Issues with prefix / help needed

William Herrin bill at
Sat Mar 25 10:05:25 UTC 2023

On Sat, Mar 25, 2023 at 1:54 AM ic <lists at> wrote:
> Do you all have any idea what I should check / try next?

A good tool for diagnosing BGP problems is:

While the problem is occurring, pick some of the collector hosts from and telnet
to them. This will drop you into a Cisco-like CLI where you can "show
ip bgp" 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 reaches the remote host but the echo reply from the
remote host doesn't make it back to

> 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 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: 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.

Bill Herrin

For hire.

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