Newer SSH clients such as on MacOS 10.14 (Mojave) may not want to use the old key sizes and cipher suites on an ASA.
One error message is about key exchange parameters:
no matching key exchange method found. Their offer: diffie-hellman-group1-sha1
Can fix this by using the older key exchange algorithm as an command line option:
ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 username@myasa.com
This can then be fixed server-side on the ASA by configuring Group 14 (2048-bit keys)
ASA(config)# ssh key-exchange group ? configure mode commands/options: dh-group1-sha1 Diffie-Hellman group 2 dh-group14-sha1 Diffie-Hellman group 14 ASA(config)# ssh key-exchange group dh-group14-sha1
Likewise may get messages about cipher suites not matching:
no matching cipher found. Their offer: aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc
Workaround is to specify ciphers as an option to SSH:
ssh -c aes128-cbc,3des-cbc username@myasa.com
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