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
Article Number: 509
Posted: Thu, Feb 21, 2019 5:59 PM
Last Updated: Thu, Feb 21, 2019 5:59 PM
Online URL: http://kb.ictbanking.net/article.php?id=509