Re: OpenVPN suddenly working one way only

From: Andrea Venturoli <ml_at_netfence.it>
Date: Mon, 08 Jul 2024 06:17:06 UTC
On 7/6/24 18:13, Patrick M. Hausen wrote:

Hello.


>> It's almost surely due to a problem with the UDP packets that implement the VPN: again, according to tcpdump they go out host B, but never reach host A.
> 
> Is it remotely possible that one of the ISPs blocks these UDP packets as part
> of an automatic "DoS protection" mechanism?

Of course I cannot exclude it with 100% confidence.

That said:
_ host A has about 10 VPNs, only one is misbehaving, so I guess it's not 
ISP A;
_ host B has an enterprise-grade contract, so they should not firewall 
anything; another one of the above VPNs connects to a different host 
which has the same type of contract with the same ISP and it works.

Maybe it's the ISP or someone in between... I have no control over this.
I'd like to exclude any local issue, about which I might actually do 
something.

  bye & Thanks
	av.