dynamic dns

Downtime – fixed

It looks like at about 6pm on 12th July 2016, our external IP address changed at Norchard (so much for “BT Business – Static IP”) but for some reason our dynamic DNS didn’t catch up.

So the asterisk has been effectively offline since then. Service was restored at around 4pm on 14th July when I noticed it was down!

My phones are still offline (including his C*Net and SipGate numbers) due to some technical glitches at home, but that’s unrelated!

DDNS tracking reliability confirmed

I’ve just been looking at the monitoring for our dynamic dns and it looks like the new update script is tracking our IP changes reasonably well.


The top graph shows the state of our DNS entries. When the line is “high” it means everything is working fine, when the line is “low” it means that our DNS name doesn’t resolve to the right IP address because our IP has changed and the DNS hasn’t caught up yet.

The bottom graph shows how many IP addresses the monitoring has seen per-hour. On a healthy broadband connection, that line should be fairly flat. However, the broadband at Norchard is so flaky that the router drops sync several times a day – getting a new IP address in the process.

So you can see, on the left hand side of the red line – we were frequently losing sync with our DDNS provider with the old script in place. With the new script in place we were out of sync for a 1 minute period yesterday, despite experiencing 7 changes of IP address!

Why is the broadband so flaky? As it gets worse in damp or cold weather, I suspect an earth leakage on one leg of the line caused by a damp joint, or a nick in the cable somewhere between Norchard and the exchange.

However I’ve always been told the Norchard broadband isn’t our responsibility – so I’m not best placed to get that looked into.

The “powers that be” seem hell bent on moving away from BT Broadband to Chess (and if I try and get the BT broadband fixed, they’ll moot that as a “cure”) – although that’s not going to improve matters if it’s the line plant which is at fault.

Which I’m fairly certain it is.

A more robust Dynamic DNS client

For a while now, we’ve been using a lightweight dynamic dns update client which I found on the web somewhere.

It was reasonable, but it doesn’t always play nicely with the BT Broadband router. If it attempted to make an update while the router is rebooting, the BT Broadband router returns an error page, which made the script think it had saved it’s IP correctly.

The practical upshot is that sometimes our IP address would be out of sync until the router had rebooted 2 or 3 times. Luckily for us (?) the Norchard Broadband is so flaky that it frequently reboots 3 or 4 times within an hour.

Anyway. I’ve ripped the script apart and rewritten it from the ground up to be more flexible. I’ve beefed up the logging, and now if it encounters a temporary error it does nothing until the next time it runs (a minute later) – when it should sort itself out.

If you’re interested, you can grab it from here https://github.com/paulseward/yaddc

Dynamic DNS woes – resolved

Our Dynamic DNS provider http://dnsdynamic.org seems to be having problems at the moment, and our wonderful BT Broadband has decided it wants to change its IP address right at this moment.

The practical upshot is that we’ve been offline since about 2pm yesterday. I’m working on a fix.

Update: Yesterday I changed our dynamic dns provider to http://noip.com, and it looks like my changes propagated by around 10:30pm last night – so we’re back in business.