But in such a case, when we share a public key from server/system B to server/system A, this generally indicates that user from server B is transferring files to server A and not vice-versa.
No! It means that the authentication is done in this direction.
Consider it this way: if you give someone the key to your house he has access to it. That could mean he takes away something or brings something, but this difference is not depending on him receiving your key or not. He could do both these things without the key too, he just would have to ring your bell (and wait till you answer it) if he lacks the key.
If userA@systemA (notice that "userA" on one system and "userA" on another system are two different accounts, they just happen to share the same name) has his key on systemB this user is allowed to log on (without password). What he does after this logon is not determined by the key at all. He could put files (that is: transfer to the server) or get files (that is: copy files from that server).
This is also possible with classical ftp or sftp: there is the put/mput command to move files to the system and get/mget command to move/copy files from the system.
In scp this would look like:
This will transfer a remote file from "system" using the account "user" to the local system. The other way would be:
This would transfer a local file using the account "user" to the remote system "system". The difference between having put the key of your local user on "system" will be: without the key you need to authenticate, with the key you don't.
Hello.
I have got 3 unix boxes A B C. Box A is being used to prepare some reports. After the reports generation, Box A sftp the reports to Box B and Box C. When I look at the report in Box B and Box C. The reports are different. In Box B, I see using od -x command there is CRLF (\r\n) at the end... (7 Replies)
Hi,
I have this problem where sometimes my files would go missing when I schedule my crontab to run the SCP command to get file from the SFTP server.
My crontab will run the scripts at an interval of 3 minutes (between the two scripts) The following is the setting in my crontab.
... (1 Reply)
Dear Unix Gurus,
I have a question to confirm before I proceed to script my program.
I'm currently running on IBM AIX Ver 5.3.
I just like to know if it's compatible to use scp or sftp between AIX and Wintel server?
I'm trying to scp or sftp a file from AIX to Window server and I was... (1 Reply)
Hi Frdz
I have a problem like.
I need to transfer a file from source to destination (different systems with different IPs) using "scp" command and before transfer the file i have to check the file is available in destination or not, if it is there no need to transfer, otherwise we have to... (5 Replies)
I have a shell script which uses SCP command to transfer the files from one server to another server. The files are getting transferred successfully, but the problem is the files transferred to the destination server didnot have the permissions as that of the files on the source server.
Command... (5 Replies)
Hello,
i have to write a script to perform sftp from the remote server to another server.
the files which are at the remote location are huge data log files which should be transfered to my server in a particular folder.
could you please provide me the general code (simple )... (1 Reply)
HI
I need to write a script in 415univ server which should go to 534unix server and move the files from there to windows server.
I am not able to get it bcoz sftp prompt is not allowing ftp command.
Can some one plz help me
Thanks in advance (3 Replies)
I have 3 AIX server namely - Server 1 , Server 2 and Server 3.
And have done SCP setup between Server 1 and Server 2 so that i dont have to give password when i transfer file from Server 1 to Server 2 by setting public key between the server.
Q1. If the unix password of the target server... (3 Replies)
On unix AIX server, when I am trying to transfer file from one directory to another directory on the same server through a program(where i call the script) it gives error "Lost Connection". (5 Replies)
Discussion started by: Pash
5 Replies
LEARN ABOUT CENTOS
ssh-copy-id
SSH-COPY-ID(1) BSD General Commands Manual SSH-COPY-ID(1)NAME
ssh-copy-id -- use locally available keys to authorise logins on a remote machine
SYNOPSIS
ssh-copy-id [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
ssh-copy-id -h | -?
