The Problem
About a month ago I began to notice that I could not reach Tumblr websites that use a custom domain name1. This became a problem when I decided to move the blog portion of Quantum Pie over to Tumblr and host it on my subdomain blog.quantumpie.com. Not being able to access your own blog from home sucks.
After doing some digging, I came across this informative post by the bảohouse about how to make a Tumblr custom domain more robust. All Tumblr domain names, by default, are routed through a server that is hosted by Rackspace. This is the 72.32.231.8. IP address that Tumblr tells you to point to when setting up a custom domain name. For some reason I could not reach this server from home.
The Solution
There are other servers that Tumblr uses to deal with custom domain names, but it does not publish these publicly. The trick is to let the internet know that these other servers can be used to find your custom domain.
To do this you must create additional A records in your DNS settings that point to your site. Just repeat the standard Tumblr instructions for setting up a custom domain name to create an A record for each of the following IP addresses:
- 50.22.53.155
- 50.22.53.157
- 72.32.231.8 (the default Tumblr IP address)
- 174.121.98.156
- 174.121.66.230
It may take a few hours for the changes to take effect.
If you use a custom domain name with Tumblr, you should add these extra records. It will increase the robustness of your website.