chmod 400 .pem

[jalal@csa2 ~]$ ssh -i Mona_hcomp.pem ubuntu@ec2-34-214-87-187.us-west-2.compute.amazonaws.com
The authenticity of host 'ec2-34-214-87-187.us-west-2.compute.amazonaws.com (34.214.87.187)' can't be established.
ECDSA key fingerprint is SHA256:o/4ids1iAbtK5xwDRECSYMpCs0HwGVHYQEvQFFz+Q0s.
ECDSA key fingerprint is MD5:12:e3:77:9f:85:f2:93:2e:be:a1:92:30:0d:e3:44:8b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'ec2-34-214-87-187.us-west-2.compute.amazonaws.com,34.214.87.187' (ECDSA) to the list of known hosts.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Permissions 0644 for 'Mona_hcomp.pem' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.
Load key "Mona_hcomp.pem": bad permissions
Permission denied (publickey).
[jalal@csa2 ~]$ chmod 400 Mona_hcomp.pem
[jalal@csa2 ~]$ ssh -i Mona_hcomp.pem ubuntu@ec2-34-214-87-187.us-west-2.compute.amazonaws.com
Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.13.0-74-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

  System information as of Fri Sep  1 22:01:33 UTC 2017

  System load:  0.0               Users logged in:                0
  Usage of /:   82.0% of 7.74GB   IP address for eth0:            172.31.43.224
  Memory usage: 9%                IP address for docker0:         172.17.0.1
  Swap usage:   0%                IP address for br-6549def12059: 172.18.0.1
  Processes:    138

  Graph this data and manage this system at:
    https://landscape.canonical.com/

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

280 packages can be updated.
207 updates are security updates.

New release '16.04.3 LTS' available.
Run 'do-release-upgrade' to upgrade to it.


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Last login: Fri Sep  1 22:01:33 2017 from dhcp-wifi-8021x-155-41-86-170.bu.edu