Curious to know if they block Google’s DNS servers as well. That 1.x space was a RIPE research segment, so it’s possible that some internal AT&T group was using it with the assumption it would not be publicly routable and got bit. I was enjoying the shorthand ping of 1.1 for my router at home until Cloudflare took it over. Needless to say, if that was the case for AT&T, their ‘fix’ is not at all acceptable.