TTL For a Dynamic IP DNS Site

[Mark Damrose]

"Ted Smith" <bluearchtop at my-deja.com> wrote in message
news:aptd6o$6t4f$1 at isrv4.isc.org...
>
> Hello,
>
> I wrote a windows service which detects when my IP changes and fires
> off a command to my Bind DNS server which updates the zone file and
> restarts DNS.  This is similar to what DNS2Go, NO-IP, etc do. Anyways,
> it's working fine, but I'm not sure how to make it so other hosts
> refresh my domain name frequently since it will be changing a lot. How
> do sites like DNS2Go do it?

When you are doing dynamic updates, you specify the TTL for that record.
That is the amount of time that others are allowed to hold the data before
refreshing it.  How often does your IP change?  If it's once a month, a TTL
of 6 hours might be sufficient.  If it's once an hour, you may want it to be
5 minutes.

>
> This is what I have? I don't know much about BIND though...
>
> $TTL 120
> @       IN      SOA     ns1.mydyndns.net.
> hostmaster.mydyndns.net. (
>                         2002103109      ; serial
>                         10800           ; refresh
>                         3600            ; retry
>                         604800          ; expire
>                         86400   )       ; default_ttl

This field is no longer the default TTL, it is the TTL for negative caching
(i.e. how long others can cache "this record does not exist" answers.)  1
day is too long for this.

>
> Any suggestions? Thanks.
>