Hoi Marc,
pim@sixxs.net here :)
On Mon, Jan 4, 2010 at 9:02 PM, Marc SCHAEFER schaefer@alphanet.ch wrote:
Hi,
It seems the Swiss POP for sixxs (IPv6 connectivity) is unreachable from Cablecom (net2000), Sunrise ADSL, Bluewin ADSL, but is reachable from Green ADSL.
It is unreachable for any ISP which does not peer with IP-Man at TIX or CIXP (or other exchanges like AMS-IX and SFINX). See below for rationale.
It used to be reachable in november 2009 when I did my last tests, on Cablecom (net2000). Does anyone has an idea why it is not routed correctly ?
I beg to differ an opinion: it is routed correctly. :)
Is this because it's a lone /24, and most providers don't peer correctly for less than /22 ? An administrative problem (like when EUnet was routed through Amsterdam for SWITCH customers -- well at least it was routed!)
It's not an administrative problem, it's a purposeful configuration.
Or is it because IP-MAN wants direct peering and doesn't announce the prefix globally ?
This is the reason - it is only announced to peers, not to transit providers. One obvious way to reach it is to start peering with IP-Man at one of the IXPs at which they are present. I, too, am a cablecom subscriber and I do not have access to the machines either from home - I have to hop over to another network first, one that peers with IP-Man.
Maybe to avoid being charged by strange peering plans ?
Well, it's to avoid being DDoSed to hell and back[tm]. There is an EFnet server (irc.efnet.ch) and an IRCnet server (ircnet.ipng.ch) and a well known tunnelbroker (chzrh01.sixxs.net) in that /24 - and all of them are packet magnets, unfortunately :(
PS: I am especially interested because I am considering to route a old /24 from a /15 (allocation unspecified) somehow, and want to see if it is really usually unfeasible from a global routing perspective, or from the practical quirks of commercial operators today.
I can confirm (as owner of that /24) that there was never a problem announcing it, and it used to be globally visible. Now, it is in a gray area, and purposefully not visible worldwide.
If you have a /24 you should be generally accepted by most every ISP out there, as far as breaking aggregation of your /15, I cannot comment (but I say: go for it)
groet, Pim