ssh problems with 7.0-BETA1

I have an odd problem with ssh on FreeBSD 7.0-BETA1, trying to connect
to sshd on 6.2-RELEASE-p8/amd64.  So far,  it's not making any sense to
me, so please bear with me as I try to explain it.

On my home network, I have several machines running 7.0-BETA1,  both
amd64, and i386 versions.  all machines get updated sources, and built
world every morning.
I also have 6.2-STABLE as well as RELENG_6_2 machines, on the same network.

I have one specific machine,  that none  of my 7.x machines can connect
to via ssh.  using ssh in verbose mode doesn't offer anything in the way
of diagnostics or hints.  my 6.x machines can connect to it fine.

Logging into the remote machine,  I can run wireshark/tcpdump,  and the
tcp conversation looks like this:

tcp handshake.
6.2 server sends version
7.x client sends version
7.x client sends a  TCP Retransmission Unreassembled Packet to 6.x sshd
6.x sshd sends a RST, and that is the end of it.

The ssh -vvvv user_at_host output ends in:
debug1: Remote protocol version 2.0, remote software version
OpenSSH_4.5p1 FreeBSD-20061110
debug1: match: OpenSSH_4.5p1 FreeBSD-20061110 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.5p1 FreeBSD-20061110
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
Read from socket failed: Connection reset by peer



Connections from the 6.2 box to any of the 7.x boxes work fine,  and
additionally connections from the 7.x box to *any other* 6.x box works. 
It's just this one specific machine.
to re-iterate,  the 6.x boxes can connect to this machine fine.  it's
only the 7.x boxes that get the error.

Please let me know if I can provide more details,  also  I recieve
current_at_ in daily digest mode, so please CC: me any replies.

Thanks in advance.

Jeff Palmer
jpalmer _at_freenode IRC ##FreeBSD