SoftEther VPN User Forum

Weird issue - we are running SoftEther with the SoftEther client on L2TP, all pretty standard. The server and client are behind NATs and I have opened 500 and 4500 on the server NAT.

I can connect fine - I can even surf around a machine on the server's side of the NAT. But as soon as I try to copy a large file off the server side to the client, it fails. I wrote a little test app and the call to ReadFile takes like 60 seconds to return an error. If I look at the status on the server or the client - the data numbers are moving.

Even weirder - it WORKS if I copy the other direction. That is, if I copy to the other machine, everything works great! If I connect via Windows PPTP, everything works in both directions fine.

Client is Windows 8.
Server is Linux.
Server side machines are all Windows 8.
All the SoftEther versions are straight off the website yesterday.

L2TP is known to be brittle going through one NAT, so having it work through two NATs is fortunate.

First check the client_log and server_log for obvious errors. Past that, this kind of problem will be difficult to troubleshoot unless you can run something like wireshark on both sides of the L2TP session and have control of both gateway routers.

If you have SoftEther on both sides of the VPN connection, then running a native Cascade Connection across one UDP or TCP port would be a better solution than L2TP.

But if I am connecting using TCP directly to the listening port (with NAT-T turned off) - if the connection is made, then TCP can talk to each other, right? Isn't this the same thing network-wise as a native Cascade connection (TCP port connection)?

L2TP uses UDP.
SoftEther native client uses TCP.
These are different.

thisjun wrote:
> L2TP uses UDP.
> SoftEther native client uses TCP.
> These are different.

Right, I am connecting with the SoftEther native client with TCP. That's what isn't working. I can see directories on the other side of the link, but copying any large files fails.

This fails with multiple client machines connecting to multiple servers on the other end. This fails if I connect NET1->NET2, or if I flip it around and connect NET2->NET1. Connecting with plain old PPTP works fine for everything.

Again, small amounts of traffic works, large amounts immediately fails.

Any ideas? This hasn't

Did you check a server log?

Yes, nothing in there out of the ordinary. If you read through the posts on this board, there are lots of people with this same problem. SMB just doesn't work over SoftEther...

Do you use SecureNAT or localbridge?

Localbridge.

This doesn't work on *any* Windows client configuration - it's very easy to test, just try it.

(Workmachine)<-Linux or Windows VPN server<-Internet->(Homemachine)
Fails when copying files from/to work machine from/to home machine

(Workmachine)<-Linux or Windows VPN server<-Internet->Home VPN server->(Homemachine)
Fails when copying files from/to work machine from/to home machine

No SecureNAT, no UDP. Plain old softether server with softether clients. Nothing fancy at all. Literally, the very simplest VPN server. It connects, but copy any size files and it will immediately fail.

There are tons of posts like this when you scroll through and read everything. It should be trivial to reproduce...

First you talk about L2TP clients and then Softether clients.
In the latter case everything works fine here, SE server on Linux, SE clients on windows.
File copying works either way.

> First you talk about L2TP clients and then Softether clients.

Yes, imagine that - I am trying everything. So crazy, right?

I am glad your setup is working - but that doesn't really help me, or the (...hold on...) *7* other people describing the same or similar problems in the just first two pages of posts.

I even experimented with L2TP in the past. It worked, but was inherently slower in file copying.
The way to start is with a SE VPN server on one side and SE VPN clients on the other side.
If file copying is still a problem, I would look for the problem elsewhere.
Try to trace the SMB connections with MS network monitor or Wireshark.
Study you're server logs on times the file copy breaks down.

Sigh.

It is not slower in file copying. The file copying fails. It times out after 30 seconds and crashes inside the Win32 ReadFile call.

> The way to start is with a SE VPN server on one side and SE VPN clients on the other side.

That's all I'm doing. I set it up it *exactly* that way on four different links to different computers and different clients (SoftEther may not work, but it is incredibly easy to setup). All fail. All of them fail the same way the other people are describing on this forum. It is instantly repeatable with Windows 7 or Windows 8 clients.

> Study you're server logs on times the file copy breaks down.

As I said, there is nothing in the logs on the server or the client.

> Try to trace the SMB connections with MS network monitor or Wireshark.

Or just use a product that works.

Here
http://pastebin.com/raw.php?i=DA7XrcKa
you can see a network trace of a 2Mb file copy over SE client/server.
I do not have W8 machines on server side, only W7.
I can perform a test from a W8 client if you want to.

I'm not doubting your's works - that's just doesn't help those of us for whom it doesn't!

2MB tends to work for me as well, btw - that's not even 300 ms on our links. Mine fails on 1 GB file, but I suspect it's anything with sustained high-speed traffic. But your setup is just different enough not to matter...

I saw only 1 recent post where somebody had same problems.
For him it helped to turn off UDP acceleration (SE client/advanced options).
I will try to copy a 1Gb file from W7 to W8 and back.
My SE server runs on a raspberry (debian wheezy) and is not superfast.

[edit]
Copied a file back and forward W7 <-> W8.1 of size 1Gb with no problems
At speeds about 400 Kbs it took about 20 mins.
[/edit]

Please try to use another protocol to copy files like as HTTP, FTP etc.

Please try to use another protocol to copy files like as HTTP, FTP etc.

@thisjun : please explain why copy over VPN should not be used if both sides have a reliable internet connection ?

I don't know why transfer failed.
However, CIFS is not efficient in high latency network generally.

I don't know why transfer failed.
However, CIFS is not efficient in high latency network generally.