Hetzner is a German based server hosting provider. We have seen intermittent problems in routing traffic to them in recent days.
The problem we see is that we send traffic to Hetzner's routers via the LINX Internet Exchange, and traffic goes no further. We have opened a ticket with LINX and with Hetzner regarding this.
LINX say they have no reported problems with Hetzner.
We have heard that another UK ISP may be seeing similar problems with routing to Hetzner, but we've not been able to verify this ourselves.
The problem hasn't reoccurred, but we'll keep this post open for a week or so in case it comes back.
Issue reopened - we see routing problems again today (March 6th).
We've contacted Hetzner to further investigate this. It seems traffic leaving our network for Hetzner via either of our two LINX routers go no further. Traffic leaving Hetzner for our network also go via LINX and go no further.
Traffic is working again, at the moment...
There have been three occasions where we've had routing problems to/from Hetzner: Feb 9th, Feb 13th/14th, March 6th.
Whilst the latest routing problem resolved itself after about 30 minutes we are still in conversation with LINX and Hetzner regarding this.
This problem hasn't reoccurred, we'll close this post for now.