ip range question....10.0.0.0/32 etc...

Tom Nielsen

20 Jan 2004 20 Jan '04

23:28

How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/? Thanks, Tom -- Tom Nielsen Neuro Logic Systems 805.389.5435 x18 www.neuro-logic.com

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Jeffrey L. Taylor

20 Jan 20 Jan

23:34

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Quoting Tom Nielsen :

...

How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/?

192.168.0.0/24 i.e., 24 most significant bits identify the network, 8 least significant bits identify hosts on the network. HTH, Jeffrey

George Auch

23:35

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tuesday 20 January 2004 6:28 pm, Tom Nielsen wrote:

...

How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/?

Thanks, Tom

Tom, 192.168.0.0/24 192.168.1.0 -> 192.168.0.255 try a search on google for 'whatmask', a small program that is usefull in working with subnets. George -- Linux 2.6.1 #1 Fri Jan 16 09:28:12 EST 2004 i686 6:32pm up 1 day 3:22, 5 users, load average: 0.03, 0.09, 0.08

Tom Nielsen

21 Jan 21 Jan

00:00

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Thanks. I knew it was something easy. Now what does 192..168.0.0/8 and 192.168.0.0/32 mean? I thought one was an absolute number. Tom On Tue, 2004-01-20 at 15:35, George Auch wrote:

...

On Tuesday 20 January 2004 6:28 pm, Tom Nielsen wrote:

...
How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/?

Thanks, Tom

Tom,

192.168.0.0/24 192.168.1.0 -> 192.168.0.255

try a search on google for 'whatmask', a small program that is usefull in working with subnets.

George

-- Linux 2.6.1 #1 Fri Jan 16 09:28:12 EST 2004 i686 6:32pm up 1 day 3:22, 5 users, load average: 0.03, 0.09, 0.08

-- Tom Nielsen Neuro Logic Systems 805.389.5435 x18 www.neuro-logic.com

Ken Schneider

00:11

New subject: [SLE] ip range question....10.0.0.0/32 etc...

-----Original Message----- From: Tom Nielsen To: Suse Date: Tue, 20 Jan 2004 16:00:37 -0800 Subject: Re: [SLE] ip range question....10.0.0.0/32 etc...

...

Thanks. I knew it was something easy.

Now what does 192..168.0.0/8 and 192.168.0.0/32 mean? I thought one was an absolute number.

Tom

192.168.0.0/8 = 255.0.0.0 so won't work. 192.0.0.0/8 will. You are trying to use class A subnetting on a class B network address. 192.168.0.0/32 = 255.255.255.255 won't work, 192.168.0.1/32 will. You are trying to lock down to a single address and and a 0 and the last position specifies a network not a host. As I remember my early training. Ken Schneider

Tom Nielsen

00:19

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tue, 2004-01-20 at 16:11, Ken Schneider wrote:

...

-----Original Message----- From: Tom Nielsen To: Suse Date: Tue, 20 Jan 2004 16:00:37 -0800 Subject: Re: [SLE] ip range question....10.0.0.0/32 etc...

...
Thanks. I knew it was something easy.

Now what does 192..168.0.0/8 and 192.168.0.0/32 mean? I thought one was an absolute number.

Tom

192.168.0.0/8 = 255.0.0.0 so won't work. 192.0.0.0/8 will. You are trying to use class A subnetting on a class B network address.

192.168.0.0/32 = 255.255.255.255 won't work, 192.168.0.1/32 will. You are trying to lock down to a single address and and a 0 and the last position specifies a network not a host.

As I remember my early training.

Ken Schneider

Oh, my aching head!!!!! Tom -- Tom Nielsen Neuro Logic Systems 805.389.5435 x18 www.neuro-logic.com

Graham Smith

03:14

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Tom, As someone previously mentioned have a look at whatmask. The source can be found here http://www.laffeycomputer.com/whatmask.html An online demo can be found here http://grox.net/utils/whatmask/ ------------------------------------------------ TCP/IP NETWORK INFORMATION ------------------------------------------------ IP Entered = ..................: 192.168.1.0 CIDR = ........................: /24 Netmask = .....................: 255.255.255.0 Wildcard Bits = ...............: 0.0.0.255 ------------------------------------------------ Network Address = .............: 192.168.1.0 Broadcast Address = ...........: 192.168.1.255 Usable IP Addresses = .........: 254 First Usable IP Address = .....: 192.168.1.1 Last Usable IP Address = ......: 192.168.1.254 -- Regards, Graham Smith ---------------------------------------------------------

LW999

20 Mar 20 Mar

10:31

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Graham Smith wrote:

...

