I have justm changed ISP from a cable ISP provider to an ADSL - - I notice the ADSL ISP changes IP address much more frequently than that of the cable (both are dynamic IPs)
On the Netgear router there is a setting so that my dynamic IP address updates the name that i like it to resolve to - i.e http://123.dyndns.org
will always point to the IP address of my router - but I wonder how often this may update itself, is it reliable?
Reason I ask is that my MX records point to for example: 123.dyndns.org - and if the IP is not updated the mail for my domain name is unlikely to hit my exchange server.
Is there some sort of mail service (free) that can fire an email to me at specific time (perhaps ever 30 mins) so I can see that the mail is constantly working?