When I try a SSH connection to a 2862 router from various Linux versions, I get the error
"Unable to negotiate with 192.168.0.1 port 22: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1,diffie-hellman-group14-sha1"

I guess this is because of the security associated with the key method offered.  

Is it possible to upgrade the key method used on the router?

Hi John,

Try:

ssh -o KexAlgorithms=+diffie-hellman-group1-sha1 -o HostKeyAlgorithms=+ssh-dss username@routerip

It will warn you about the DSA fingerprint. Say yes to continue and it will add that host to its list.

At this point it may just pause, forever, so ‘Ctrl+C’ it, to cancel the connection attempt and arrow-up to recall your last command and execute it again, this time it should connect straight away and ask you for the password.

Thanks for your reply

I'd tried that, but it didn't work either on both Debian and Apple.

Unsupported KEX algorithm "diffie-hellman-group1-shal"
command-line line 0: Bad SSH2 KexAlgorithms '+diffie-hellman-group1-shal'.

Sorry!

It was a typo, I have corrected the typo, try again…

That worked! Thanks.