Issues with prefix / help needed

ic lists at
Sat Mar 25 08:54:50 UTC 2023

Hi there,

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 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. or

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 / 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?

BR, Michel

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