OK, I'll see if I can do anything with it.

Can be either when idle or in the middle of a transfer. The main problem with this behaviour is that it takes so long to reconnect and reauthenticate.

I'm beginning to think there may be two separate issues:
- SFTP being slow over our internet link
- issues with recovering from connection outages

Is the connection dropped in the middle of transfer or when WinSCP is idle?

I'm not sure whether the problems I'm having are due to the SFTP protocol or are in WinSCP, maybe someone can let me know.

My link to the internet is via a satellite (VSAT) connection. Our local network (which I have no control over) is congested, largely due to virus/trojan infestation. This causes frequent short interruptions to internet access (usually a couple of seconds every few minutes).

Most applications seem to handle this fairly well, just taking longer to do whatever they do. WinSCP, however, seems to have more serious problems with these outages. Transfers are always really slow (much slower than plain FTP) and most of the time interruptions seem to kill off a transfer, requiring a reconnect.

Is SFTP especially sensitive to interruptions? Is there something I can change in the configuration that will make uploading files less painful?