I know -- catching up on old e-mail...
On Fri, Sep 05, 2003 at 10:18:45AM +0200, Iljitsch van Beijnum wrote:
Note that the next hop points to an address that falls within the (old) AMS-IX peering LAN prefix. Since this router isn't directly connected to the AMS-IX, it needs to resolve this next hop:
Two ways to remedy this:
- use next-hop-self on all iBGP peerings (which isn't always the perfect choice, but will easily fix these issues)
- filter the exchange prefix(es) for all IXes that you participate *and all more specifics* on *all* eBGP sessions. This is strongly recommended even when already using next-hop-self (more specifics can break eBGP sessions at the IXP peering routers)
A third and additional defensive measure could be to adjust the preference of your IGP to a value below that for eBGP, and do the moral equivalent of "redistribute connected" on the exchange point router into your IGP. Regards, - HÃ¥vard