ssh사용 시 diffie-hellman-group1-sha1 관련

원문 : http://www.openssh.com/legacy.html

If the client and server are unable to agree on a mutual set of parameters then the connection will fail. OpenSSH (7.0 and greater) will produce an error message like this:

Unable to negotiate with legacyhost: no matching key exchange method found. Their offer: diffie-hellman-group1-sha1

For the case of the above error message, OpenSSH can be configured to enable the diffie-hellman-group1-sha1 key exchange algorithm (or any other that is disabled by default) using the KexAlgorithms option - either on the command-line:

ssh -oKexAlgorithms=+diffie-hellman-group1-sha1 user@legacyhost

or in the ~/.ssh/config file:

Host somehost.example.org  KexAlgorithms +diffie-hellman-group1-sha1

OpenSSH 7.0 이상에서는 해당 옵션이 기본으로 enable 되어 있지 않기 때문에

옵션을 넣어줘야 한다.

항상 넣기 귀찮으니 config를 만들어서 넣고 쓰도록 하자.

config파일이 없으면 그냥 생성하면 적용 됨.