IMHO, one should never be shortsighted and think that they'll never be
connected to the internet. Of course, even if you use RFC1918 addresses and
you end up merging with another company using RFC1918 address, you'll
probably end up renumbering. But at least start with something that you can
reasonably assume you won't have to change. Mainly, start with .50.x or
higher for your subnets if you think you'll ever merge with another company.
USE DHCP! If you need statics, get the MAC address and assign the static
address in the DHCP server.
That way, you have a decent change of not having to renumber, or when you
do, it'll be easier. Why am I harping on this? Tonight's project:
re-number 4 sites, all numbered with 192.168.1.0/24 (4 different newspapers
bought by one company). At least I get to do it all remote from the router
side of things. All I have to do is remote in, set the DHCP & WINS from
disabled to automatic (I've already configured them all), change the IP
address (good thing NT/2k can handle this on the fly and just let me
reconnect, then reboot for DHCP/WINS service to notice the change). Then
all the support grunts get to run around to 1000 PCs between all these sites
and change them to DHCP. I'm sitting in my PJs on my couch, by the way, so
I'm not too grumpy compared to the rest of them. Of course, being a
newspaper, we can't get started until late tonight. *sigh*
--
Jason Roysdon, CCNP/CCDP, MCSE, CNA, Network+, A+
List email: [EMAIL PROTECTED]
Homepage: http://jason.artoo.net/
Cisco resources: http://r2cisco.artoo.net/
<[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Well, if the network isn't connected to the Internet, and isn't going to
> be, then you can use whatever addresses you like. Not recommended to use
> any old class A (just because requirements always change - you may have to
> merge with another network, you may need Internet connectivity in the
> future etc), but it will work.
>
> You can use NAT (Network Address Translation) or PAT (Port Address
> Translation) to translate your 'inside' network addresses (i.e. anything
> you choose) to legal assigned Internet addresses. This can be done either
> statically or dynamically. Not all protocols work with NAT; for example
if
> the IP address is contained in the data portion of the application packet,
> NAT needs to be aware of that and needs to change it there as well (which
> may mean re-calculating checksums etc - messy).
>
> It is generally recommended (actually, I think it is universally
> recommended) that if you have a choice, use RFC1918 Private addresses if
> you're not using 'real' (i.e. allocated to you) addresses. These are
> address blocks set aside and not allocated to anybody. 10.0.0.0/8 is the
> class A address defined as a 'private' address block.
>
> Why might you use some other class A? Well, we use multiple unassigned
> class As in our internal network. It makes it easier to have an
addressing
> scheme that uses the octet boundaries - you don't need to be able to think
> in binary to be able to work out what office a particular address refers
> to. On its own, that isn't a very good reason - but our network
addressing
> scheme was implemented before RFC1918 came out, and it's a large,
> geographically distributed network with several hundred remote sites (very
> remote, some of them). The effort and pain that would be involved with
> re-addressing is, so far, greater than the effort and pain in working
> around the problems caused by using 'illegal' addresses. Sooner or later
> we're probably going to have to readdress, but personally I'm hoping
> somebody comes up with some other solution ;-)
>
> JMcL
> ---------------------- Forwarded by Jenny Mcleod/NSO/CSDA on 16/01/2001
> 12:37 pm ---------------------------
>
>
> Jennifer Cribbs <[EMAIL PROTECTED]>@groupstudy.com on
16/01/2001
> 10:21:57 am
>
> Please respond to Jennifer Cribbs <[EMAIL PROTECTED]>
>
> Sent by: [EMAIL PROTECTED]
>
>
>
> To: "John Pusledzki" <[EMAIL PROTECTED]>
> cc: [EMAIL PROTECTED]
>
>
> Subject: RE: subnetting and tcp/ip and Private addressing Help!
>
>
> There is such a thing as private addressing where you can have any address
> you
> want, but you usually have something set up at the router that dynamically
> assigns you an address space when you leave your network, such as out in
> the
> internet world. That way you remain legal... And the addressing within
> your
> network is your own business then. I do not know how this actually works,
> but
> I do know this is an option. I think I read something about NAT providing
> this service. The group would know about this. I do not. Chuck is a
> good
> one to ask on this issue...
>
> The question is how come someone can have a class a address that internic
> did
> not assign. Anybody??
>
> Jen
>
>
>
> ------------------------------------------------------------
> Have a Good Day!!
> Jennifer Cribbs
> [EMAIL PROTECTED]
>
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