scp fails - excepted on very small files
From: Alexandre Courbot (alexandrecourbot_at_linuxgames.com)
To: email@example.com Date: Thu, 20 Nov 2003 10:23:55 +0100
When trying to scp or sftp some files, from machine A to machine B, I can get
the connection created but the file doesn't transfer. Instead it remains
stalled all the time.
Here is the log from the machine A, when the scp command is run from it:
OpenSSH_3.6.1p2 Debian 1:3.6.1p2-8, SSH protocols 1.5/2.0, OpenSSL 0x0090701f
debug1: Reading configuration data /home1/gnurou/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: Connecting to 18.104.22.168 [22.214.171.124] port 22.
debug1: Connection established.
debug1: identity file /home1/gnurou/.ssh/identity type 0
debug1: identity file /home1/gnurou/.ssh/id_rsa type -1
debug1: identity file /home1/gnurou/.ssh/id_dsa type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_3.6.1p2
debug1: match: OpenSSH_3.6.1p2 pat OpenSSH*
debug1: Local version string SSH-1.5-OpenSSH_3.6.1p2 Debian 1:3.6.1p2-8
debug1: Waiting for server public key.
debug1: Received server public key (768 bits) and host key (1024 bits).
debug1: Host '126.96.36.199' is known and matches the RSA1 host key.
debug1: Found key in /home1/gnurou/.ssh/known_hosts:7
debug1: Encryption type: 3des
debug1: Sent encrypted session key.
debug1: Installing crc compensation attack detector.
debug1: Received encrypted confirmation.
debug1: Trying RSA authentication with key '/home1/gnurou/.ssh/identity'
debug1: Server refused our key.
debug1: Doing challenge response authentication.
debug1: No challenge.
debug1: Doing password authentication.
debug1: Sending command: scp -v -t ~/
debug1: Entering interactive session.
debug1: fd 0 setting O_NONBLOCK
debug1: fd 1 setting O_NONBLOCK
Sending file modes: C0644 728948736 Mandrake92-cd3-i18n.i586.iso
Mandrake92-cd3-i18n.i586.iso 0% 140KB 4.5KB/s - stalled -d
Then everything remains stalled - on machine B, a zero-sized file is created.
When Ctrl-Cing on machine A, the scp -t process stays alive on machine B.
Trying the other way (running scp from machine B) just gives the same
However, I don't have this problem if I copy a very small file of a few bytes.
In this case everything works fine. ssh is also working great.
Machine A is behind a firewall, so this might be the problem. I suspect some
packet-size problem, or something like this. Unfortunately I have no
expertize at all regarding networking, and would really need to be able to
scp between these two machines as soon as possible.
Would anyone have any hint or explanation about this problem?