say you are correct!

If you have a look on the link I posted you'll see that /13 = 255.248.0.0
CYaBro (73)
206943 2004-01-13 21:33:00 Sorry, didn't mean to reiterate, just meant to reconfirm :D Growly (6)
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