Add two-factor authentication to your ssh in 30 seconds. (blog.authy.com)

So what if the site goes down?

I can't ssh since force command is failing?

Can anyone tell me if that's really worth it? Looks like a bit of an overkill considering the protection given by ssh keys.

Does it works just with SMS?

I've used the libpam module for Google Authenticator[0] before, the difference being that it isn't dependant on the availability of a third-party service, but you have to be much more careful about losing your device. That said Authy do have pretty great uptime[1]

Nice for production servers, but becomes a an annoyance after the cool factor wears off for servers that don't really need it :) Installable on aptitude using libpam-google-authenticator (guide [2]).

[0]: https://code.google.com/p/google-authenticator/ [1]: http://status.authy.com/ [2]: https://scottlinux.com/2013/06/02/use-google-authenticator-f...

I looked at the site for some time and couldn't find an answer to my question. Does anybody know if the SMS is just for US cellphones?