We have a remote office with just two staff, who rely on a 3G internet connection for their basic internet needs (email and web browsing). They only get around 4 Mbps down and 1.5 Mbps up, but this is fine as they use Outlook more than anything else (and we have no other affordable alternatives in this remote location).
In order to access files on the Windows server at our main office, we have a VPN client installed on both users' PCs. This used to be LogMeIn Hamachi (which worked well) but, when LogMeIn ceased to be free, we switched from Hamachi to a free alternative called SoftEther VPN.
Here's the interesting part:
SoftEther VPN works perfectly when our staff try to access the server using their personal computers from home (i.e. over regular broadband internet) but, when at the remote site and using the 3G internet connection, they are only able to browse the folder structure on the server. As soon as they try to either copy or move a file (even a tiny 20 KB Word document) from the server (which is at the main office with broadband) to their PC (over the cellular 3G connection), it always fails.
When I ran a speed test (speedtest.net) at the remote site, I get the following:
Ping: 90 ms
Download: 4 Mbps
Upload: 1.5 Mbps
We can't move files using our VPN client but, if those same files are uploaded to Dropbox and we open them using the web interface, they open instantly. So, it's not as though this 3G internet connection has problems in general.
The failed file transfers only occur when using this particular VPN client (it was fine with Hamachi but stopped working with SoftEther VPN) with this particular internet connection (SoftEther VPN works fine for users working from home, using regular broadband, but not at this one office with 3G internet).
Any ideas what could be going on here?
