[rancid] As one door closes, another opens... ssh failing with (some) Cisco devices after OS upgrade?

[Randy Bush]

> There is an option you can pass to SSH ['-o 
> KexAlgorithms=diffie-hellman-group14-sha1'] to allow it to connect to 
> older versions of IOS. The error emitted by SSH isn't much help at all.

for really older images, e.g. those on a 2511, try

   ssh -1 <hostname>

randy