Confused about IP rules

Hi All,

I hope this is the correct newsgroup for this question.

I have come accross conflicting descriptions about some limitations
concerning IP adressing.

To make it short, I will directly jump into my confusion.

I have found out that the DHCP scope of my local network is set by someone
as 10.0.0.4 thru 10.0.0.99

In an article on the Internet, I have read that 10.0.0.x is not exactly a
legal adress, as well as 10.255.255.x

On the books that I read, I come accross some examples which give 10.0.0.4
and so on.

I understand that neither the network ID or the host ID cannot be 0 or 255.
I'm not sure if this means the ID as a full expression, or any single octet
in the ID.

What I want to know is, staying strictly with legal limits, can I use this
scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?

I will further appreciate pointers to a (THE) authoritative lecture-type
document freely available in the Internet (not the RFC's)

Thanks,
Engin

Okay, I'll try to explain

10.X.X.X is what's known as a private address range. They're considered
non-routable by the internet as a whole, and are used to create private
networks. The same goes for 192.168.X.X and 172.16.X.X

10.0.0.X (with a subnetmask of 255.255.255.0) is a perfectly legit address,
as long as X isn't 255 or 0. Those are reserved for the network and
broadcast addresses respectively.

You can have 0's and 255's in the network part of the IP setup, and you CAN
also have them in the host part as well, if you're dealing with a "strange"
IP range.

Try giving this a read: http://www.ipprimer.com/addressing.cfm

And if you still have questions after that, come back, and we'll try and get
em answered.

Matt Gibson - GSEC


"oldguy" <(E-Mail Removed)> wrote in message
news:ukSPK%(E-Mail Removed)...
> Hi All,
>
> I hope this is the correct newsgroup for this question.
>
> I have come accross conflicting descriptions about some limitations
> concerning IP adressing.
>
> To make it short, I will directly jump into my confusion.
>
> I have found out that the DHCP scope of my local network is set by someone
> as 10.0.0.4 thru 10.0.0.99
>
> In an article on the Internet, I have read that 10.0.0.x is not exactly a
> legal adress, as well as 10.255.255.x
>
> On the books that I read, I come accross some examples which give 10.0.0.4
> and so on.
>
> I understand that neither the network ID or the host ID cannot be 0 or
> 255. I'm not sure if this means the ID as a full expression, or any single
> octet in the ID.
>
> What I want to know is, staying strictly with legal limits, can I use this
> scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?
>
> I will further appreciate pointers to a (THE) authoritative lecture-type
> document freely available in the Internet (not the RFC's)
>
> Thanks,
> Engin
>
>

Many thanks Matt, particularly for the pointer.

As a last check, I would say that as long as I'm not messing around with
Internet and I keep myself confined to my little local "cage", I am allowed
to do anything (well, almost) that I want, as far as the IP addressing is
concerned. Is this correct?

Regards,
Engin



"Matt Gibson" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Okay, I'll try to explain
>
> 10.X.X.X is what's known as a private address range. They're considered
> non-routable by the internet as a whole, and are used to create private
> networks. The same goes for 192.168.X.X and 172.16.X.X
>
> 10.0.0.X (with a subnetmask of 255.255.255.0) is a perfectly legit
> address, as long as X isn't 255 or 0. Those are reserved for the network
> and broadcast addresses respectively.
>
> You can have 0's and 255's in the network part of the IP setup, and you
> CAN also have them in the host part as well, if you're dealing with a
> "strange" IP range.
>
> Try giving this a read: http://www.ipprimer.com/addressing.cfm
>
> And if you still have questions after that, come back, and we'll try and
> get em answered.
>
> Matt Gibson - GSEC
>
>
> "oldguy" <(E-Mail Removed)> wrote in message
> news:ukSPK%(E-Mail Removed)...
>> Hi All,
>>
>> I hope this is the correct newsgroup for this question.
>>
>> I have come accross conflicting descriptions about some limitations
>> concerning IP adressing.
>>
>> To make it short, I will directly jump into my confusion.
>>
>> I have found out that the DHCP scope of my local network is set by
>> someone as 10.0.0.4 thru 10.0.0.99
>>
>> In an article on the Internet, I have read that 10.0.0.x is not exactly a
>> legal adress, as well as 10.255.255.x
>>
>> On the books that I read, I come accross some examples which give
>> 10.0.0.4 and so on.
>>
>> I understand that neither the network ID or the host ID cannot be 0 or
>> 255. I'm not sure if this means the ID as a full expression, or any
>> single octet in the ID.
>>
>> What I want to know is, staying strictly with legal limits, can I use
>> this scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?
>>
>> I will further appreciate pointers to a (THE) authoritative lecture-type
>> document freely available in the Internet (not the RFC's)
>>
>> Thanks,
>> Engin
>>
>>
>
>

Yes, that is essentially correct. If you use the 10.0.0.x addresses it
won't even matter if you do somehow connect to the Internet. These addresses
are reserved for private use and will be ignored on the Internet. By that I
mean that the Internet routers are programmed to drop any packets with these
addresses.

