Unable to SSH into machine - ssh_exchange_identification: Connection closed by remote host

Linux and Unix-Like Red Hat
1

For a few days now I have been experiencing issues when trying to SSH into 1 of my machine. I get the following output when running 'ssh -vvv':

server1:/home/mymadq> ssh -l root -vvv server2
OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to server2 [138.54.45.50] port 22.
debug1: Connection established.
debug1: identity file /home/user1/.ssh/identity type -1
debug3: Not a RSA1 key file /home/user1/.ssh/id_rsa.
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
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/user1/.ssh/id_rsa type 1
debug1: identity file /home/user1/.ssh/id_dsa type -1
ssh_exchange_identification: Connection closed by remote host
server1:/home/user1>
2

I would say user1's private key file is corrupt for some reason (/home/user1/.ssh/id_rsa).
If view the file and compare it to another private key file (you can generate an example keyfile using something like: "ssh-keygen -t rsa -f foobar")

3

If you don't have another private key to compare with, then you'll need to re-generate you key pairs, but first, delete the .ssh folder in your ~. And probably generate a dsa keytype which supports ssh version 2 better

server2:/home/user1>ssh-keygen -t dsa

---------- Post updated at 09:54 AM ---------- Previous update was at 09:54 AM ----------

If you don't have another private key to compare with, then you'll need to re-generate you key pairs, but first, delete the .ssh folder in your ~. And probably generate a dsa keytype which supports ssh version 2 better

server2:/home/user1>ssh-keygen -t dsa

4

Personally, I wouldnt recommend deleting the .ssh dir in your home directory. It may contain other files that you use (known host keys, other personal trusted keys, etc).
If you delete files, within .ssh, begining with "id_*" you should be fine.

Judging from your original post you were using "rsa" keys, so you will need "-t rsa" as opposed to "-t dsa".

I hope this helps...