I have 3 debian etch machines 2.6.18-5-686 kernel .I can connect by
ssh from the gateway machine to the back end servers by key exchange
of dsa keys ,the two bak end servers can connect with each other , but
both do not connect with the gateway server,sorry they connect but
than connection drops because authentication .The sshd on this
machine is running on a not default port 666 , has sftp not enabled ,
root login not allowed and password authentication allowed because
users connecting from internet.This is the client output when i
connect to the sshd on the gateway machine:
gabrix@www:~$ ssh -p 666 gabrix@192.168.1.2 -vvv
OpenSSH_4.3p2 Debian-9, OpenSSL 0.9.8c 05 Sep 2006
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to 192.168.1.2 [192.168.1.2] port 666.
debug1: Connection established.
debug1: identity file /home/gabrix/.ssh/identity type -1
debug3: Not a RSA1 key file /home/gabrix/.ssh/id_rsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
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/gabrix/.ssh/id_rsa type 1
debug3: Not a RSA1 key file /home/gabrix/.ssh/id_dsa.
debug2: key_type_from_name: unknown key type '-----BEGIN'
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
debug2: key_type_from_name: unknown key type '-----END'
debug3: key_read: missing keytype
debug1: identity file /home/gabrix/.ssh/id_dsa type 2
ssh_exchange_identification: Connection closed by remote host

The Debian on the gateway machines is a freh install.By sshfs i
mounted gabrix home dir on it and copied .ssh/id_dsa.pub >> /home/
gabrix.ssh/authorized_keys on the gateway machine but autentication
doesn't work.After the instal i managed to make the first login than i
generated keys and authentication after one or two key exchange logins
stopped working.Logs on the server don't say much and they are on
sysklog as AUTH.DEBUG.

ok all right right now i found on a auth.* login.log "connection
refused by tcp wrapper " where i have all bogons ip starting from ALL:
0.0.0.0/8 on a /etc/hosts.deny.Cheers anyway cause writing the mail to
you i was trying to collect as many infos as i could to make your life
easier to help me out
..
thank you !