I think we found the issue. Looks like a pmtu issue with our upstream provider and their connection to the microsoft fabric. Working with them now. Thank you everyone for helping. Some reached me off list to help. John On Fri, Jun 28, 2024 at 10:31 PM Lincoln Dale <ltd@interlink.com.au> wrote:
Presumably nothing stops you spinning up an instance in Azure and doing pings/traceroutes yourself. But perhaps you could be doing this from your own IPs towards <whomever>.
Have you configured your end in a manner that doesn't do MTU 1500 or that relies on PMTUD to function? If yes, well perhaps start there... you're not on a solid foundation.
On Sat, Jun 29, 2024 at 7:46 AM John Alcock <john@alcock.org> wrote:
I have gotten pretty close to figuring out my issue with the Azure Cloud. When I advertise my routes through one specific upstream provider, I have an issue. If I pull my routes from them, all works well.
I believe this is some type of MTU issue. Could be filtering, but I doubt it.
Is there an Azure Looking glass that I can use to originate pings and traceroutes? My googlefu is weak and I haven't found it yet.
With that information, I think I can help my upstream provider know where the problem lies.
John Acock AS395437