I will have to look through what settings Fastmail are using but this is a good starting of point. It's not from a "consumer" network IP block but I will look i

I will have to look through what settings Fastmail are using but this is a good starting of point. It's not from a "consumer" network IP block but I will look into the details that you have provided and see if it changes anything. Thanks a lot, always good to have a starting point.