Suddenly I get "Server refused to allocate pty"
Posted: 12 Jun 2013, 12:34
A few days ago I set up passwordless ssh on a very clean b3 install. It was working from Windows (PuTTY & Command Prompt) and a Linux PC. Last night my Windows machine rebooted (thank you Windows Update) killing two or three b3 console sessions. When I tried to ssh back in using PuTTY I couldn't using the previous passwordless method.
Every time I try to ssh with a passwordless key from Windows (PuTTY or Command Prompt), the key is authenticated but I get the error "Server refused to allocate pty". From the Windows Command Prompt console (using cygwin or OpenSSH - I forget which!) ssh also fails but with a slightly different error message: "PTY allocation request failed on channel 0"
I can ssh and login with password, just not using passwordless authentication. I rebooted b3 but the problem remains.
ssh -vvv reveals:
Everything seems ok on b3 (e.g. in /dev/devpts is mounted on /dev/pts), so I'm not sure why it has started to fail.
Another strangeness - I set up passwordless ssh so that I could automate rsync from Windows 7 Task Manager to b3. This appears still to be working - so b3 is presumably accepting passwordless keys in some situations, but no longer from the previously working PuTTY configuration.
Any ideas?
Thanks,
Mark
Every time I try to ssh with a passwordless key from Windows (PuTTY or Command Prompt), the key is authenticated but I get the error "Server refused to allocate pty". From the Windows Command Prompt console (using cygwin or OpenSSH - I forget which!) ssh also fails but with a slightly different error message: "PTY allocation request failed on channel 0"
I can ssh and login with password, just not using passwordless authentication. I rebooted b3 but the problem remains.
ssh -vvv reveals:
Code: Select all
[snip]
debug1: Authentication succeeded (publickey).
Authenticated to b3 ([192.168.1.n]:22).
debug1: channel 0: new [client-session]
debug3: ssh_session2_open: channel_new: 0
debug2: channel 0: send open
debug1: Requesting no-more-sessions@openssh.com
debug1: Entering interactive session.
debug1: Remote: Port forwarding disabled.
debug1: Remote: Pty allocation disabled.
debug2: callback start
debug2: fd 3 setting TCP_NODELAY
debug3: packet_set_tos: set IP_TOS 0x10
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug2: channel 0: request shell confirm 1
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug2: channel_input_status_confirm: type 100 id 0
PTY allocation request failed on channel 0
debug2: channel 0: rcvd adjust 2097152
debug2: channel_input_status_confirm: type 99 id 0
debug2: shell request accepted on channel 0
Linux b3 2.6.39.4-11 #1 Tue Apr 3 21:45:12 FET 2012 armv5tel
[snip]Another strangeness - I set up passwordless ssh so that I could automate rsync from Windows 7 Task Manager to b3. This appears still to be working - so b3 is presumably accepting passwordless keys in some situations, but no longer from the previously working PuTTY configuration.
Any ideas?
Thanks,
Mark
