[lug] comcast and multiple IPs

Mr Viggy viggy at peakpeak.com
Tue Jun 8 20:13:16 MDT 2004

MAC address is not part of the TCP/IP frame, so there's no way they can
count your MAC address.  If you look at the OSI model, the MAC address
is in a lower layer then the protocol layer.

While, yes, they can count MAC addys, but, if you plug a
firewall/NAT/DHCP (I did leave out DHCP in my last post) server in
between Comcast's modem and your other computers, all Comcast will see
is the one firewall.  MAC is used for two Ethernet cards to talk
directly to each other, so if you're communicating through a router of
some sort, you cannot be talking on the hardware layer.

Oh, on another note, one of my co-workers called Comcast and asked them
if they were only allowing one PC or one IP address per household.
Nobody could answer his question.


> D. Stimits wrote:
>> ...
>>> Basically, if you have a firewall that also does NAT, you *are* only 
>>> getting one IP address from them.  There's no real way they can tell 
>>> that you have multiple computers.  It looked like Comcast was offering 
>> ...
>> I have to wonder if in some cases of NAT the MAC address pops up. 
>> MAC's are how they decide number of computers, because MAC addresses 
>> are also how DHCP identifies it. If you swap out a NIC in your comp, 
>> they will think you have 2 comps, even if you have only 1. If you 
>> already have 2 NIC's and swap which one the cable plugs into, the same 
>> story, they will accuse you of having 2 comps. I realize that for 
>> normal NAT purposes the other comp's MAC will not show up, but I have 
>> to wonder if this is always true.
>> D. Stimits, stimits AT comcast DOT net
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