CNAME or A record for separate host name ?
JF Mezei
my system.
He is using whatever domain name registry service. Right now, I have defined
my host with dyndns.org.
lets say "my" host name is chocolate.dyndns.org.
His is www.hotpastry.ca
Both point to the istop provided fixed IP address (which belongs to ISTOP and
reverse translates to an istop customer name such as cocoa.mtl.istop.com)
Should www.hotpastry.ca be a CNAME (alias) to chocolate.dyndns.org or should
it be a full fledged A record pointing to my IP address directly ? What is the
difference between the two in this particular context (both are
defined/registered totally separately with different registrars, different DNS servers).
Ben Kennedy
JF Mezei <jfmezei...@istop.com> wrote:
> Should www.hotpastry.ca be a CNAME (alias) to chocolate.dyndns.org or should
> it be a full fledged A record pointing to my IP address directly ? What is
> the
> difference between the two in this particular context (both are
> defined/registered totally separately with different registrars, different
> DNS servers).
I am by no means a pro DNS guy, so someone feel free to amend my advice.
I think though that in practice it shouldn't make much of a difference.
A CNAME will be easier to maintain, since if you need to re-point the IP
for both names you only need to change it in one place. However, for
his name to resolve will require that your DNS also be working; a direct
A record would obviate that.
Also keep in mind that if you are setting up MX for either domain, the
MX must point to an A record and not a CNAME, according to RFC.
(many bystanders will now be wondering, WTF?)
-ben
JF Mezei
> Also keep in mind that if you are setting up MX for either domain, the
> MX must point to an A record and not a CNAME, according to RFC.
Thanks for that information.
However, since www.hotpastry.com and chocolate.dyndns.org would be served by 2
different dns servers, is it correct to state that resolving www.hotpastry.com
would require a connection to one DNS server which would then tell it to
lookup chocolate.dyndns.org, which would then require a lookup to see who is
the dns server for dyndns.org, connect to it to find the ip address ?
I guess in practice, the overhead isn't really noticeable ?
Laurent
In practice, whenever you have a chance to eliminate someone in the loop, do
it. If for some reason dyndns's server got slow one night, people asking to
visit hotpastry would suffer that slowdown as well. The beauty of having a
fixed IP address is that you can skip dynamic dns hostings, therefore
eliminating one more query in the process. When everything runs smoothly,
this would go unnoticed, but this is the internet. The only smooth thing
there is is how spam infiltrates the world!!
Laurent
Madonna
"JF Mezei" <jfmezei...@istop.com> wrote in message news:3F26D63F...@istop.com...
DNS delays are quite noticeable.
Put one of your favorite websites's IP in your hosts file and notice.
(I guess it's not a good idea however if the site is load balancing).
Marcel
news:3F26D63F...@istop.com...
| Ben Kennedy wrote:
| > Also keep in mind that if you are setting up MX for either domain, the
| > MX must point to an A record and not a CNAME, according to RFC.
|
| Thanks for that information.
Most of the time, an MX that points to a CNAME will work, but on the odd
chance, DON'T DO THAT.
| However, since www.hotpastry.com and chocolate.dyndns.org would be served
by 2
| different dns servers, is it correct to state that resolving
www.hotpastry.com
| would require a connection to one DNS server which would then tell it to
| lookup chocolate.dyndns.org, which would then require a lookup to see who
is
| the dns server for dyndns.org, connect to it to find the ip address ?
chances are that your resolving dns server will already know about who
serves dyndns.org (and I would guess that they are *really* good given the
popularity of dyndns.org). So, that one query less.
It really depends on the frequency at which the A record will change. If it
nevers changes (static IP), there will be a slight difference (a few more
lookups), so an A record could be a tiny bit faster. It it changes often, it
then becomes an administrative burden to synchronize the second A record.
The point about dyndns.org's NS servers availability / dependance is also to
be taken into consideration.
| I guess in practice, the overhead isn't really noticeable ?
It is, for the first query to a slow or busy server. Then it is cached on
the querying server (your server). In chocolate.dyndns.org's case, it will
be cached "locally" for 4 hours. In the long run, it's not really
noticeable.
(Ben - your answer was correct and complete)
Marcel.