Hi Andy, Verio says they accept old class-a space at the /22 orshorter level so that isn't it. I am fairly certain you can not successfully multihome with PA class-A space.. If you are not announcing that /22 to AT&T then anyone that is single-homed to AT&T (or preferring them) will probably not be able to reach your /22. I ran into this problem with some 4/8 space that Level3 assigned to me by mistake. So you are dealing with more of a Policy issue rather than general prefix filter.
-Scott ----- Original Message ----- From: "Andy Ellifson" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, October 15, 2003 6:28 PM Subject: Re: Pitfalls of annoucing /24s > > I have a /24 allocated to my by XO Communications in Phoenix, AZ > (67.X.X.0/24). I am currently announcing it to Verio in Europe. A > friend of mine that is an XO customer in Phoenix with BGP to XO can get > to that address block within XO's network. > > But on the flip side. I also have a /22 from AT&T (12.X.X.0/22). When > I announce that network block to Verio in Europe (and nowhere else), > only certain places get to the Europe location. Networks that prefer > AT&T go to AT&T's network and die since the route isn't there. I don't > know if I am missing something but it think it may have to do with how > the network's peering/filter schemes work. > > I may just be walking around the problem since I am a transit customer > of Verio and they normally filter. > > -Andy > > > > --- Phil Rosenthal <[EMAIL PROTECTED]> wrote: > > > > On Oct 15, 2003, at 5:24 PM, H. Michael Smith, Jr. wrote: > > > > > > > > > > > What about the /24's that many ISPs (especially tier 2-3) are > > assigning > > > to multi-homed customers? What about an IX or "critical > > infrastructure > > > providers" that may be issued a /24 from ARIN (Policy 2001-3)? > > > > > As long as it's provider assigned, and your provider announces the > > supernet that the /24 is from, it will still work. If you announce > > PI > > space out of the old class A space in /24's, many networks wont be > > able > > to reach you. > > > > >
