It would be nice to have counterparts of ClearAllForwardings for SetEnv and SendEnv (probably independently for each). Consider a user uses those in his ssh_config, maybe to even forward sensitive data (whether that's smart is of course another topic). Now there may be programs that internally use a ssh connection for something, and which know already for sure that no Send/SetEnvs will be needed and they'd wish for a way to disable these. One might think at first that it works to simply do: -o SendEnv=-* but while that would remove a previously set (on the command line) -o SendEnv=foo it doesn't affect anything from ssh_config, as this is parsed later (which I think would be nice to have explicitly documented, again, I could provide a patch if it helps). A workaround for that is to use env and call e.g. env -i ssh ... Perhaps it would be nice to have something like -o SendEnv=!PATTERN which removes PATTERN permanently (i.e. cannot be re-added later). But there doesn't seem to be a way to generally (and permanently) remove any SetEnv set env vars. Thanks, Chris.