[BALUG-Admin] IPv4 IP changes coming! - comcast business reverse IP

[Michael Paoli]

Cool, good to know.  If you know where that "reverse" DNS can be changed
in some GUI somewhere, that'd be quite useful.  I'll also look/poke
around in there some more - may well be it's there, ... just not that
clearly visible nor easy to find.

As for IPv6, since for years I've been doing that via tunnel
(he.net's https://tunnelbroker.net/), for at least the shorter
term, that remains the same (of my two such tunnels, already moved
the less critical over, so it's now being tunneled through the
Comcast Business connectivity).  That also means all the IPv6
IPs I'm presently using and care about remain exactly the same.
So, one less thing to be juggling at the same time.
Looks like Comcast Business likely provides IPv6 well enough ...
but I haven't looked at it in much of any detail ... yet.
Longer term I'll probably move to/towards the native IPv6,
but tunnel is "good enough" for now ... and so long as that
(also) works, I can keep it around for backwards compatibility
(but not much for redundancy, as it travels / will be traveling
via same link and ISP).

Oh, and for the curious, my high-evel outline of the ISP switch-over
process and status currently looks roughly like this (
o to do
- partially done or in progress
x done
):
x new IPs added to hosts
x conditional (from) routing added to hosts (from new to use new gateway)
x DNS slaves updated on status once masters available on new IPs
x "glue" records updated
- new IPs added to DNS (some may go in phases)
- "reverse" DNS updates
o SMTP "tests" / warm-up
- "new" default route; conditional (froms): add "old"; drop "new" (superseded)
- DNS notify IPv4 source updated
- "old" IPv4s removed from DNS in advance (>=TTLs) of old IPv4  
decommissionings

> From: Al <awbalug@sunnyside.com>
> Subject: Re: [BALUG-Admin] IPv4 IP changes coming! - comcast  
> business reverse IP
> Date: Fri, 13 Dec 2019 07:43:29 -0800

> FYI I did eventually manage to set the inverse IP names for my 13  
> IPs from Comcast Business.
> And IIRC I think I did eventually manage to do that online (through  
> the worst GUI on the planet),
> but I'd have to go back and check to see if that is (still) true.
> They don't delegate lookups like the big boys, but each of the 13  
> names can be set to whatever I like.
> (And forget DNSSEC.)
> example:
> dig any 52.105.242.50.in-addr.arpa
> ;; ANSWER SECTION:
> 52.105.242.50.in-addr.arpa. 60  IN      PTR     ns2.sunnyside.com.
>
> On IPv6, I haven't attempted to do that yet.  Might be worth a shot.  
>  I think at the time Comcast was
> still discovering IPv6, and mostly letting the modem vendors run things.
> It might be better now, although 5 years is probably much too soon  
> for a change on that.
>
> AT&T actually does it right (and no, I don't mean u-verse).
> Al