SSH-COPY-ID on AIX. SSH remote AIX’s box without password.

I’m sure most unix administrators knows the utility ‘ssh-copy-id’  part of OpenSSH. It’s very useful when we need to exchange SSH keys between hosts.
This simple shell script is available on most Linux distros, but it’s not available on AIX.  As ssh-copy-id is a simple script it will work on AIX as in Linux.

Here’s the code:

#!/bin/sh

# Shell script to install your public key on a remote machine
# Takes the remote machine name as an argument.
# Obviously, the remote machine must accept password authentication,
# or one of the other keys in your ssh-agent, for this to work.

ID_FILE="${HOME}/.ssh/id_rsa.pub"

if [ "-i" = "$1" ]; then
  shift
  # check if we have 2 parameters left, if so the first is the new ID file
  if [ -n "$2" ]; then
    if expr "$1" : ".*\.pub" > /dev/null ; then
      ID_FILE="$1"
    else
      ID_FILE="$1.pub"
    fi
    shift         # and this should leave $1 as the target name
  fi
else
  if [ x$SSH_AUTH_SOCK != x ] && ssh-add -L >/dev/null 2>&1; then
    GET_ID="$GET_ID ssh-add -L"
  fi
fi

if [ -z "`eval $GET_ID`" ] && [ -r "${ID_FILE}" ] ; then
  GET_ID="cat \"${ID_FILE}\""
fi

if [ -z "`eval $GET_ID`" ]; then
  echo "$0: ERROR: No identities found" >&2
  exit 1
fi

if [ "$#" -lt 1 ] || [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  echo "Usage: $0 [-i [identity_file]] [user@]machine" >&2
  exit 1
fi

# strip any trailing colon
host=`echo $1 | sed 's/:$//'`

{ eval "$GET_ID" ; } | ssh $host "umask 077; test -d ~/.ssh || mkdir ~/.ssh ; cat >> ~/.ssh/authorized_keys" || exit 1

cat <<EOF
Now try logging into the machine, with "ssh '$host'", and check in:

  ~/.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

EOF

Let’s modify permissions:

[root@lpar:/] chmod 755 ssh-copy-id

Generate SSHs keys for the user, using ssh-keygen command:

[root@lpar:/] ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/user/.ssh/id_rsa):
Created directory '/home/user/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/user/.ssh/id_rsa.
Your public key has been saved in /home/user/.ssh/id_rsa.pub.
The key fingerprint is:
37:f9:e6:67:23:17:eb:ad:d1:03:21:35:3d:34:38:56 user@lpar
The key's randomart image is:
+--[ RSA 2048]----+
|             o=E |
|            .+.o.|
|           .... .|
|           .. .  |
|        S +  .   |
|         . o  o. |
|            o .+.|
|           o. *o.|
|            .*oo.|
+-----------------+

Before execute ssh-copy-id, we need to know the syntaxis. The next bellowed is run only the first time, because it will create authorized_keys file on the remote side.

[user@lpar:/] ssh-copy-id remoteuser@remoteserver

Let’s see with an example.

We’ll set SSH Keys from user@lpar to user@remoteserver.

[user@lpar:/home/user] ./ssh-copy-id user@remoteserver
The authenticity of host 'remoteserver (172.17.32.102)' can't be established.
RSA key fingerprint is 8f:81:b7:3c:21:14:37:33:d3:af:9a:45:05:f9:73:a1.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'remoteserver,172.17.32.102' (RSA) to the list of known hosts.
user@remoteserver's password:
Now try logging into the machine, with "ssh 'user@remoteserver'", and check in:

  ~/.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.
[user@lpar:/home/user]

Once it has finished, we can verify we can ssh the remote user without prompt password. See:

[user@lpar:/home/user] ssh user@remoteserver
*******************************************************************************
*                                                                             *
*  Welcome to remoteserver!                                                   *
*                                                                             *
*******************************************************************************
Last unsuccessful login: Fri Sep  9 11:33:00 DFT 2011 on ssh from 172.21.10.78
Last login: Mon Nov 17 16:46:06 NFT 2014 on ssh from 172.16.32.104

[YOU HAVE NEW MAIL]
():[user] /home/user ->

That’s it!!

Just thanks if the post was helpful 🙂

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About igalvarez

More than 20 years experiences on IT industry. 20+ years in Unix experience : IBM-AIX, HMC/SDMC/IVM, SVC, Protectier, PureFlex Systems, VIOservers, IBM Bladecenters, IBM System Power, RedHat Linux, SuSE Linux, Debian/Ubuntu Linux. Solaris, SCO Unix, Tru64 Unix, Linux Virtualization: XEN, KVM, databases sb2, oracle, postgreSQL, Find more information here: http://en.gravatar.com/igalvarez
This entry was posted in AIX, SSH and tagged , . Bookmark the permalink.

4 Responses to SSH-COPY-ID on AIX. SSH remote AIX’s box without password.

  1. Sanat says:

    Thanks for the post. It solved my problem.

    Like

  2. Antonio says:

    Thanks you. very usefull.

    Like

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