On Thu, Sep 25, 2008 at 03:51:54PM -0500, COHEN, STEVEN M (ATTSI) wrote:
> I am trying to connect via ssh from a box running UnixWare 5 7.1.3 which has
> OpenSSH installed at version OpenSSH_5.0p1, OpenSSL 0.9.8g 19 Oct 2007 to a
> box running
> Linux 2.6.9-78.0.1.EL #1 Tue Jul 22 17:50:01 EDT 2008 which has OpenSSH
> installed at version OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003.
>
> I find that the keys generated on the Unixware box are not accepted on the
> Linux box. This authentication always fails and I am forced to type the
> passphrase in every time.


http://wooledge.org/mywiki/SshKeys

Not a comprehensive write-up of EVERY conceivable problem, but it does
cover the most common ones.