Fragmentation

[ѽ҉ᶬḳ℠]

Any SQM measures deployed? That what it caused it on my nodes until
disabled.

On 18/06/2019 17:32, Nigel Magnay wrote:
> Hi!
>
> I have successfully set up a wireguard connection, to a server hosted
> inside Microsoft Azure. Thankyou for this software, it's so much
> easier to configure than the alternatives.
>
>
> I have a small problem though, which I think I understand (but seems
> strange), but I'm not sure of the correct solution.
>
> I have routed all internet traffic over this connection; it works, I
> can successfully ping sites, and view some. I'm using IP masquerading
> at both ends to connect entire networks (I thus use the client as a
> gateway).
>
> However - some hosts do not respond - or, rather, there's a packet
> fragmentation issue.
>
> I can see with tcpdump on the server entries like this:
>
> 17:55:04.461804 IP 85.118.26.200.https > vpn1.60630: Flags [.], seq
> 1:1441, ack 518, win 30, length 1440
> 17:55:04.461849 IP vpn1 > 85.118.26.200 <http://85.118.26.200>: ICMP
> vpn1 unreachable - need to frag (mtu 1420), length 556
>
> Which I take to mean "we got a response, it's length is too big to fit
> in the vpn payload, please shorten".
>
> What happens though is nothing - it just keeps receiving over-long
> responses, so it doesn't work - which is hardly wireguard's fault.
>
> Now, I guess either the end server is simply ignoring me, or the ICMP
> stuff is being blocked somewhere. I'm not knowledgeable enough to know
> if either of these are likely, as I'm a bit puzzle as to how anything
> could work properly if either of those were true.
>
> So - am I doing something wrong? What's the right knobs for me to be
> twiddling here?
>
> I have wireguard 0.0.20190601 at each end.
>
>
> _______________________________________________
> WireGuard mailing list
> WireGuard at lists.zx2c4.com
> https://lists.zx2c4.com/mailman/listinfo/wireguard