I had a look at the Deja archive, but I didn't seem to pick up what I
might be doing wrong. I built SSH 1.2.27 on my RedHat system and all
seems well except for X forwarding.
If I connect to this box with the '-v' option, I see,
% ssh -v 192.168.0.1
SSH Version 1.2.27 [i386--freebsd3.2], protocol version 1.5.
Compiled with RSAREF.
client.mydomain.com: Reading configuration data /usr/home/cjc/.ssh/config
client.mydomain.com: Reading configuration data /usr/local/etc/ssh_config
client.mydomain.com: ssh_connect: getuid 1001 geteuid 1001 anon 1
client.mydomain.com: Connecting to 192.168.0.1 port 22.
client.mydomain.com: Connection established.
client.mydomain.com: Remote protocol version 1.5, remote software version 1.2.27
client.mydomain.com: Waiting for server public key.
client.mydomain.com: Received server public key (768 bits) and host key (1024 bits).
client.mydomain.com: Host '192.168.0.1' is known and matches the host key.
client.mydomain.com: Initializing random; seed file /usr/home/cjc/.ssh/random_seed
client.mydomain.com: Encryption type: idea
client.mydomain.com: Sent encrypted session key.
client.mydomain.com: Installing crc compensation attack detector.
client.mydomain.com: Received encrypted confirmation.
client.mydomain.com: Remote: Server does not permit empty password login.
client.mydomain.com: Connection to authentication agent opened.
client.mydomain.com: Received RSA challenge from server.
client.mydomain.com: Sending response to RSA challenge.
client.mydomain.com: Remote: RSA authentication accepted.
client.mydomain.com: RSA authentication accepted by server.
client.mydomain.com: Requesting pty.
client.mydomain.com: Failed to get local xauth data.
client.mydomain.com: Requesting X11 forwarding with authentication spoofing.
client.mydomain.com: Requesting authentication agent forwarding.
client.mydomain.com: Requesting shell.
client.mydomain.com: Entering interactive session.
Last login: Sun Oct 24 23:21:24 1999 from 192.168.0.204
And that all looks OK... at least that is exactly how the output looks
when I connect to a machine where the X forwarding works.
If I try to start an xterm, the session just kind of hangs. I can look
at 'ps' output and yes, there is an xterm running... but where it is
living I don't know (the DISPLAY variable is being set to
'192.168.0.1:10.0', BTW). It never shows up and a tcpdump reveals that
no efforts are going on to bring it to life on my machine.
This machine is a firewall, but on this internal interface, there
should be no issues (and SSH is allowed in and out anyway). SSH works
fine among my other clients and servers, and I don't know what is
different about this machine, other than being the only RH Linux
one. Old DejaNews message talked about hosts.allow, but the sshd
daemon runs independently, I don't see how it would be effected.
Any ideas on what might be going on here? Thanks.
 I had a FreeBSD 3.x machine who didn't like to allow X
forwarding. However, processes were never spawned, I would get
timeouts. It disappeared last OS upgrade, never really understood
what was wrong. It works fine now.