determining if host has a dynamic or static ip address

[Aryeh Friedman]

On Mon, Jun 8, 2020 at 10:46 PM Ernie Luzar <luzar722 at gmail.com> wrote:

> Polytropon wrote:
> > On Mon, 08 Jun 2020 19:34:17 -0400, Ernie Luzar wrote:
> >> I am asking if anyone knows of a way to determine what type of public
> ip
> >> address the host has been ISP assigned [...]
> >
> > That's not exactly easy to tell. You can examine the hostname
> > associated to the IP, and maybe it contains something like "pool"
> > or "dynamic" - in that case, it's usually a dynamic IP from a
> > specific range.
> >
> > There are ranges allocated by the ISPs that they use as a pool
> > for customers' addresses assigned via DHCP (or a different means),
> > for example. You can check if the IP is in such a range. Again,
> > it's up to the ISP how they use such a range, as they could use
> > a subset for addresses that they actually use as static IPs.
> >
> > The "rinse & repeat" method is also not reliable: You could
> > disconnect and reconnect to your ISP, and if you get a different
> > IP each time, it's probably dynamic. If not, it can still be
> > assigned dynamically, so no way to be sure. Some ISPs sometimes
> > "bind" the dynamic IP to the MAC address of the endpoint (and
> > some even use the MAC address as the authentication factor for
> > the customer).
> >
> > More information here:
> >
> > https://whatismyipaddress.com/dynamic-static
> >
> >
> >
> >> [...] by coding a csh script?
> >
> > Why should anyone do this in _C_ shell?!
> >
> > Tom Christiansen: "sh Programming Considered Harmful", 1996
> >
> > http://harmful.cat-v.org/software/csh
> >
> > https://www-uxsup.csx.cam.ac.uk/misc/csh.html
> >
> > I know what I'm talking about, I exactly wrote (and still use)
> > one, in numbers: 1, C shell script. ;-)
> >
> >
> >
> >> Is it even possible?
> >
> > Depends. :-)
> >
> >
> >
>
>
> Is there some ISP standard that blocks dynamic ip address customers from
> being able to pass bridge and vlan info to the public internet while
> static ip address allow that kind of stuff out to the public internet.
>

Short answer: No
Long answer: Unless the dynamic IP's are also private IP's (unroutable
blocks) and the static ones are public IP's (or the reverse is true) then
no you can not tell the difference.   Many ISP's make all their IP's
private for two reasons 1) conserve a scarce non-renewable resource (public
IP's) and 2) make it so people can't host services/sites on their machines
unless they pay for a hosting plan
--
Aryeh M. Friedman, Lead Developer, http://www.PetiteCloud.org