Issue with Net::SSH::Perl - can't establish connection

dayton has asked for the wisdom of the Perl Monks concerning the following question:

Using Net::SSH::Perl and I can't establish a connection even though my key is accepted... what am I missing?

.ssh/config:

	Host remote.ssh.server
    	ControlMaster auto
    	ControlPath ~/.ssh/master-%r@%h:%p
    	User myusername
    	IdentityFile id_rsa

The Code:

    $ssh = Net::SSH::Perl->new($host,debug=>true,options => ["ConnectT
+imeout=5","StrictHostKeyChecking=no"]);
    $ssh_conf="$ENV{'HOME'}/.ssh/config";
    $cfg = Net::SSH::Perl::Config->new($host);
    $cfg->read_config($ssh_conf);
    if (! $USERNAME){
        $USER=$cfg->get('user');
    }
    eval{$ssh->login($USER);};
       if ($@){
           print "Unable to connect to $host\n$@\n";
    }
    eval{($out, $err, $exit)=$ssh->cmd($exec_cmd);};print "Unable to e
+xecute: $exec_cmd\n" if $@;
  ###
  print "\n\nmade it this far\n\n";
  ###
    if ($out){
           print $out;
    } else {
        print "$err\n$exit";
    }
[download]

result:

local.host: Reading configuration data /home/myusername/.ssh/config
local.host: Reading configuration data /etc/ssh_config
local.host: Connecting to remote.ssh.server, port 22.
local.host: Remote version string: SSH-2.0-OpenSSH_7.2
local.host: Remote protocol version 2.0, remote software version OpenSSH_7.2
local.host: Net::SSH::Perl Version 2.09, protocol version 2.0.
local.host: No compat match: OpenSSH_7.2.
local.host: Connection established.
local.host: Sent key-exchange init (KEXINIT), waiting for response.
local.host: Using curve25519-sha256@libssh.org for key exchange
local.host: Host key algorithm: ssh-ed25519
local.host: Algorithms, c->s: chacha20-poly1305@openssh.com <implicit> none
local.host: Algorithms, s->c: chacha20-poly1305@openssh.com <implicit> none
local.host: Generating ephemeral key pair.
local.host: Entering Curve 25519 Key Exchange.
local.host: Sent client public key, waiting for reply.
local.host: Received host key, type 'ssh-ed25519'.
local.host: Host 'remote.ssh.server' is known and matches the host key.
local.host: Verifying server signature.
local.host: Send NEWKEYS.
local.host: Waiting for NEWKEYS message.
local.host: Enabling encryption/MAC/compression.
local.host: Sending request for user-authentication service.
local.host: SSH2_MSG_EXT_INFO received
local.host: SSH Extension activated: server-sig-algs=rsa-sha2-256,rsa-sha2-512
local.host: Service accepted: ssh-userauth.
local.host: Trying empty user-authentication request.
local.host: Authentication methods that can continue: publickey,gssapi-keyex,gssapi-with-mic,password.
local.host: Next method to try is publickey.
local.host: Publickey: testing agent key '/home/myusername/.ssh/id_rsa'
local.host: Public key is accepted, signing data.
local.host: Key fingerprint: SHA256:rScQOC1zgitfa/IiDb7CYwPkwK/k16ViRuAfzv4ITcQ=
Unable to connect to remote.ssh.server
Error reading response length from auth socket. at /usr/local/lib64/perl5/Net/SSH/Perl/Auth/PublicKey.pm line 104.

local.host: channel 0: new client-session
local.host: Requesting channel_open for channel 0.
local.host: Entering interactive session.


made it this far
]$

just using "ssh -v":

