I have a setup where I'm running Ubuntu 11.10 as a VirtualBox guest under a Windows 7 host, behind a restrictive corporate firewall. I have set up NAT from the host port 22 to Ubuntu's port 22; IT inform me that they have opened port 22 outbound for the host machine's IP address.

I have run ssh-keygen -t rsa, and am trying to test the setup by connecting to github and another known ssh server. In both cases the connect is refused with ssh_exchange_identification: Connection closed by remote host. Full -vvv log is below.

Is this possibly still due to the corporate firewall? If so, what else might I need to request from them? Any other ideas what might be wrong and how to fix it?

~$ ssh -Tvvv [email protected]
OpenSSH_5.8p1 Debian-7ubuntu1, OpenSSL 1.0.0e 6 Sep 2011
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to github.com [207.97.227.239] port 22.
debug1: Connection established.
debug3: Incorrect RSA1 identifier
debug3: Could not load "/home/chris/.ssh/id_rsa" as a RSA1 public key
debug2: key_type_from_name: unknown key type '-----BEGIN'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'Proc-Type:'
debug3: key_read: missing keytype
debug2: key_type_from_name: unknown key type 'DEK-Info:'
debug3: key_read: missing keytype
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug3: key_read: missing whitespace
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/chris/.ssh/id_rsa type 1
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
debug1: Checking blacklist file /etc/ssh/blacklist.RSA-2048
debug1: identity file /home/chris/.ssh/id_rsa-cert type -1
debug1: identity file /home/chris/.ssh/id_dsa type -1
debug1: identity file /home/chris/.ssh/id_dsa-cert type -1
debug1: identity file /home/chris/.ssh/id_ecdsa type -1
debug1: identity file /home/chris/.ssh/id_ecdsa-cert type -1
ssh_exchange_identification: Connection closed by remote host

Edit: Requested diagnostics:

~$ ls -la ~/.ssh
total 16
drwx------  2 chris chris 4096 2012-03-30 13:12 .
drwxr-xr-x 29 chris chris 4096 2012-03-30 13:25 ..
-rw-------  1 chris chris 1766 2012-03-30 13:12 id_rsa
-rw-r--r--  1 chris chris  409 2012-03-30 13:12 id_rsa.pub