ssh conections

OpenSSH is particular with how keys are stored and used. Do the following:

1) Create and ensure your ~/.ssh directory has the correct permissions:

$ mkdir ~/.ssh
$ chmod 700 ~/.ssh
$ ls -ld ~/.ssh
drwx------ 2 username group 4096 Jun 10 19:47 /Users/username/.ssh
2) Copy the private key (in your case the .pem file) to the ~/.ssh directory and set the appropriate permissions:

$ cp ~/Downloads/filename.pem ~/.ssh/filename.pem
$ chmod 600 ~/.ssh/filename.pem
3) Since you are using OS X make sure Finder didn't set any unnecessary extended attributes and remove them:

$ xattr -l ~/.ssh/filename.pem
$ xattr -d <attr_name> ~/.ssh/filename.pem
4) Now you can try using the key:

$ ssh -i ~/.ssh/filename.pem username@remote.hostname.com
5) Once you have verified this work you can use the ~/.ssh/config file to make connecting to the remote host easier, rather than having to manually specify the identity file to use. For example:

Host remote.hostname.com
  User username
  IdentityFile ~/.ssh/filename.pem
From this point forward you can just run ssh remote.hostname.com to connect to your remote server.