I have a pending change to stop using class A/B/C netmasks when setting an interface address without an explicit mask, and instead to use a default mask (24 bits). A question has arisen as to what the default mask should be for loopback interfaces. The standard 127.0.0.1 is added with an 8 bit mask currently, but additions without a mask would default to 24 bits. There is no warning for missing masks for loopback in the current code. I'm not convinced that the mask has any meaning here; only a host route to the assigned address is created. Does anyone know of any meaning or use of the mask on a loopback address?
Thanks, Mike