On Wed, 26 Dec 2001, Brian Densmore wrote:

> Well, for one thing, dynamic IP addresses are very useful for system
> administrators of medium to huge networks. Maintaining static IP
> addresses for a large network can be time consuming, even with
> automation scripts. Secondly, I think [correct me if I'm wrong] Gerald
> was trying to imply that a dynamic address could be useful against
> attacks on a single IP address.

You're correct.  BTW, from an ISP perspective, static IPs are a HUGE
hassle.  Most ISPs are forced by their upstream provider, ARIN, or both to
be very efficient about their address space usage, and don't have a much
space at their disposal at any given time.  This means that they have to
reallocate address blocks on a regular basis.  This is easy if your access
users are all dynamic - you move addresses in and out of your pool(s) as
needed.  You can also use a relatively small pool of addresses to serve a
large amount of customers (this works for dialup more so than cable and
DSL).  Doling out static addresses throws a wrench in both of these - your
static users are Yet Another Thing you have to worry about when
reallocating space, and these same (often high-maintenance) users are
sucking up your address space so that they can run a web/mail/FTP/DNS
server on the cheap.  Personally, I don't fault Time Warner (or any other
ISP) for charging a premium for static blocks.  I'll stop ranting now.

> Which brings up an interesting question. Can a DHCP server re-assign an
> IP address to a currently connected device, without that device having
> to bring networking down and back up? This would be a useful tool to be
> used in combination with a firewall.

I don't think DHCP currently support this - as far as I know, the RFCs
only specify client-initiated configuration requests.  I think it's part
of the DCHP-for-IPv6 draft spec, though.

> Brian
> 
> > -----Original Message-----
> > From: Marvin Bellamy [mailto:Marvin.Bellamy@innovision.com]
> > Sent: Wednesday, December 26, 2001 9:28 AM
> > To: Gerald Combs
> > Cc: kclug@kclug.org
> > Subject: Re: OT-Re: test post
> > 
> > 
> > Not at all being a smart ass, but when?  I've run into some 
> > very useful 
> > commands that are unfortunately not smart to expose in the 
> > spammer era 
> > (SMTP VRFY for example)...
> > 
> > Gerald Combs wrote:
> > 
> > >Sometimes a dynamic address can be a good and useful thing:
> > >
> > >----
> > >
> > 
> > 
> > 
> > 
> > majordomo@kclug.org
> > 
> 
> 
>