SSH client not reading correct Host config

ilesterg · 06-14-2016, 03:39 AM

Hi,

My .ssh/config file looks like this:

Code:

Host *
  User user1
  IdentityFile /root/home/user1/id_rsa

Host host2
  Hostname host2.domain.com
  User user2

The problem is, when I do

Code:

ssh host2

it is asking for the passphrase for /root/home/user1/id_rsa. Why is that? I was expecting that the Host section to be read will be the 2nd one, in which case no private key is specified and thus should ask me for the user2 password.

Code:

-bash-3.2$ lsb_release -a
<cut>
Distributor ID: RedHatEnterpriseServer
Description:    Red Hat Enterprise Linux Server release 5.7 (Tikanga)
Release:        5.7
Codename:       Tikanga
-bash-3.2$ rpm -qa | grep ssh
openssh-4.3p2-72.el5_7.5
openssh-server-4.3p2-72.el5_7.5
openssh-clients-4.3p2-72.el5_7.5
sshpass-1.05-1.el5
-bash-3.2$ rpm -qi openssh-clients
Name        : openssh-clients              Relocations: (not relocatable)
Version     : 4.3p2                             Vendor: Red Hat, Inc.
Release     : 72.el5_7.5                    Build Date: Thu 18 Aug 2011 12:18:45 AM EDT
Install Date: Wed 26 Mar 2014 05:53:15 PM EDT      Build Host: x86-001.build.bos.redhat.com
Group       : Applications/Internet         Source RPM: openssh-4.3p2-72.el5_7.5.src.rpm
Size        : 862056                           License: BSD
Packager    : Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>
URL         : http://www.openssh.com/portable.html
Summary     : The OpenSSH client applications
Description :
OpenSSH is a free version of SSH (Secure SHell), a program for logging
into and executing commands on a remote machine. This package includes
the clients necessary to make encrypted connections to SSH servers.
You'll also need to install the openssh package on OpenSSH clients.

Thanks!

TenTenths · 06-14-2016, 03:54 AM

Quote:

Originally Posted by ilesterg

I was expecting that the Host section to be read will be the 2nd one, in which case no private key is specified and thus should ask me for the user2 password.

Why would you expect that?

Host * is the first match, so that will be used.

Change the order of your entries so that Host * is the last case.

ilesterg · 06-14-2016, 03:59 AM

I've seen a lot of examples online showing the * as the first entry. Tried putting the Host * at the bottom already, same output.

ilesterg · 06-14-2016, 04:03 AM

By the way, here's the output of ssh -vvv.

Code:

-bash-3.2$ ssh -vvv host2
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /root/home/thisuser/.ssh/config
debug1: Applying options for host2
debug1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to host2.domain.com [x.x.x.x] port 22.
debug1: Connection established.

TenTenths · 06-14-2016, 04:19 AM

My bad, brain fade on my part.

So what you're telling ssh is that for host2 to use:

Code:

  Hostname host2.domain.com
  User user2

and inherit

Code:

  IdentityFile /root/home/user1/id_rsa

Did you try:

Code:

Host host2
  Hostname host2.domain.com
  User user2
  IdentityFile ''

Habitual · 06-14-2016, 04:57 AM

Quote:

Originally Posted by ilesterg

Hi,

My .ssh/config file looks like this:

Code:

Host *
  User user1
  IdentityFile /root/home/user1/id_rsa

Is "My .ssh/config" the root user's .ssh/config?

Turbocapitalist · 06-14-2016, 05:10 AM

All the other host configuration will inherit the IdentityFile settings applied globally to Host *
And since IdentityFile can be used multiple times per host, adding another one won't overwrite or exclude the first. So with your current example configuration one way to do that is to do a negation.

Code:

Host * !host2
  User user1
  IdentityFile /root/home/user1/id_rsa

Host host2
  Hostname host2.domain.com
  User user2

Edit: but negation won't scale, for obvious reasons. It's better to make an inclusive pattern instead.