Tom,

As someone previously mentioned have a look at whatmask.

The source can be found here http://www.laffeycomputer.com/whatmask.html

An online demo can be found here http://grox.net/utils/whatmask/

------------------------------------------------ TCP/IP NETWORK INFORMATION ------------------------------------------------ IP Entered = ..................: 192.168.1.0 CIDR = ........................: /24 Netmask = .....................: 255.255.255.0 Wildcard Bits = ...............: 0.0.0.255 ------------------------------------------------ Network Address = .............: 192.168.1.0 Broadcast Address = ...........: 192.168.1.255 Usable IP Addresses = .........: 254 First Usable IP Address = .....: 192.168.1.1 Last Usable IP Address = ......: 192.168.1.254

James Knott

21 Jan 21 Jan

01:34

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Ken Schneider wrote:

...

-----Original Message----- From: Tom Nielsen To: Suse Date: Tue, 20 Jan 2004 16:00:37 -0800 Subject: Re: [SLE] ip range question....10.0.0.0/32 etc...

...
Thanks. I knew it was something easy.

Now what does 192..168.0.0/8 and 192.168.0.0/32 mean? I thought one was an absolute number.

Tom

192.168.0.0/8 = 255.0.0.0 so won't work. 192.0.0.0/8 will. You are trying to use class A subnetting on a class B network address.

192.168.0.0/32 = 255.255.255.255 won't work, 192.168.0.1/32 will. You are trying to lock down to a single address and and a 0 and the last position specifies a network not a host.

As I remember my early training.

Actually, as I recall it, the /32 would be used on a point to point link, where there is only one address.

Scot L. Harris

02:00

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tue, 2004-01-20 at 20:34, James Knott wrote:

...

Actually, as I recall it, the /32 would be used on a point to point link, where there is only one address.

On a point to point link you would use 30 bit subnets. A 30 bit subnet has a subnet mask of 255.255.255.252. This defines two host addresses that can be used on the point to point network as well as the broadcast address and the subnet. -- Scot L. Harris

James Knott

03:01

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Scot L. Harris wrote:

...

On Tue, 2004-01-20 at 20:34, James Knott wrote:

...
Actually, as I recall it, the /32 would be used on a point to point link, where there is only one address.

On a point to point link you would use 30 bit subnets. A 30 bit subnet has a subnet mask of 255.255.255.252. This defines two host addresses that can be used on the point to point network as well as the broadcast address and the subnet.

Are you sure about that? There's only the 2 addresses, as there's no need for a broadcast or network address. In fact, I just checked on my notebook. Ifconfig shows a mask of 255.255.255.255 for ppp0, an inet address, a P-t-P address and no broadcast address. Eth0 shows an inet address, broadcast address and a mask of 255.255.255.0. Maybe you'd better check your facts again. Fire up a ppp link and tell me what you see.

Scot L. Harris

04:16

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tue, 2004-01-20 at 22:01, James Knott wrote:

...

Scot L. Harris wrote:

...
On Tue, 2004-01-20 at 20:34, James Knott wrote:

...
Actually, as I recall it, the /32 would be used on a point to point link, where there is only one address.

On a point to point link you would use 30 bit subnets. A 30 bit subnet has a subnet mask of 255.255.255.252. This defines two host addresses that can be used on the point to point network as well as the broadcast address and the subnet.

Are you sure about that? There's only the 2 addresses, as there's no need for a broadcast or network address.

In fact, I just checked on my notebook. Ifconfig shows a mask of 255.255.255.255 for ppp0, an inet address, a P-t-P address and no broadcast address. Eth0 shows an inet address, broadcast address and a mask of 255.255.255.0.

Maybe you'd better check your facts again. Fire up a ppp link and tell me what you see.

