do not check host key
ssh -o StrictHostKeyChecking=no user@ssh-server
.ssh/config
settings for all hosts with DSA
PubkeyAcceptedKeyTypes=+ssh-dss
KexAlgorithms +diffie-hellman-group1-sha1
https://www.mostlynetworks.com/2016/10/fixing-macos-sierraopenssh-7-x-compatibility/