[clue-tech] DNS lookups take a looooooong time SOLVED!

[Ken MacFerrin]

Nate Duehr wrote:
>> Ah.. You shouldn't have to spoof your MAC address.  This situation can
> 
> He shouldn't have to spoof at all, and spoofing a MAC address
> shouldn't have any effect on performance at all.  I'm still trying to
> figure out how a Layer 2 addressing change can speed up a Layer 3
> protocol.  Very skeptical here... something else was going on that
> wasn't seen/understood.
> 
> Any "Comcastic" folks lurking that want to explain how a network
> design could be so dumb as to route DNS Layer 3 packets slower if they
> come from the so-called "wrong" MAC address?
> 
> Is this an artifact of some kind of QoS setup that's trained to slow
> down service for anyone not sending their "registered' MAC address?
> Or perhaps STP (spanning-tree protocol) was turned on/off somewhere it
> should/shouldn't have been and a port was confused about where it was
> hearing the PC's MAC address coming from -- Layer 2 loop fighting with
> STP?
> 
> Of course, I'm an old curmudgeon and find filters and/or QoS based on
> Layer 2 to be utterly retarded of the ISP to implement anyway.
> Obviously if a SOHO router can spoof a MAC address automatically at
> the click of a checkbox, whatever's really causing the speed issue is
> utterly and completely bypassed by people smart enough to code SOHO
> routers with the ability.
> 

The modern DOCSIS specs do allow for extensive QoS at the MAC layer but
my experience is that they typically control this using the cable modem
HFC MAC, not the device behind it.  Each time you reboot the CM it
checks for a new config file via TFTP, and based on your account
settings it will receive the appropriate "standard" or "premium" settings.

I still can't understand what happened in Chris' case.  When I
previously had Comcast I paid for the "premium" tier service and changed
the device behind my cable modem many times without issue (as long as I
rebooted the CM).  I did have to call Comcast and re-register when I
upgraded my CM once but not for changing the device behind it.

-Ken