Think about it. A point to point link needs two addresses in the subnet. 192.168.0.0/32 gives you: subnet address of 192.168.0.0 broadcast address of 192.168.0.3 host 1 address of 192.168.0.1 host 2 address of 192.168.0.2 Have setup hundreds of these on frame relay circuits and private line circuits. We may be talking two different things here. The point to point protocol I believe uses a 32 bit subnet to say the entire address can be assigned. -- Scot L. Harris

Jim Cunning

04:45

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Today at 11:16pm, Scot L. Harris wrote:

...

On Tue, 2004-01-20 at 22:01, James Knott wrote: [snip]

...
Are you sure about that? There's only the 2 addresses, as there's no need for a broadcast or network address.

In fact, I just checked on my notebook. Ifconfig shows a mask of 255.255.255.255 for ppp0, an inet address, a P-t-P address and no broadcast address. Eth0 shows an inet address, broadcast address and a mask of 255.255.255.0.

Maybe you'd better check your facts again. Fire up a ppp link and tell me what you see.

Think about it. A point to point link needs two addresses in the subnet.

192.168.0.0/32 gives you:

I think you wanted to say "192.168.0.0/30" here.

...

subnet address of 192.168.0.0 broadcast address of 192.168.0.3 host 1 address of 192.168.0.1 host 2 address of 192.168.0.2

Have setup hundreds of these on frame relay circuits and private line circuits.

We may be talking two different things here. The point to point protocol I believe uses a 32 bit subnet to say the entire address can be assigned.

There is no requirement on a point-to-point link that both ends be in the same subnet. For that matter, there is no requirement that either the near or far interface have an IP address at all. Anything the local host sends to the near end interface is only going to go to the far end interface--at which point further routing must happen. Cisco has been doing that for years, even on frame relay circuits. Jim

Scot L. Harris

04:53

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tue, 2004-01-20 at 23:45, Jim Cunning wrote:

...

There is no requirement on a point-to-point link that both ends be in the same subnet. For that matter, there is no requirement that either the near or far interface have an IP address at all. Anything the local host sends to the near end interface is only going to go to the far end interface--at which point further routing must happen. Cisco has been doing that for years, even on frame relay circuits.

Jim

Yes, circuitless connections. Nortel routers also support that. Never used those much as it made monitoring and trouble shooting of the circuits more difficult. There are several ways to skin a cat and to setup a network. ;) -- Scot L. Harris

Kenneth Schneider

12:33

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tue, 2004-01-20 at 23:53, Scot L. Harris wrote:

...

On Tue, 2004-01-20 at 23:45, Jim Cunning wrote:

...
There is no requirement on a point-to-point link that both ends be in the same subnet. For that matter, there is no requirement that either the near or far interface have an IP address at all. Anything the local host sends to the near end interface is only going to go to the far end interface--at which point further routing must happen. Cisco has been doing that for years, even on frame relay circuits.

Jim

Yes, circuitless connections. Nortel routers also support that. Never used those much as it made monitoring and trouble shooting of the circuits more difficult. There are several ways to skin a cat and to setup a network. ;)

Even though we are getting OT here, have you ever had a eth interface on a router go down but the circuit was still up? Try connecting (telnet) to the router without an IP on the serial interface. I do this quite often to help trouble shoot a connection problem. -- Ken Schneider unix user since 1989 linux user since 1994 SuSE user since 1998 (5.2)

scsijon

24 Jan 24 Jan

02:29

New subject: [SLE] ip range question....10.0.0.0/32 etc...

At 11:53 PM 20/01/2004, Scot L. Harris wrote:

...

On Tue, 2004-01-20 at 23:45, Jim Cunning wrote:

...
There is no requirement on a point-to-point link that both ends be in the same subnet. For that matter, there is no requirement that either the near or far interface have an IP address at all. Anything the local host sends to the near end interface is only going to go to the far end interface--at which point further routing must happen. Cisco has been doing that for years, even on frame relay circuits.

Jim

Yes, circuitless connections. Nortel routers also support that. Never used those much as it made monitoring and trouble shooting of the circuits more difficult. There are several ways to skin a cat and to setup a network. ;) UM, have we hijacked the thread and are we now off topic folks?

We use to use the Mac addresses to chase through these links, it took a little longer typing them in but you ALWAYS knew you were dealing with the link in question. Cisco even has software to direct connect for this (no interface code required). regards scsijon

James Knott

22 Jan 22 Jan

00:20

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Scot L. Harris wrote:

...

