X11 forwarding fails from Mac OS 10.5.5

[Jim Basney]

Hello,

When I use an ssh client built from the openssh.org OpenSSH_5.1p1
sources on Mac OS 10.5.5 (Darwin Kernel Version 9.5.0: Wed Sep  3
11:29:43 PDT 2008; root:xnu-1228.7.58~1/RELEASE_I386 i386), I get the
following error when trying to launch an xterm in a remote ssh session:

debug1: client_input_channel_open: ctype x11 rchan 3 win 2097152 max 16384
debug1: client_request_x11: request from 127.0.0.1 54813
/tmp/launch-LP0nSk/: unknown host. (nodename nor servname provided, or
not known)
debug1: failure x11
X connection to localhost:14.0 broken (explicit kill or server shutdown).

When I use the ssh client provided by Mac OS (also OpenSSH_5.1p1), it works:

debug1: client_input_channel_open: ctype x11 rchan 3 win 2097152 max 16384
debug1: client_request_x11: request from 127.0.0.1 53387
debug2: fd 7 setting O_NONBLOCK
debug3: fd 7 is O_NONBLOCK
debug1: channel 1: new [x11]
debug1: confirm x11

I think this is a new problem that appeared when I updated to Mac OS
10.5.5 from 10.5.4.

Has anyone else seen this problem? Is there a workaround?

I'd be happy to provide more details on request.

Thanks,
Jim