Cheap Gigabit switch will allow DHCP thru it?

[Paul Lussier]

"Ben Scott" <dragonhawk at gmail.com> writes:

> On Dec 29, 2007 12:31 PM, Bruce Labitt <bruce.labitt at verizon.net> wrote:
>> I'm looking to add another hdhomerun tunerbox to my myth setup.  I have
>> a DHCP server running to give the existing tuner its IP address.  Can I
>> add a cheap gigabit switch to add the other tuner?
>> Will the requests for IP address be routed to the server properly?
>
>   Short answer: Buy the switch and it will likely just work.  If it
> doesn't just work, it will be a simple matter to make it just work --
> just ask here.
>
>   Longer answer:
>
>   A switch is what is called a "layer 2" device; all it does is
> forward Ethernet frames.  IP, DHCP, and friends are all "layer 3" or
> higher.  So DHCP and everything else will not even be aware that the
> switch is there.  It's all one, big happy Ethernet network.

If memory serves (though, often times, sadly, it serves incorrectly :)
DHCP is heavily dependant upon (r)ARP (specifically when combined with
PXE), which kinda sorta sits in a no-where land between layers 2 and 3
(like ICMP).  That being said, it's also heavily dependant on UDP
broadcasts (DHCP_DISCOVER and DHC_PREQUEST), which should also
traverse switches just fine.

>  I seem to recall that MythTV uses a broadcast packet to find the
> HDHRs.  If that is the case, the IP address of the HDHR won't matter
> -- the broadcast packet will reach both of them, and MythTV will have
> to tell them apart.

If that's the case, then the switch shouldn't interfere at all...

-- 
Seeya,
Paul