On Tue, 2004-01-20 at 22:01, James Knott wrote:

...
Scot L. Harris wrote:

...
On Tue, 2004-01-20 at 20:34, James Knott wrote:

...
Actually, as I recall it, the /32 would be used on a point to point link, where there is only one address.

On a point to point link you would use 30 bit subnets. A 30 bit subnet has a subnet mask of 255.255.255.252. This defines two host addresses that can be used on the point to point network as well as the broadcast address and the subnet.

Are you sure about that? There's only the 2 addresses, as there's no need for a broadcast or network address.

In fact, I just checked on my notebook. Ifconfig shows a mask of 255.255.255.255 for ppp0, an inet address, a P-t-P address and no broadcast address. Eth0 shows an inet address, broadcast address and a mask of 255.255.255.0.

Maybe you'd better check your facts again. Fire up a ppp link and tell me what you see.

Think about it. A point to point link needs two addresses in the subnet.

192.168.0.0/32 gives you:

subnet address of 192.168.0.0 broadcast address of 192.168.0.3 host 1 address of 192.168.0.1 host 2 address of 192.168.0.2

Have setup hundreds of these on frame relay circuits and private line circuits.

We may be talking two different things here. The point to point protocol I believe uses a 32 bit subnet to say the entire address can be assigned.

This started when a question was posted about a 32 bit subnet mask. I said it was valid on point to point links and you (IIRC) said that it wasn't. I provided an example, by describing my ppp link. This one example is proof of what I said. Anything you've done becomes irrelevant, because it can't undo my proof that 255.255.255.255 is a valid subnet mask for a point to point link. Here's what ifconfig shows, when I use dial up ppp. ppp0 Link encap:Point-to-Point Protocol inet addr:209.188.82.150 P-t-P:209.188.80.74 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:6 errors:0 dropped:0 overruns:0 frame:0 TX packets:6 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:95 (95.0 b) TX bytes:101 (101.0 b) Did you notice the subnet mask? As for your connections, how are you setting up the connection? If using an ethernet card to talk to the CSU etc., you may still have to allow at least 4 addresses.

Paul W. Abrahams

21 Jan 21 Jan

02:53

New subject: [SLE] ip range question....10.0.0.0/32 etc...

I'm curious if there are any uses for netmasks with noncontiguous bits such as 255.255.255.1, or with rightmost bits set, such as 0.0.0.127. Paul Abrahams

James Knott

01:33

New subject: [SLE] ip range question....10.0.0.0/32 etc...

Tom Nielsen wrote:

...

Thanks. I knew it was something easy.

Now what does 192..168.0.0/8 and 192.168.0.0/32 mean? I thought one was an absolute number.

The 192.168.0.0/8 is not quite correct. The /8 implies only 8 network bits, so the correct address range would be 192.0.0.0/8.

George Auch

20 Jan 20 Jan

23:48

New subject: [SLE] ip range question....10.0.0.0/32 etc...

On Tuesday 20 January 2004 6:28 pm, Tom Nielsen wrote:

...

How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/?

Thanks, Tom

To be a little more specific: 192.168.0.0/24 192.168.0.0 is the Network Address /24 is the CIDR The first usable ip is 192.168.0.1 The last usable ip is 192.168.0.254 192.168.0.255 is the broadcast address HTH George -- Linux 2.6.1 #1 Fri Jan 16 09:28:12 EST 2004 i686 6:44pm up 1 day 3:33, 3 users, load average: 0.07, 0.10, 0.09

Ken Schneider

21 Jan 21 Jan

00:03

New subject: [SLE] ip range question....10.0.0.0/32 etc...

-----Original Message----- From: Tom Nielsen To: Suse Date: Tue, 20 Jan 2004 15:28:06 -0800 Subject: [SLE] ip range question....10.0.0.0/32 etc...

...

How do I list an ip so that covers the whole range of the last numbers? E.g 192.168.0.0 to 192.168.0.256 = 192.168.0.0/?

192.168.0.0/24 This represents 24 bits of the mask which = 255.255.255.0 Ken Schneider

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20 comments

12 participants

participants (12)

George Auch
Graham Smith
James Knott
Jeffrey L. Taylor
Jim Cunning
Ken Schneider
Kenneth Schneider
LW999
Paul W. Abrahams
Scot L. Harris
scsijon
Tom Nielsen