DESCRIPTION
ssh-copy-id is a script that uses ssh(1) to log into a remote machine (presumably using a login password, so password authentication should
be enabled, unless you've done some clever use of multiple identities). It assembles a list of one or more fingerprints (as described below)
and tries to log in with each key, to see if any of them are already installed (of course, if you are not using ssh-agent(1) this may result
in you being repeatedly prompted for pass-phrases). It then assembles a list of those that failed to log in, and using ssh, enables logins
with those keys on the remote server. By default it adds the keys by appending them to the remote user's ~/.ssh/authorized_keys (creating
the file, and directory, if necessary). It is also capable of detecting if the remote system is a NetScreen, and using its 'set ssh pka-dsa
key ...' command instead.
The options are as follows:
-i identity_file
Use only the key(s) contained in identity_file (rather than looking for identities via ssh-add(1) or in the default_ID_file). If the
filename does not end in .pub this is added. If the filename is omitted, the default_ID_file is used.
Note that this can be used to ensure that the keys copied have the comment one prefers and/or extra options applied, by ensuring that
the key file has these set as preferred before the copy is attempted.
-n do a dry-run. Instead of installing keys on the remote system simply prints the key(s) that would have been installed.
-h, -? Print Usage summary
-p port, -o ssh_option
These two options are simply passed through untouched, along with their argument, to allow one to set the port or other ssh(1)
options, respectively.
Rather than specifying these as command line options, it is often better to use (per-host) settings in ssh(1)'s configuration file:
ssh_config(5).
Default behaviour without -i, is to check if 'ssh-add -L' provides any output, and if so those keys are used. Note that this results in the
comment on the key being the filename that was given to ssh-add(1) when the key was loaded into your ssh-agent(1) rather than the comment
contained in that file, which is a bit of a shame. Otherwise, if ssh-add(1) provides no keys contents of the default_ID_file will be used.
The default_ID_file is the most recent file that matches: ~/.ssh/id*.pub, (excluding those that match ~/.ssh/*-cert.pub) so if you create a
key that is not the one you want ssh-copy-id to use, just use touch(1) on your preferred key's .pub file to reinstate it as the most recent.
EXAMPLES
If you have already installed keys from one system on a lot of remote hosts, and you then create a new key, on a new client machine, say, it
can be difficult to keep track of which systems on which you've installed the new key. One way of dealing with this is to load both the new
key and old key(s) into your ssh-agent(1). Load the new key first, without the -c option, then load one or more old keys into the agent,
possibly by ssh-ing to the client machine that has that old key, using the -A option to allow agent forwarding:
user@newclient$ ssh-add
user@newclient$ ssh -A old.client
user@oldl$ ssh-add -c
... prompt for pass-phrase ...
user@old$ logoff
user@newclient$ ssh someserver
now, if the new key is installed on the server, you'll be allowed in unprompted, whereas if you only have the old key(s) enabled, you'll be
asked for confirmation, which is your cue to log back out and run
user@newclient$ ssh-copy-id -i someserver
The reason you might want to specify the -i option in this case is to ensure that the comment on the installed key is the one from the .pub
file, rather than just the filename that was loaded into you agent. It also ensures that only the id you intended is installed, rather than
all the keys that you have in your ssh-agent(1). Of course, you can specify another id, or use the contents of the ssh-agent(1) as you pre-
fer.
Having mentioned ssh-add(1)'s -c option, you might consider using this whenever using agent forwarding to avoid your key being hijacked, but
it is much better to instead use ssh(1)'s ProxyCommand and -W option, to bounce through remote servers while always doing direct end-to-end
authentication. This way the middle hop(s) don't get access to your ssh-agent(1). A web search for 'ssh proxycommand nc' should prove
enlightening (N.B. the modern approach is to use the -W option, rather than nc(1)).
ENVIRONMENT
SSH_COPY_ID_LEGACY
If the SSH_COPY_ID_LEGACY environment variable is set, the ssh-copy-id is run in a legacy mode. In this mode, the ssh-copy-id doesn't
check an existence of a private key and doesn't do remote checks of the remote server versions or if public keys are already
installed.
SEE ALSO ssh(1), ssh-agent(1), sshd(8)BSD June 17, 2010 BSD