OpenSSH hang ups

i'm experiencing some unusual hangups from open ssh. i'm using version: OpenSSH_3.5p1, SSH protocols 1.5/2.0, OpenSSL 0x0090602f running on Red Hat Linux Advanced Server version.

the behaviour is very intriguing, because about 90% of the commands i use work fine, but then about 1 out of 10 commands just hang, never producing any more output, and never terminating (i've given them a few days of time).

the command line i'm using is piping a tar ball to a waiting server on the other side. we're using the same mechanism on other boxes running OpenSSH_3.1p1, with no problems.

here's the command line:
/bin/tar -T - -cvzf - | ssh -v -p 2222 -a -e none -x -c blowfish -l LOGINNAME HOSTNAME i get the following output from sessions that hang:

OpenSSH_3.5p1, SSH protocols 1.5/2.0, OpenSSL 0x0090602f Pseudo-terminal will not be allocated because stdin is not a terminal.

debug1: Reading configuration data /usr/local/etc/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: ssh_connect: needpriv 0
debug1: Connecting to tsnh1.xor.com [192.225.53.76] port 2222.
debug1: Connection established.
debug1: identity file ~/.ssh/identity type 0
debug1: identity file ~/.ssh/id_rsa type 1
debug1: identity file ~/.ssh/id_dsa type 2
debug1: Remote protocol version 1.99, remote software version OpenSSH_3.4p1
debug1: match: OpenSSH_3.4p1 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_3.5p1
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client blowfish-cbc hmac-md5 none
debug1: kex: client->server blowfish-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 140/256
debug1: bits set: 1598/3191
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'HOSTNAME' is known and matches the RSA host key.
debug1: Found key in ~/.ssh/known_hosts:4
debug1: bits set: 1624/3191
debug1: ssh_rsa_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue: 

debug1: next auth method to try is publickey
debug1: try pubkey: ~/.ssh/id_rsa
debug1: authentications that can continue: 

debug1: try pubkey: ~/.ssh/id_dsa
debug1: input_userauth_pk_ok: pkalg ssh-dss blen 434 lastkey 0x808ba30 hint 2
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debug1: read PEM private key done: type DSA
debug1: ssh-userauth2 successful: method publickey
debug1: fd 4 setting O_NONBLOCK
debug1: fd 5 setting O_NONBLOCK
debug1: channel 0: new [client-session]
debug1: send channel open 0
debug1: Entering interactive session.
debug1: ssh_session2_setup: id 0
debug1: channel request 0: shell
debug1: channel 0: open confirm rwindow 0 rmax 32768

i get identical output from sessions that don't hang, only they include the following as well:

debug1: channel 0: read<=0 rfd 4 len 0
debug1: channel 0: read failed
debug1: channel 0: close_read
debug1: channel 0: input open -> drain
debug1: channel 0: ibuf empty
debug1: channel 0: send eof
debug1: channel 0: input drain -> closed
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: rcvd eof
debug1: channel 0: output open -> drain
debug1: channel 0: obuf empty
debug1: channel 0: close_write
debug1: channel 0: output drain -> closed
debug1: channel 0: rcvd close
debug1: channel 0: almost dead
debug1: channel 0: gc: notify user
debug1: channel 0: gc: user detached
debug1: channel 0: send close
debug1: channel 0: is dead
debug1: channel 0: garbage collecting
debug1: channel_free: channel 0: client-session, nchannels 1
debug1: fd 0 clearing O_NONBLOCK
debug1: fd 1 clearing O_NONBLOCK
debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.7 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
debug1: Exit status 0

we don't know if the problem's in the openSSH, or the os, or some hardware, or anywhere, but i thought i'd just mention it to y'all to see if it sounded familiar or if you could make any suggestions about how to fix.

thanks

-- 
Darin Kelkhoff  -  Programmer
darink@sportingnews.com  -  314.991.6623
The Sporting News  -  www.sportingnews.com

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