I’m contacting you because after spending 2 days troubleshooting I can’t seem to find a solution to the following.
We (AS45021) bought/transffered the 86.104.228.0/24 prefix a few months back because we couldn’t wait longer on the RIPE waiting list.
Before you ask, yes, AS45021 is currently single homed, this will change in a week (it requires travelling a few hundred miles and I couldn’t do it before).
Since we started announcing this prefix, things have been spotty, at best. While it seems visible in all the looking glasses I tried, it spends sometimes hours, sometimes days, being unreachable (you can try for ex. 86.104.228.1 or 86.104.228.26).
I have full access (up to packet capture) on the AS and its upstream. When I ping one of the IPs from various ISPs, I see the ICMP Echo Request and Reply on the wire, going where it’s supposed to go, but it doesn’t reach the pinging host. Pinging any IP of the upstream (AS42275 / 85.208.69.0/24 in this location) works.
ROAs and RPKI seem fine to me.
I’m starting to suspect that maybe the previous user of the prefix is still announcing it somewhere and “shouting louder” than me. It seems when I clear sessions, it immediately works for a while, then stops.
Do you all have any idea what I should check / try next?
While the problem is occurring, pick some of the collector hosts from Collectors – Route Views and telnet
to them. This will drop you into a Cisco-like CLI where you can "show
ip bgp 86.104.228.0" and find out what the BGP path to your network is
from a bunch of points around the world.
This should help you identify the fault if the echo-request from
86.104.228.1 reaches the remote host but the echo reply from the
remote host doesn't make it back to 86.104.228.1.
When I ping one of the IPs from various ISPs, I see the
ICMP Echo Request and Reply on the wire, going where
it’s supposed to go, but it doesn’t reach the pinging host.
The echo-request reaches your host at 86.104.228.1 but the echo-reply
doesn't reach the pinging host? That sounds more like a packet
filtering problem than a BGP problem.
Try doing a traceroute to the remote pinging host from two sources:
86.104.228.1 and one of your ISP's IP addresses (get them to assign
you one if you don't have one). The difference between the two may
give you an idea where the filtering error is.