There have been reports of DNS problems for customers using 217.169.20.20 and 217.169.20.21. Customers may have seen error messages like 'Unknown host' in their programs.
For the past week we've been using new DNS resolvers in our new rack, but for the time being we've taken these offline and are using the original DNS servers whilst we investigate further.
The new servers have been taken off line, the new servers will come back when we're confident that they are working properly.