So, in my previous entry, one of the things I mentioned was around putting static web content on a separate subdomain. Having done this myself, I created a subdomain for this site to serve up CSS and JS content and called it res.growse.com. It seems that this has been causing problems over the past few weeks with my secondary DNS providers.
If you care or understand about such things, read on. If not, the end point is that I think I’ve fixed it, but bear with me.
I use Everydns.com as my secondary DNS people. They’re wonderful. More importantly, they’re free. However, for the past few weeks, they’ve been serving up NXDOMAIN responses to DNS requests for res.growse.com. I spent a while troubleshooting this, only to find out that the IP address that they request zone transfers on a regular basis is different to the IP address they use to do the initial transfer. I could delete and then add my domain on their site, and watch in my log the initial transfer succeed, because that IP address was permitted. What I didn’t know was that future requests come in on a different IP, so they were being denied. This change seems to have happened back in March, if this tweet is anything to go by.
Everydns.com doesn’t have anything on their site about this change though. In fact, in their FAQ, under “What IP does everydns.net use to request my zone?”, 18.104.22.168 isn’t listed.
So there it is. If you use them, keep an eye on your AXFR requests and make sure they’re not failing. Or just allow anyone to transfer your zone, if you don’t care who has it.