Downtime, DSL Problem

Late this morning, there was a high amount of audible static on my phone line, which probably also affected my DSL. I have written at length, that I host my own site, on my home computer.

Between about 10h20 and 11h20, my DSL connection was on the fritz, probably in association with the static noise I was able to hear on the phone. This also caused my site and my blog not to be accessible to the Internet.

The temperature outside was -19°C, and that may have played a role.

In this case, there is no point in blaming “DynDNS” for what happened, because if the connection is gone for an hour or longer, the Update Client program will stop making frequent attempts to update my IP address into public view. It just happened.

I apologize for any inconvenience.


(Edit : ) My log files indicate, that there was a change in IP address as well, between 3h00 and 4h00, which the DynDNS Update Client program updated to its server routinely – as I was sleeping – and which did not seem to result in considerable downtime at all.


IP Update Failure, Downtime

When we host our Web-sites on professional services, we benefit from the paid advantage, that professionals also make sure there is little or no downtime of their servers. But as I have written before, I host my site, and my blog, on my computer at home. And one component of what makes that possible, I wrote about here, which is called “DynDNS”.

Around 15h00 this afternoon, while I was not home, my ISP carried out a routine IP address change, since I do not own my own IP addresses. There was nothing wrong with the fact that the ISP did this. But my DynDNS Update Client program, which runs on my computer, stupidly and naively failed to update my IP address with the DynDNS servers, even though all my credentials are properly stored on the client.

For that reason, my site and blog were inaccessible to the Internet, until about 17h05, which was the time I came home, to find that to my surprise, there had been no blackout, and no ISP disruption of any kind.

Sometimes, the DynDNS Update Client program goes into a frozen state, in which it cannot function. When I got home this afternoon, that was the state this program was in.

Granted, I can always log in to my DynDNS account, and update my IP addresses manually – when I happen to be home and aware of what is going on. But the whole point of having an Update Client program, is that this should happen automatically, which just this once, it failed to do. I currently have Linux version 5.4.2 of this program.

I apologize for any inconvenience.



How DynDNS Works

You could face the following problem. You could be intending to set up your own Web-server, for it to be visible to the public, on your home computer. You could have an ISP, which assigns and reassigns you IP addresses which they own, and which therefore, you do not own as static IP addresses.

You could have taken the step of installing a Web-server on your machine, as well as to do “Port Forwarding” on your router, meaning that the router listens on Port 80 on the WAN, and forwards all incoming connection attempts to that port, to the host machine on your LAN.

You would now have the problem that your Web-site needs a URL, with a domain name, which anybody on the Internet can use, to access your Web-server. After all, your IP address can change, and it would not be practical to update people directly, with your new IP addresses.

There is a freemium service on the Web, which would be able to help you with that problem. When we give our Web-browsers a URL with a domain-name, the browser accesses a public DNS server, to look up the IP address of the Web-site, associated with that domain name. “DynDNS” offers a specialty service, by which its members have ‘a Dynamic DNS service’. Its members install an update client on their machines, and reserve a domain-name with DynDNS, which is to be associated with their potentially changing IP address, continually.

Whenever the ISP changes our IP address, the update client on our computers detects this, and logs in to the DynDNS account we have. Then, the update client notifies DynDNS of the new IP address, and DynDNS has the connections with the public network of DNS servers, to propagate the new IP address. It is the responsibility of DynDNS, that requests for domain-names which its members hold, from Web-browsers, be answered with your updated IP address.

The Web-browser is never notified in any way that your IP address or domain name are different from ones with static IP addresses, it simply receives the IP address from its subscribed DNS server, that is your WAN address, and connects to it.

Further, if you have registered a host-name, as they call it, with DynDNS, there is no specific reason why you would need to listen on Port 80 always. Your purpose could be to make other services publicly-accessible, which listen on other port numbers, which you have instructed your router to forward to some machine on your LAN.

This is the arrangement by which I host my own Web-site, and additional services, from my home computer.


dirk@Phoenix:~$ host has address has IPv6 address 2001:0:53aa:64c:d1:32e7:b9cc:d8a8 mail is handled by 10




The problem with my DSL is worse than I thought.

I have paid closer attention, to the ‘Internet Connection Failure’, which I just posted about Here. Even though the public cannot read my blog right now, the way I am set up, still allows me to write entries.

When I checked my DSL more carefully, I noticed that I do not have a dial-tone. And, every half hour, to every two hours apart, the DSL connection is dropping out on me. This does not seem to have been a problem with the router per se.

For the past few days, Montreal has been experiencing continuous, heavy rainfall, starting on ?Tuesday? The weather is going to stay this wet, until tomorrow (Sunday). I suppose that what can happen, is that excess water can seep into the cables, and can cause those DSL wires with the weakest insulation to fail. I hear crackling noises when I listen on my phone, for an expected dial-tone.

Certain services are more sensitive than others, to errors in the transmission of packets. It would seem that the Teredo gateway has no tolerance for those at all, for which reason it was dropping my client connection frequently.

And, had I left things as they were, the ‘DynDNS’ service would have attempted inexhaustibly, to keep associating new IPv4 addresses with my URL, even as the modem was dropping the connections, and establishing new ones.

The only responsible thing I was able to do in response, was to shut down my DynDNS service for now, to avoid future, excessive update-requests, which also means that the public cannot be reading this as I am writing it.

The technician from my ISP is scheduled to come by on Tuesday, to see what can be done to remedy this problem. And my blog and site will have to remain offline until then.