I have a customer who is complaining about slow SFTP transfers over a long haul connection. The current transfer rate is limited by the TCP window size and the RTT. I looked at HPN-SSH, but that won't work because we don't control what software the peer is using. I was thinking about coding a much more modest enhancement that just does SO_RCVBUF for specific subsystems. In the interest of adding something that the OpenSSH community would take back into the source base, what do people think is a better fit in the configuration file? A single keyword for specifying connection options: SubsystemOptions <subsystem-name> [command-line-option...] The subsystem name would be scp, sftp-server, etc. The command line options would be -r <n> or --rcvbuf <n> to allow one to specify the number passed to SO_RCVBUF. This would allow one to easily add other options (like SO_SNDBUF support). An alternative would be to add the following option: SubsystemRcvbuf <subsystem-name> <n> This would be much easier to implement, but doesn't allow for more options to be added without another keyword. I guess this is the way I'm leaning, but I can be swayed. _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev
