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I'm having an issue connecting to servers via ssh at work over wireless (haven't tried over ethernet). Whenever I try to connect to any server with ssh within our network, I receive a password prompt, I type the password, hit enter, and ssh hangs for minutes. After a few minutes, I end up having to kill the ssh command.

Funny thing is I can connect to the servers via putty on wine, but this is not ideal. The problem seems limited to the openssh client.

I've tried the following:
- clearing out my ~/.ssh/known_hosts file
- booting an older kernel
- clearing local DNS cache with nscd
- setting UseDNS no in /etc/ssh/sshd_config on server (as suggested by @fuscata)
- setting up kerberos on my client (as suggested by @fuscata)
- running ssh mark@localhost and was able to get in on my local machine (as suggested by @Alex Holst)

The only recent change I can think of is my work recently changed access points. Weird how putty works but the openssh client does not.

Any suggestions?

I'm running Ubuntu 10.10.

Kernel:

$ uname -a
Linux mark-think 2.6.35-28-generic #50-Ubuntu SMP Fri Mar 18 18:42:20 UTC 2011 x86_64 GNU/Linux

Wireless:

$ lspci | grep -i broadcom
12:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g LP-PHY (rev 01)

NMAP of Server (ssh port open):

$ nmap myserver -PN

Starting Nmap 5.21 ( http://nmap.org ) at 2011-09-20 10:16 EDT
Nmap scan report for myserver (ip.address.to.server)
Host is up (0.091s latency).
Not shown: 993 filtered ports
PORT     STATE SERVICE
22/tcp   open  ssh
111/tcp  open  rpcbind
3389/tcp open  ms-term-serv
4848/tcp open  unknown
7676/tcp open  unknown
8080/tcp open  http-proxy
8181/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 7.98 seconds

SSH Connect Log:

$ ssh root@myserver -vvv

OpenSSH_5.5p1 Debian-4ubuntu6, OpenSSL 0.9.8o 01 Jun 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to myserver [ip.address.to.server] port 22.
debug1: Connection established.
debug1: identity file /home/mark/.ssh/id_rsa type -1
debug1: identity file /home/mark/.ssh/id_rsa-cert type -1
debug1: identity file /home/mark/.ssh/id_dsa type -1
debug1: identity file /home/mark/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.8p1 Debian-7
debug1: match: OpenSSH_5.8p1 Debian-7 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.5p1 Debian-4ubuntu6
debug2: fd 3 setting O_NONBLOCK
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: kex_parse_kexinit: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
debug2: kex_parse_kexinit: ssh-rsa,ssh-dss
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: none,zlib@openssh.com
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: 
debug2: kex_parse_kexinit: first_kex_follows 0 
debug2: kex_parse_kexinit: reserved 0 
debug2: mac_setup: found hmac-md5
debug1: kex: server->client aes128-ctr hmac-md5 none
debug2: mac_setup: found hmac-md5
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug2: dh_gen_key: priv key bits set: 118/256
debug2: bits set: 528/1024
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug3: check_host_in_hostfile: host myserver filename /home/mark/.ssh/known_hosts
debug3: check_host_in_hostfile: host myserver filename /home/mark/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 2
debug3: check_host_in_hostfile: host ip.address.to.server filename /home/mark/.ssh/known_hosts
debug3: check_host_in_hostfile: host ip.address.to.server filename /home/mark/.ssh/known_hosts
debug3: check_host_in_hostfile: match line 3
debug1: Host 'myserver' is known and matches the RSA host key.
debug1: Found key in /home/mark/.ssh/known_hosts:2
debug2: bits set: 549/1024
debug1: ssh_rsa_verify: signature correct
debug2: kex_derive_keys
debug2: set_newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug2: set_newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug2: key: /home/mark/.ssh/id_rsa ((nil))
debug2: key: /home/mark/.ssh/id_dsa ((nil))
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /home/mark/.ssh/id_rsa
debug3: no such identity: /home/mark/.ssh/id_rsa
debug1: Trying private key: /home/mark/.ssh/id_dsa
debug3: no such identity: /home/mark/.ssh/id_dsa
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
root@myserver's password:
debug3: packet_send2: adding 64 (len 59 padlen 5 extra_pad 64)
debug2: we sent a password packet, wait for reply
debug1: Authentication succeeded (password).
debug2: fd 5 setting O_NONBLOCK
debug3: fd 6 is O_NONBLOCK
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.
debug2: callback start
debug2: x11_get_proto: /usr/bin/xauth  list :0.0 2>/dev/null
debug1: Requesting X11 forwarding with authentication spoofing.
debug2: channel 0: request x11-req confirm 0
debug2: client_session2_setup: id 0
debug2: channel 0: request pty-req confirm 1
debug1: Sending environment.
debug3: Ignored env ORBIT_SOCKETDIR
debug3: Ignored env SSH_AGENT_PID
debug3: Ignored env GIO_LAUNCHED_DESKTOP_FILE_PID
debug3: Ignored env TERM
debug3: Ignored env SHELL
debug3: Ignored env XDG_SESSION_COOKIE
debug3: Ignored env WINDOWID
debug3: Ignored env GNOME_KEYRING_CONTROL
debug3: Ignored env GTK_MODULES
debug3: Ignored env USER
debug3: Ignored env LS_COLORS
debug3: Ignored env SSH_AUTH_SOCK
debug3: Ignored env DEFAULTS_PATH
debug3: Ignored env SESSION_MANAGER
debug3: Ignored env USERNAME
debug3: Ignored env GIO_LAUNCHED_DESKTOP_FILE
debug3: Ignored env XDG_CONFIG_DIRS
debug3: Ignored env DESKTOP_SESSION
debug3: Ignored env PATH
debug3: Ignored env PWD
debug3: Ignored env JAVA_HOME
debug3: Ignored env GDM_KEYBOARD_LAYOUT
debug1: Sending env LANG = en_US.UTF-8
debug2: channel 0: request env confirm 0
debug3: Ignored env GNOME_KEYRING_PID
debug3: Ignored env MANDATORY_PATH
debug3: Ignored env GDM_LANG
debug3: Ignored env GDMSESSION
debug3: Ignored env SHLVL
debug3: Ignored env HOME
debug3: Ignored env GNOME_DESKTOP_SESSION_ID
debug3: Ignored env LOGNAME
debug3: Ignored env CLASSPATH
debug3: Ignored env XDG_DATA_DIRS
debug3: Ignored env DBUS_SESSION_BUS_ADDRESS
debug3: Ignored env LESSOPEN
debug3: Ignored env WINDOWPATH
debug3: Ignored env DISPLAY
debug3: Ignored env LESSCLOSE
debug3: Ignored env XAUTHORITY
debug3: Ignored env COLORTERM
debug3: Ignored env _
debug2: channel 0: request shell confirm 1
debug2: fd 3 setting TCP_NODELAY
debug2: callback done
debug2: channel 0: open confirm rwindow 0 rmax 32768
debug1: channel 0: free: client-session, nchannels 1
debug3: channel 0: status: The following connections are open:
  #0 client-session (t4 r0 i0/0 o0/0 fd 4/5 cc -1)

debug3: channel 0: close_fds r 4 w 5 e 6
debug1: fd 1 clearing O_NONBLOCK
debug3: fd 2 is not O_NONBLOCK

*** Hangs right here... ***
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Mark Bouchard
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  • I would suspect a routing issue - can you connect to these machines using some other protocol than ssh? Say, hit a web page on these machines via the wireless connection? – malcolmpdx Sep 20 '11 at 14:27
  • @malcolmpdx Yeah there is a group of 3 servers. One of them is a web server and I am able to hit that via my browser. However, with SSH I am unable to connect to that server either. – Mark Bouchard Sep 20 '11 at 14:38
  • What's the behaviour if you type an incorrect password? – nickgrim Sep 20 '11 at 14:50
  • @nickgrim I get "Permission denied, please try again." – Mark Bouchard Sep 20 '11 at 14:53
  • I've seen this on OpenBSD clients connecting to Ubuntu 10.10. I never got around to fixing, but I think I found out that if you type commands when it "hangs", you can actually execute the commands you type. On Ubuntu, can you ssh to localhost without problems? If not, report a bug to Ubuntu. If so, report a bug to the OpenSSH folks. – Alex Holst Sep 21 '11 at 21:51
  • @Alex Holst: Yeah, I was able to do `ssh mark@localhost` on my local machine and was able to log in. – Mark Bouchard Sep 22 '11 at 15:25

2 Answers2

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Try adding this line to /etc/ssh/sshd_config on the server:

UseDNS no

and reload ssh

If that doesn't work, you might try installing krb5-config on the client (This solved the problem for me on Ubuntu 7.04, obviously quite a long time ago.):

sudo apt-get install krb5-config
xofer
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  • Thanks! I'll give both of these a try and let you know tomorrow how it turns out. – Mark Bouchard Sep 20 '11 at 21:46
  • Thanks for the clarification for the server/client changes. I tried modifying the sshd_config file on the server and restarting ssh with no luck logging in with my openssh client. I also installed krb5-config and that didn't seem to help either. How would kerberos help my openssh client? It could be because I don't know what settings I should put when configuring kerberos (left everything blank). – Mark Bouchard Sep 21 '11 at 13:41
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I left my old job so I no longer have this issue. Unfortunately, I never was able to get the SSH client to work as expected.

Mark Bouchard
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