RE: The use of .0/.255 addresses.

I see traffic from this last IP address octet all the time from prefixes of length less than /24. Use of these host id's when the prefix length is greater than or equal to /24 is illegal. So if that's your case, I'd suggest not doing it. If that's not the case, look for over-zealous or incorrect filters in the path. I saw this situation once before. There was a border ingress filter with a typo in it... Chris

Various people I've asked about this have said they wouldn't use the .0 or .255 addresses themselves, though couldn't present any concrete info about why not; my experience above would seem to suggest a reason not to use them.