[svlug] Comcast SMC cable modem and static IPs

[Christopher Young]

Hello SVLUGers, 

I've just recently moved back to California (from Chicago) and am glad
to be able to turn back on email for SVLUG (I never unsubscribed, I
fully intended to return :D ).

So every time I setup my home network there is also some new problem
to figure out.  I live in Boulder Creek, and I used to have DSL with
PacBell which worked very nicely.  My Cobalt Qube2 was my gateway
and my HTTP/SMTP server for my simple needs.  

Then I moved to Chicago (Oak Park actually) and got DSL with
Ameritch.  Now instead of the Qube being my firewall, I had to use the
router provided by Ameritech and use IP mapping to map my external
static IPs to local IPs.  NAT but on an address level (instead of just
ports).

So now that I've returned, PacBell has become AT&T and I am informed
that they no longer offer DSL to my area because they have 'upgraded'
their services so they no longer offer the lower data rate.  I asked
if they'd send out a tech to test the line and see if it would work
but once past the 20k foot mark, they just won't bother.  Ah well.

So I ended up trying out Comcast.  The data rate is quite nice I have
to say but I'm a bit confused about the static IPs.  I got the 5
statics but am not quite sure how it's supposed to work.  The tech
support person told me today that I could just assign the external
addresses to the machines I wish to be visible to the outside world
and the SMC Cable modem should figure it out.

Well I tried it with my Linux desktop just to see it didn't work so
well.  The strange thing is I was able to ping my desktop from outside
but my pings originating from the desktop to the outside did not
succeed.  

I guess at this point I'm wondering if anyone else has this set up and
has it working.  I'm curious if there is any special configuration on
the SMC that was needed or if I just need the appropriate dosage of
chicken bones and occult incantations. 

The nifty thing that is the port forarding that is configurable
through the web on the SMC allows my email and web traffic to be
directed appropriately but I'd like to turn off those port forwards
and have the servers exposed to the net.

/cky