Originally posted by: VirtualLarry
Originally posted by: bsobel
And now, with XP SP2, it's not doing that. Only a single IP within that block is allowed access.
The important part of that quote was "The third sentence, which says that 127.0.0.1 with a bitmask of 32 is the common implementation for loopback- a bitmask of 32 means that only 127.0.0.1 is loopback, not 127.0.0.x. The second sentence can be taken to imply that 127.x.x.x could all loopback, but the third says that this is not the ordinary implementation." Not saying MS shouldn't restore the previous functionality (doesn't appear it was intentionally removed), I was just commenting that I don't think the RFC is as clear as you suggested on the issue. The hotfix is available and that will migrate into a public fix after it gets regressed.
I was just trying to point out, that even as you quoted, the standard calls for the entire block of 127.x.x.x IPs to be considered the localhost loopback.
The fact that it also mentions that a common implementation only supports 127.0.0.1, doesn't make that the actual standard, IMHO, just an example. The actual standard reserves that entire IP range/block, and that fact is well-understood among networking people. The fact that otherwise legitimate and working networking apps broke because of MS's code changes also tends to support that.
A lot of RFCs are left intentionally vague so that implimentations can differ a bit. I'm guessing that the whole 127.0.0.0/8 range is used for loopback on Windows OSes, just that only 127.0.0.1 is implimented. I don't think I've seen an OS that sets up 127.0.0.2 or any other by default.
