Thu 29 Apr 2010
DNS Agent updated
Category : Technology/DNSAgent1dot0dot1.txt
Our server was not reachable for 5 hours last night. I only discovered it early this morning at 5.00 am when I woke up.
Turns out that at around midnight, our public IP address had a new lease of its IP address. So the IP address changed but DNS Agent, somehow, was not able to update dyndns.com with this latest IP address.
But why? It had been working very well for a couple of months already. By building our own dynamic DNS update mechanism, using DNS Agent, I'm able to update dyndns.com very quickly, restricting our downtime, whenever our public IP address changes, to not more than two minutes.
So why didn't it update dyndns.com this time? Turns out that there seems to be a change at dydns.com's dns server - it stopped responding to ping requests. I designed DNS Agent to ping the DNS Server to make sure it's alive before wasting time trying to contact a particular port. But some admins could turn on "stealth mode", like on our Macs, and make the server refuse to respond to ping requests. That looks what what happened.
So I've built a new version of DNS Agent that will skip the "ping" step but DNS Agent will still make sure that the server will respond to the port relevant for DNS updates before trying to issue the update.
DNS Agent 1.0.1. is available for download now.