I can ssh into the Linux box from other machines(win10) on the same subnet. But when I attempt to ssh from a win10 on a different subnet, the login prompt is returned but the password prompt is never shown.

I've checked hosts.allow/hosts.deny and all the iptables are set to any proto anywhere. The Linux box can ping the win10 on the different subnet.

The network speed between the two is slower than a normal net topo because of the type of wireless link for the nets.

The sshd status shows that a connection was made but the client side is not prompted for a password.

What could explain this? Can it be fixed?

*** Added. Just as a second thought too. I'm having rdp issues from the same computers as the ssh. I haven't updated the sshd_config with UseDNS no yet. I will update when that's done of any changes. thanks.

  • the putty logs show the following message is being sent but there is no reply SSH_MSG_USERAUTH_REQUEST – J.Alex Dec 26 '17 at 8:08
  • Please specify exact sshd version - if it comes from your linux distro, your specification should include that as well, in order to identify the set of patches applied to it. E.g. older versions of SSH were notorious for querying the reverse DNS of the client, wiriting paranoid log messages, and causing delays if the DNS server did not respond to the request. You also want to check the logs for SSH on the server. – sourcejedi Dec 26 '17 at 8:50
  • I get the same issue with the following command. C:\tools\putty.exe -load session_name -l your_user_name -pw your_password – J.Alex Dec 26 '17 at 8:57
  • @sourcejedi OpenSSH_6.6.6p1 OpenSSL 1.0.1e-fips 11FEB 2013 – J.Alex Dec 26 '17 at 9:15

In PuTTY, the login prompt is created by the PuTTY client, but the password prompt comes from the server side.

Can the server route traffic back to the client's subnet?

Some Linux distributions have ssh configured to make a DNS lookup for the client's hostname by default: if this fails, this can cause a long delay, especially if GSSAPI authentication methods are also enabled. If the total delay becomes too long, the connection attempt may time out.

  • The putty logs show (Outgoing)client -> server and (Incoming)server -> client traffic. Does the DNS lookup become a problem during login/auth? The user on the linux box does not have rights to update the sshd_config with UseDNS no. I would have to do that later today. – J.Alex Dec 26 '17 at 9:20
  • DNS lookup problems typically slow down the appearance of the password prompt, yes. – telcoM Dec 26 '17 at 9:24

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