linux下SSH无密码登录

把windows下的.ppk文件转成linux下的openssh key（实现无密码登录）:

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Do it with Putty.

• Linux: with your package manager look for the putty alternative:

  • Debian like apt-cache search putty
  • RPM based yum list putty
  • Gentoo emerge --search putty
  • etc.

• OS X: Install Homebrew, then run brew install putty

Place your keys in some directory, e.g. your home folder. Now convert the PPK keys to SSH keypairs:

cd ~
puttygen id_dsa.ppk -O private-openssh -o id_dsa

for the private key, and

puttygen id_dsa.ppk -O public-openssh -o id_dsa.pub

or the public key. Move these keys to ~/.ssh and make sure the permissions are set to private for your private key:

mkdir -p ~/.ssh
mv -i ~/id_dsa ~/.ssh
mv -i ~/id_dsa.pub ~/.ssh
chmod 600 ~/.ssh id_dsa

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参考：http://superuser.com/questions/232362/how-to-convert-ppk-key-to-openssh-key-under-linux

多个server key的解决办法（config文件）

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Pointing to the Key

The only problem now, is that when ssh searches for a key, it won’t be able to find the one it’s looking for. You need to correctly edit your config file that should be located in your ~/.ssh/ folder. If it isn’t already there, just create a new file.

Mine looks like the following:

Host github.com User git Hostname github.com PreferredAuthentications publickey IdentityFile ~/.ssh/git/id_rsa Host fedoraproject.org Hostname fedoraproject.org PreferredAuthentications publickey IdentityFile ~/.ssh/fedoraproject/id_rsa Host fedorapeople.org Hostname fedorapeople.org PreferredAuthentications publickey IdentityFile ~/.ssh/fedoraproject/id_rsa

It’s fairly self-explanatory what each part of the file is, you could even just use mine as a template.

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参考：http://www.robotgoblin.co.uk/blog/2012/07/24/managing-multiple-ssh-keys/

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UPDATE:

遇到的问题：config里Host项可以写域名，也可以写IP,但是，ssh 域名登录时，config的Host就必须是域名， ssh IP登录时， config的Host就必须是IP。