[ale] Comcast linux...

[Bob Toxen]

On Tue, Jan 06, 2004 at 09:36:57AM -0500, Yu, Jerry wrote:
> I have a RH linux hooked up to the cable modem (Motorolla surfboard ??4100).
> It always picks up IP/subnet/dns using DHCP just fine.  The RH has been
> upgraded from RH 6.1 all the way to 9.0. Hasn't got around to upgrade to
> Fedora yet.
> Make sure your firewall rules allows DHCP (67/68).
> I can give you the information once I get home. However, the IP you grab
> manually may conflicts with whoever gets assigned by Comcast's DHCP
> server...
Actually, you probably do NOT need to enable DHCP (UDP 67/68) in your
firewall as dhclient (and almost certainly the other DHCP clients) put
the interface in Promiscuous mode to listen.  They need to do this because
otherwise the hardware will filter out DHCP packets as having someone else's
IP address as the destination.  Do "ifconfig" and look for the PROMISCUOUS
flag (unless you have one of the versions of RH that have a broken version
of ifconfig, in which case the script that ships with my book will tell.)

Yet another reason why DHCP is a badly designed protocol.  Who created it
anyway?  The other reason is that it is UDP which is spoofable, rather than
TCP which is not with a decent stack.  Microsoft?

Bob


> -----Original Message-----
> From: Byron A Jeff [mailto:byron at cc.gatech.edu]
> Sent: Tuesday, January 06, 2004 7:26 AM
> To: Atlanta Linux Enthusiasts
> Subject: Re: [ale] Comcast linux...


> On Mon, Jan 05, 2004 at 03:20:48PM -0800, Berlin Brown wrote:

> > I almost have my comcast cable modem setup.  I think I just need a primary
> > dns, nameserver using ips only.  Does anybody have the dns for atlanta
> from
> > comcast, emory area.

> That's an interesting question. Everything for comcast is set up via DHCP 
> right?

> >  

> > I cant find it on the net.  And the people at comcast wont give it to me.
> > Redhat is supposed to pick it up, but it didnt?

> That's real interesting. Actually it just got more interesting as I checked
> my smoothwall machine and it's acting as its own caching nameserver. So
> I don't have the address either.

> BTW the cc.gatech.edu College of Computing server will serve DNS addresses
> to anyone who asks. It's what I always use when I don't know the local 
> address: 130.207.3.207

> >  

> > Funny thing, when the comcast tech came.  At first I never even thought
> you
> > needed a windows machine(havent installed a win machine in 2 years).
> Anyway
> > the guy went nuts over it.

> Not only typical, but it's in your Terms of Service.

> >  I said fine, just leave the modem, 'We can't do
> > that, once you get windows up, we will send another guy out.'  

> Again the standard response.

> > B.S.!, just  leave the modem, Ill figure it out, then he left.

> It's unfair, but makes sense. Here's the facts of the matter:

> 1) The techs only have limited training.
> 2) The customers generally know nothing about computers and networking.
> Usually
>    this gives the techs an advantage, until they come across one of us. ;-)
> 3) It costs money to train for another OS and....
> 4) They can lose their jobs if they leave without it being set up.

> It's a tough life for us Linux folks, but in fact I and appreciate the
> policy because if they did train the Techs (both rolling and phone),
> the cost of service goes up.
The service does not go up.  The $600 a year that one Linux user spends
is more enough to add two lines to the script that the Techs use.

> On the phone I always tell 1st level tech support that's it's a Windows 2000
> box. I patiently explain that it's the cable modem, not my machine. If I
> get to second level I ask "Do you want to hear the truth?". Usually they do,
> but they don't flip out. I ask them what they are looking for and translate.
Yes, the only way I got the MediaMinusOne (that became ComCast) morons to
verify that they miskeyed my MAC address (despite my handing them a printed
copy) was by lying and saying that I hat Windoze95.

> I still find it interesting that no DNS info comes through...

> BAJ