oldguy wrote:
> Many thanks Matt, particularly for the pointer.
>
> As a last check, I would say that as long as I'm not messing around
> with Internet and I keep myself confined to my little local "cage", I
> am allowed to do anything (well, almost) that I want, as far as the
> IP addressing is concerned. Is this correct?
>
> Regards,
> Engin
>
>
>
> "Matt Gibson" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Okay, I'll try to explain
>>
>> 10.X.X.X is what's known as a private address range. They're
>> considered non-routable by the internet as a whole, and are used to
>> create private networks. The same goes for 192.168.X.X and
>> 172.16.X.X 10.0.0.X (with a subnetmask of 255.255.255.0) is a perfectly
>> legit
>> address, as long as X isn't 255 or 0. Those are reserved for the
>> network and broadcast addresses respectively.
>>
>> You can have 0's and 255's in the network part of the IP setup, and
>> you CAN also have them in the host part as well, if you're dealing
>> with a "strange" IP range.
>>
>> Try giving this a read: http://www.ipprimer.com/addressing.cfm
>>
>> And if you still have questions after that, come back, and we'll try
>> and get em answered.
>>
>> Matt Gibson - GSEC
>>
>>
>> "oldguy" <(E-Mail Removed)> wrote in message
>> news:ukSPK%(E-Mail Removed)...
>>> Hi All,
>>>
>>> I hope this is the correct newsgroup for this question.
>>>
>>> I have come accross conflicting descriptions about some limitations
>>> concerning IP adressing.
>>>
>>> To make it short, I will directly jump into my confusion.
>>>
>>> I have found out that the DHCP scope of my local network is set by
>>> someone as 10.0.0.4 thru 10.0.0.99
>>>
>>> In an article on the Internet, I have read that 10.0.0.x is not
>>> exactly a legal adress, as well as 10.255.255.x
>>>
>>> On the books that I read, I come accross some examples which give
>>> 10.0.0.4 and so on.
>>>
>>> I understand that neither the network ID or the host ID cannot be 0
>>> or 255. I'm not sure if this means the ID as a full expression, or
>>> any single octet in the ID.
>>>
>>> What I want to know is, staying strictly with legal limits, can I
>>> use this scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?
>>>
>>> I will further appreciate pointers to a (THE) authoritative
>>> lecture-type document freely available in the Internet (not the
>>> RFC's) Thanks,
>>> Engin

Additional to the other good comments,...I would recommend you use the
Scopes differently,...just as a good practice. Have the Scope use the
entire IP# as it is specified by the Mask. For example a 24 bit mask
(255.255.255.0) would give you the range of 10.0.0.0 - 10.0.0.255. After
you drop off the Net ID and the Broadcast address you will get 10.0.0.1 -
10.0.0.254.

So you create the Scope with the full Range and then use Exclusions to trim
it down to what you wan the DHCP Server to pass out to other machines.
Address within the Exclusions would be used for statically addressed
machines and other netwok devices.

Eaxmple of a Scope

IP Range: 10.0.0.1 -- 10.0.0.254
Exclusion #1: 10.0.0.1 -- 10.0.0.25
Exclusion #2: 10.0.0.200 -- 10.0.0.254
This gives a leasable range of 10.0.0.26 -- 10.0.0.199

You can also include WINS, Default Gateway (Router), and DNS Settings out to
machines with the Scope.


--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com


"oldguy" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Many thanks Matt, particularly for the pointer.
>
> As a last check, I would say that as long as I'm not messing around with
> Internet and I keep myself confined to my little local "cage", I am
allowed
> to do anything (well, almost) that I want, as far as the IP addressing is
> concerned. Is this correct?
>
> Regards,
> Engin
>
>
>
> "Matt Gibson" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Okay, I'll try to explain
> >
> > 10.X.X.X is what's known as a private address range. They're considered
> > non-routable by the internet as a whole, and are used to create private
> > networks. The same goes for 192.168.X.X and 172.16.X.X
> >
> > 10.0.0.X (with a subnetmask of 255.255.255.0) is a perfectly legit
> > address, as long as X isn't 255 or 0. Those are reserved for the
network
> > and broadcast addresses respectively.
> >
> > You can have 0's and 255's in the network part of the IP setup, and you
> > CAN also have them in the host part as well, if you're dealing with a
> > "strange" IP range.
> >
> > Try giving this a read: http://www.ipprimer.com/addressing.cfm
> >
> > And if you still have questions after that, come back, and we'll try and
> > get em answered.
> >
> > Matt Gibson - GSEC
> >
> >
> > "oldguy" <(E-Mail Removed)> wrote in message
> > news:ukSPK%(E-Mail Removed)...
> >> Hi All,
> >>
> >> I hope this is the correct newsgroup for this question.
> >>
> >> I have come accross conflicting descriptions about some limitations
> >> concerning IP adressing.
> >>
> >> To make it short, I will directly jump into my confusion.
> >>
> >> I have found out that the DHCP scope of my local network is set by
> >> someone as 10.0.0.4 thru 10.0.0.99
> >>
> >> In an article on the Internet, I have read that 10.0.0.x is not exactly
a
> >> legal adress, as well as 10.255.255.x
> >>
> >> On the books that I read, I come accross some examples which give
> >> 10.0.0.4 and so on.
> >>
> >> I understand that neither the network ID or the host ID cannot be 0 or
> >> 255. I'm not sure if this means the ID as a full expression, or any
> >> single octet in the ID.
> >>
> >> What I want to know is, staying strictly with legal limits, can I use
> >> this scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?
> >>
> >> I will further appreciate pointers to a (THE) authoritative
lecture-type
> >> document freely available in the Internet (not the RFC's)
> >>
> >> Thanks,
> >> Engin
> >>
> >>
> >
> >
>
>

Thank you Phillips, for the recommendation. Indeed, I was thinking of doing
it exactly as you described. I don't understand why the current scope was
created as it is, because there is no other factor which may have dictated
it.

