On the impossibility to use escape sequences when the networks hangs

[openssh at tr.id.au]

> > In short: how does one control an interactive connection that
> > currently is incapable to send/receive data? ssh just hangs.
> 
> 
> What happens if you try :
> 
> $ ssh -e\^ -l someusername remotehost
> 
> I use that sort of thing all the time. The manpage says :
> 
> -e escape_char
> Set the escape character for sessions with a pty (default: '~').
> The escape character is only recognized at the beginning of a
> line. ... <snip>

I believe it's easy to overlook/forget the requirement: "The escape character is only recognized at the beginning of a line."

I suppose using this sequence would solve the OP's issue: <Enter>~. (aka <Enter><Shift-Backtick><Period>)

Indeed, this should be processed client-side. I've never had a problem killing a hung connection once I remembered to always prefix the escape with a newline.

~ Tim