Jay Moore ([EMAIL PROTECTED]) wrote: > On Mon, Dec 29, 2003 at 03:06:23PM -0700, the entity calling itself Edward A. > Gardner stated:
> > I don't really understand so-called dynamic DNS, other that what seems self
> > evident from the name. But wouldn't that provide a way to get around such
> > blocking and send mail from dynamic addresses?
>
> I don't understand the term either.
Dynamic DNS service is a one-way (domain name -> IP address) service
to help people with dynamic IP addresses run services. It uses a
third party DNS server with a very short Time To Live.
Example: Alice wants to run a low-volume web site on her cable modem
which uses DHCP to get a dynamic address. She signs up with an
imaginary dynamic DNS service called dyno-dns.com (which may or may
not charge her a fee). She chooses the hostname "alicesrestaurant".
Now, she "owns" the FQDN "alicesrestaurant.dyno-dns.com". It's an A
record in a DNS zone controlled by the registrant of dyno-dns.com, with
a very short TTL (usually on the order of 60 seconds). When she brings
up her Internet connection (typically at boot time), she gets her
dynamic IP address from her ISP. Then she runs some program on her
local computer (a perl script, etc.) which transmits her hostname
("alicesrestaurant"), her current IP address, and her authentication
credentials to dyno-dns.com. dyno-dns.com updates their DNS zone file,
and then voila! Her friends can now reach her web site on her dynamic
IP address just by going to http://alicesrestaurant.dyno-dns.com/.
This is a one-way service, because typically she will have no control over
the PTR record for her address (the IP -> name translation). So, looking
up alicesrestaurant.dyno-dns.com will reveal an IP address, but looking
up that same IP address will give unpredictable results (either no PTR
record at all, or something like "host-1-2-3-4.la.ca.big-cable-isp.com").
This really has nothing to do with spam, AFAIK.
--
Greg Wooledge | "Truth belongs to everybody."
[EMAIL PROTECTED] | - The Red Hot Chili Peppers
http://wooledge.org/~greg/ |
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