Regards,
Engin

"Phillip Windell" <@.> wrote in message
news:%(E-Mail Removed)...
> Additional to the other good comments,...I would recommend you use the
> Scopes differently,...just as a good practice. Have the Scope use the
> entire IP# as it is specified by the Mask. For example a 24 bit mask
> (255.255.255.0) would give you the range of 10.0.0.0 - 10.0.0.255. After
> you drop off the Net ID and the Broadcast address you will get 10.0.0.1 -
> 10.0.0.254.
>
> So you create the Scope with the full Range and then use Exclusions to
> trim
> it down to what you wan the DHCP Server to pass out to other machines.
> Address within the Exclusions would be used for statically addressed
> machines and other netwok devices.
>
> Eaxmple of a Scope
>
> IP Range: 10.0.0.1 -- 10.0.0.254
> Exclusion #1: 10.0.0.1 -- 10.0.0.25
> Exclusion #2: 10.0.0.200 -- 10.0.0.254
> This gives a leasable range of 10.0.0.26 -- 10.0.0.199
>
> You can also include WINS, Default Gateway (Router), and DNS Settings out
> to
> machines with the Scope.
>
>
> --
>
> Phillip Windell [MCP, MVP, CCNA]
> www.wandtv.com
>
>
> "oldguy" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Many thanks Matt, particularly for the pointer.
>>
>> As a last check, I would say that as long as I'm not messing around with
>> Internet and I keep myself confined to my little local "cage", I am
> allowed
>> to do anything (well, almost) that I want, as far as the IP addressing is
>> concerned. Is this correct?
>>
>> Regards,
>> Engin
>>
>>
>>
>> "Matt Gibson" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>> > Okay, I'll try to explain
>> >
>> > 10.X.X.X is what's known as a private address range. They're
>> > considered
>> > non-routable by the internet as a whole, and are used to create private
>> > networks. The same goes for 192.168.X.X and 172.16.X.X
>> >
>> > 10.0.0.X (with a subnetmask of 255.255.255.0) is a perfectly legit
>> > address, as long as X isn't 255 or 0. Those are reserved for the
> network
>> > and broadcast addresses respectively.
>> >
>> > You can have 0's and 255's in the network part of the IP setup, and you
>> > CAN also have them in the host part as well, if you're dealing with a
>> > "strange" IP range.
>> >
>> > Try giving this a read: http://www.ipprimer.com/addressing.cfm
>> >
>> > And if you still have questions after that, come back, and we'll try
>> > and
>> > get em answered.
>> >
>> > Matt Gibson - GSEC
>> >
>> >
>> > "oldguy" <(E-Mail Removed)> wrote in message
>> > news:ukSPK%(E-Mail Removed)...
>> >> Hi All,
>> >>
>> >> I hope this is the correct newsgroup for this question.
>> >>
>> >> I have come accross conflicting descriptions about some limitations
>> >> concerning IP adressing.
>> >>
>> >> To make it short, I will directly jump into my confusion.
>> >>
>> >> I have found out that the DHCP scope of my local network is set by
>> >> someone as 10.0.0.4 thru 10.0.0.99
>> >>
>> >> In an article on the Internet, I have read that 10.0.0.x is not
>> >> exactly
> a
>> >> legal adress, as well as 10.255.255.x
>> >>
>> >> On the books that I read, I come accross some examples which give
>> >> 10.0.0.4 and so on.
>> >>
>> >> I understand that neither the network ID or the host ID cannot be 0 or
>> >> 255. I'm not sure if this means the ID as a full expression, or any
>> >> single octet in the ID.
>> >>
>> >> What I want to know is, staying strictly with legal limits, can I use
>> >> this scope of 10.0.0.x, or should I make it, say, 10.1.1.x ?
>> >>
>> >> I will further appreciate pointers to a (THE) authoritative
> lecture-type
>> >> document freely available in the Internet (not the RFC's)
>> >>
>> >> Thanks,
>> >> Engin
>> >>
>> >>
>> >
>> >
>>
>>
>
>

"oldguy" <(E-Mail Removed)> wrote in message
news:%(E-Mail Removed)...
> Thank you Phillips, for the recommendation. Indeed, I was thinking of
doing
> it exactly as you described. I don't understand why the current scope was
> created as it is, because there is no other factor which may have dictated
> it.

There are a lot of "bad practices" that also just happen to "work".

--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com