Well yes, there's a possibility to rate-limit NTP packets, but I don't think it would apply on all ISP (maybe they forgot to do it)
Ok, I am onboard; anything I can reference to get this done using openwrt?
What makes you believe that the fantasy solution you are creating by putting Wireguard into some kind of TCP tunnel would not have the same issues?
Mmmh, a quick search revealed:
But you will need to rent a server/VPS somewhere "in the cloud" to terminate your GRE tunnel...
Personally, I have no first hand experience with GRE (or wireguard) so I will not be of much help from here on....
GRE requires both endpoint IPs, expecting public addresses over the internet.
Also, a domain endpoint is not supported by netifd, so it may need custom scripts with DDNS.
Thus I'm afraid GRE is not suitable in this case, and other VPNs should fit better.
Yeah this is a bit annoying with Wireguard. I fully understand why, the TCP back off is not great with TCP connections running over a TCP tunnel. Sadly there is sometimes no choice, lots of people block UDP.
You can basically:
1/ Go hunting for open UDP ports NTP, DNS or Traceroute (also a good one). This is increasingly hard with more deep packet inspection (even light packet inspection can detect things like too much traffic over these). I have seen (increasingly) networks that just allow TCP port 80 and 443, and UDP 53 to only their local DNS server.
2/ Use udptunnel, no magic solution either. It doesn't look very HTTPS or HTTP to any deep packet inspection, so can be blocked easily, especially by state actors.
3/ For OpenVPN I have two servers, the UDP listener when allowed for good performance. And a TCP listener I connect via "stunnel" to. The stunnel wraps a TLS connection on top of the OpenVPN, so looks quite HTTPS to DPI. This pretty much always works for me.
But no option to do this with the UDP of Wireguard. And things are starting to get messy if you layer Wireguard -> udptunnel -> stunnel. It would be nice if stunnel were to offer a UDP option.
This is what stops me going full Wireguard. There are lots of places I need to use TCP VPN, so long as the network is stable it works pretty well, and maybe my only option.
I looked into UDPTunnel, for some reason it doesn't work in openwrt. GRE is an option, hopefully this forum will bring more attraction and other ideas.
Blocking UDP entirely would only disrupt important things such as DNS & NTP (for time sync).
So it makes sense if they (the ISP) won't interfere with that.
Instead of using TCP, why don't try to use UDP port 53 & UDP port 123?
I'm pretty sure it won't get blocked
Port 53 (DNS) worked fine for me, from a hotel with paranoid firewall settings.
That is not paranoid at all.
A firewall can easily intercept plain DNS and NTP.
And redirected it the local service as already mentioned above.
So this is not an option in general case.