[pptp-server] ARP Binding ?!?

[Steve Langasek]

Tim,

On Tue, Nov 20, 2001 at 09:05:12AM +1100, Timothy Findlay wrote:

> I didn't quite follow the first bit, and I'm no network Guru, but the
> network here (128.x.x.x) was setup long before my time. I know there are
> RFC1819 thingo's set aside for internal networks though (192.168.x.x,
> 10.x.x.x etc. etc.) but as I mentioned, it was all setup before my time.

> Are there actually legitimate 128.x.x.x addresses live on the net are there
> ?? unfortunately I'd have quite an uphill battle changing things as there
> are a few hundred PC's and umpteen servers that would need to be changed.
> and for the most part people have the attitude of "Hey, but it all works
> doesn't it ?"

> Even the poptop VPN does actually work, if I manually go and change that
> proxy-arp file for my internal ethernet (eth1) ... <shrug>.... it's just
> messy, and a pain to do...

The issue with using 128.x.x.x on your network (addresses which are not
assigned to you, unless you're a secret subdivision of BBN
Communications ;) is that they are not reserved as private addresses;
this means that at any time, it's possible that ARIN could revoke the
current assignment and reallocate this network for public use.  And of
course, they wouldn't have to tell you before they did so, either -- so
one day, you'd wake up and find that there was a new section of the
Internet that was completely inaccessible to you.

Of course, the longer you keep your current addressing scheme, the more
infrastructure you'll have in place that will need to be converted when
you're forced to; and of course, if you're like most companies, this
argument will be utterly ineffective at persuading the Powers That Be
until it becomes a material problem. ;D

Cheers,
Steve Langasek
postmodern programmer