]$ ssh -v remote.ssh.server "uptime"
OpenSSH_7.5p1, OpenSSL 1.1.0f-fips  25 May 2017
debug1: Reading configuration data /home/myusername/.ssh/config
debug1: /home/myusername/.ssh/config line 8: Applying options for remote.ssh.server
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Reading configuration data /etc/ssh/ssh_config.d/05-redhat.conf
debug1: Reading configuration data /etc/crypto-policies/back-ends/openssh.config
debug1: /etc/ssh/ssh_config.d/05-redhat.conf line 8: Applying options for *
debug1: auto-mux: Trying existing master
debug1: Control socket "/home/myusername/.ssh/master-myusername@remote.ssh.server:22" does not exist
debug1: Connecting to remote.ssh.server xxx.xxx.xxx.xxx port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file id_rsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_7.5
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2
debug1: match: OpenSSH_7.2 pat OpenSSH* compat 0x04000000
debug1: Authenticating to remote.ssh.server:22 as 'myusername'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256@libssh.org
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: client->server cipher: aes256-gcm@openssh.com MAC: <implicit> compression: none
debug1: kex: curve25519-sha256@libssh.org need=32 dh_need=32
debug1: kex: curve25519-sha256@libssh.org need=32 dh_need=32
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:b0EOVxSO46RlNAPAeDQg66CnCsKupSxhB1Kl5ihJ9Ok
debug1: Host 'remote.ssh.server' is known and matches the ECDSA host key.
debug1: Found key in /home/myusername/.ssh/known_hosts:3
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 4294967296 blocks
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:1000)

debug1: Unspecified GSS failure.  Minor code may provide more information
No Kerberos credentials available (default cache: KEYRING:persistent:1000)

debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/myusername/.ssh/id_rsa
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug1: Authentication succeeded (publickey).
Authenticated to remote.ssh.server (xxx.xxx.xxx.xxx:22).
debug1: setting up multiplex master socket
debug1: channel 4: new /home/myusername/.ssh/master-myusername@remote.ssh.server:22
debug1: channel 5: new client-session
debug1: Entering interactive session.
debug1: pledge: id
debug1: client_input_global_request: rtype hostkeys-00@openssh.com want_reply 0
debug1: Requesting X11 forwarding with authentication spoofing.
debug1: Requesting authentication agent forwarding.
debug1: Sending environment.
debug1: Sending env LANG = en_US.utf8
debug1: Sending env XMODIFIERS = @im=none
debug1: Sending command: uptime
debug1: client_input_channel_req: channel 5 rtype exit-status reply 0
debug1: client_input_channel_req: channel 5 rtype eow@openssh.com reply 0
 15:23:01 up 50 days, 19:36,  1 user,  load average: 0.45, 0.25, 0.24
debug1: channel 5: free: client-session, nchannels 6
debug1: channel 0: free: port listener, nchannels 5
debug1: channel 1: free: port listener, nchannels 4
debug1: channel 2: free: port listener, nchannels 3
debug1: channel 3: free: port listener, nchannels 2
debug1: channel 4: free: /home/myusername/.ssh/master-myusername@remote.ssh.server:22, nchannels 1
Transferred: sent 2744, received 2564 bytes, in 0.1 seconds
Bytes per second: sent 27909.5, received 26078.7
debug1: Exit status 0

Comment on Issue with Net::SSH::Perl - can't establish connection Download Code

Replies are listed 'Best First'.
Re: Issue with Net::SSH::Perl - can't establish connection by salva (Canon) on Jul 19, 2017 at 06:00 UTC
You have two variables `$USER` and `$USERNAME` that probably should be just one. Use strict!	[reply] [d/l] [select]
Re^2: Issue with Net::SSH::Perl - can't establish connection by dayton (Acolyte) on Jul 20, 2017 at 15:33 UTC
There's a reason I have $USER and $USERNAME, but I see your point and I'll look at combining them. But that doesn't explain why the script is failing... It's reading my .ssh/config, pulling the correct key/user combo and sends them to the remote server. The remote server accepts the key, but then the script dies with the error...	[reply]
Re^3: Issue with Net::SSH::Perl - can't establish connection by salva (Canon) on Jul 21, 2017 at 06:53 UTC
`Error reading response length from auth socket. at /usr/local/lib64/perl5/Net/SSH/Perl/Auth/PublicKey.pm line 104.` That looks like the module is connecting to the local ssh agent and getting an unexpected response. Are your keys protected by a passphrase? I would run both the Perl script and the OpenSSH client with strace and see what both were doing different at the point of failure.	[reply] [d/l]
Re^4: Issue with Net::SSH::Perl - can't establish connection by dayton (Acolyte) on Jul 21, 2017 at 15:42 UTC