[rescue] Static IP! Now what?

John Hudak jjhudak at gmail.com
Thu Apr 6 08:20:05 CDT 2017

> What else is a static IP good for?
Many ppl have already responded with good points.  I just want to point out
a subtly of the overloaded term 'static IP address'...
Static means that the IP address of the device itself does not change.  The
subtly is where it gets the assignment from.
In the 'bad old days'  device IP addresses were manually assigned and
configured on the client device. The evolution of routers provided a
capability called 'reservation tables' in which the user specified in the
router configuration:  the MAC and the associated desired LAN IP address.
This arrangement provided the outward appearance of a static IP address but
it was managed by DHCP.  Depending on your computing environment, this
arrangement offers many of the advantages of manually assigned/managed
static IP addresses.  There are some drawbacks, some of which are the
router becomes a single point of failure, increased 'boot time' of a large
network and access to the router to see the assignments.
The two types of IP address management approached can coexist on a network
but configuration and operation of the network can become a little
complicated...that's a topic of another much longer discussion.

On Wed, Apr 5, 2017 at 11:45 AM, Mouse <mouse at rodents-montreal.org> wrote:

> > [...]
> > What else is a static IP good for?
> Basically, anything a dynamic IP is good for, plus assorted things
> where you want to be reachable at a fixed IP.  Mostly, in practice,
> this means you can run your own just-about-anything: DNS, mail, web,
> VPN, FTP, what-have-you.  (I'm assuming there aren't still
> provider-imposed restrictions like "can't run servers" or "no outgoing
> TCP to port 25".)
> If you're stuck with only one IP, there are additional headaches, but
> you said you'd have a /29, so those shouldn't be issues.  Depending on
> how much you care about such things, you might want to bug them about
> IPv6, too.
> > [...], and I'm curious about how well VOIP will work for our fax
> > line.
> Based on my tests, either really well (if it gets converted to T.38
> before getting to you) or really crappy (if it is still trying to use
> POTS fax codecs).  The codecs originally used for fax were designed to
> deal with the sorts of errors POTS introduces.  SIP introduces errors
> too, but they tend to be completely different errors (typically
> dropouts rather than corruption, roughly speaking), so different coding
> schemes are called for.  POTS fax works fine provided you have
> absolutely zero data loss, but even a single missed data packet plays
> merry hell with designed-for-POTS fax codecs.
> ...that's assuming your VOI is SIP.  If not, I'm not really competent
> to comment, except that similar remarks _probably_ apply.
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