Bret Baptist wrote: [...]
Right now I have visi.com as one provider (AS8015), and Qwest (AS3908) as the other. When I look at the as-paths for my netblocks the ones from visi.com look fine, 208.42.20.0/23 and 208.42.104.0/23, the ones from Qwest go through visi.com and then on to us, 65.116.186.0/24, 65.121.8.0/23. The Qwest networks are the ones that I am having problems reaching hosts from or getting to from other networks. [...]
It's a bit of a long shot and difficult to see, but when I see natural C blocks without problems and natural A blocks with, I tend to suspect class-based filtering. This usually occurs if there's no less-specific route available, but there's 65.112.0.0/12 from Qwest covering both. This leaves only a few very obscure possibilities, so I wouldn't chase this except as a last resort. Peter E. Fry