[mythtv-users] Static IP vs. DHCP

Brian Wood beww at beww.org
Wed Dec 26 18:38:55 UTC 2007


Chad wrote:

> 
> Sounds about right.  The same holds true for most networks.  A single
> point of failure (a lone DNS server) would bring down the entire
> network if every device was configured using host names instead of an
> IP.  It eases simplicity (you plug in a friendly name instead of a
> cryptic IP) but gives you another thing to worry about.  By making
> your DNS, DHCP and Myth server "all-in-one" you kind of negate the
> potential of monitoring multiple hardware failures (service failures
> may still occur); meaning if your motherboard dies, you don't need a
> working Mythbackend, a working DHCP or a working DNS server (for
> Myth's purposes) since any one of these means failure all around
> anyway.  In a real world situation you typically don't have all those
> services on a single host, and DNS failure doesn't bring down your
> services (maybe your user's interaction with those services though)
> and they can keep right along working without DNS, all assuming you
> did use the IP of the systems instead of their DNS resolved names.
> 

If you are using "private" (RFC 1918) addresses, and want to use names
and not numerical addresses, you have to use either a "private" DNS
server, /etc/hosts files or even NIS (sometimes called YP or "yellow
pages". The only way to protect against failure would be to use multiple
servers or methods.

To do DNS properly you should have a least two servers on totally
different network segments, but even a lot of ISPs do not follow that rule.

If you are using "real" addresses there are several outfits that will do
DNS for you very cheaply or totally free. There are even outfits that
will do DNS if you have a dynamic IP address from your ISP.

The time to query an off-site DNS server for a single lookup is minimal,
assuming a reasonably fast network connection. You could run a
caching-only DNS server to reduce the time for subsequent lookups.

But in any case I doubt that many Myth systems suffer from problems with
machine addressing, there are just too many ways to do it easily.

beww



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