If you want to be done with the headaches forever, never to ever have to worry or contend with this again, append this to the end of your /etc/ssh/ssh_config file:
Ciphers 3des-cbc,aes128-cbc,aes192-cbc,aes256-cbc,aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected],[email protected]
MACs hmac-sha1,hmac-sha1-96,hmac-sha2-256,hmac-sha2-512,hmac-md5,hmac-md5-96,[email protected],[email protected],[email protected],[email protected],[email protected],hma[email protected],[email protected],[email protected],[email protected],[email protected]
HostKeyAlgorithms ssh-ed25519,[email protected],[email protected],[email protected],ssh-rsa,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected]
KexAlgorithms diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,curve25519-sha256,[email protected],[email protected]
This comes with the usual warnings from others here... Whaaa the sky is falling you so insecure. Whaaa.... To such people, I say keep your negativity and unhelpful comments to yourself. We're all professionals here. We know what the risks are of using deprecated ciphers and key exchanges. Sometimes there are use cases, like accessing end-of-life or old systems.
BTW, the above can be limited to specific hosts if desired. Not a bad idea, but that is up to you. What you do with the power and capability gained from the above is now your responsibility to exercise judiciously.
Unable to negotiate with 192.168.1.1 port 22: no matching key exchange method found. Their offer: curve25519-sha256,[email protected],ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,[email protected]
so I added the first offer into config and it worked