couple of questions regarding 'lifeline' and large scale nat...

Joe Hamelin joe at
Sat Feb 11 01:36:44 UTC 2012

On Fri, Feb 10, 2012 at 1:19 PM, Eric J Esslinger <eesslinger at>wrote:

> We're toying with the idea of a low bitrate 'lifeline' internet on our
> cable system, maybe even bundled with a certain level of cable service.
> First question, if you happen to be doing something like this, what bit
> rates are you providing.

Well, a lifeline telephone is effectively 64kb/s, up and down.  Makes me
remember when I had my first ISDN line and was happy to get beyond dial-up

> Second question, though 'real' internet customers all get real IP's, what
> would you think of doing something like this with 'large scale' nat
> instead. Understand, we're only talking about basic internet, something
> like a 256k/96k (or similar) connect, not something that would be used by a
> serious user. (One thing we are looking at is some older dial up users we
> still have, most of which could go onto cable just fine but don't want to
> pay the price).

Force SMTP to something sane, block all the 139, etc. MS ports.  Basic web,
telnet, and ssh.  Set it up like a coffee house.  Use a proxy and make them
register.  It's not like they are chatting 911, ya know.  If they have NAT
issues, then they need a real account.  If they can get to google,
wikimedia, or what ever a high school student needs to research papers,
then they have what they need for a life-line.  Let chat protocols through,
that's low bandwidth.  I'm guessing that this is done as a favor to the
customer that won't/can't pay for a real account.  But let them know it's
not a real account.  This is just to give them a taste of real IP and not a
solution to all their problems.  Shove them a NATted DHCP address and if
they can't figure that out then refer them to the local wizkid or a better
plan with support.  Let them know up front that this is a basic service and
don't expect phone support.  If you're a cable company then they can call
and say the cable is out.

Joe Hamelin, W7COM, Tulalip, WA, 360-474-7474

More information about the NANOG mailing list