Hello.

I'm trying to use PuTTY v5.8 from a Windows 7 Desktop to log into an Red Hat Linux Enterprise Server and I'm getting the following error:

I believe that all of the Red Hat Linux systems are setup correctly, with the following.

/etc/hosts.allow has the IP addres of the computer that I'm using at access the server

/etc/ssh/ssh_config has the following entry: ciphers aes128-ctr, aes192-ctr and aes256-ctr

/etc/sysconfig/iptables has the following entry: -A INPUT -s (my ip address) -p tcp -m tcp --dport 22 -j ACCEPT

I think I have the Linux servers ok, and I am able to SSH into other Linux servers too, so I've tried to match the PuTTY settings so they match the ones that I can't get to Vs the ones that I can get to.

I am not sure what I'm missing or what I'm not doing.

It has been recommended to upgrade the PuTTY client, however I also wanted to get others input.

thanks

You need to add a "Ciphers" line to /etc/ssh/sshd_config (or modify the existing line) to include at least one cipher supported by PuTTY, and then either restart or SIGHUP the sshd process so that it re-reads its configuration.

Note that /etc/ssh/sshd_config is different from the /etc/ssh/ssh_config file, which is for ssh clients running on the host. The /etc/ssh/sshd_config file is for the ssh server running on the host (which is what your PuTTY ssh client is connecting to). The contents of /etc/ssh/ssh_config has no effect on connections to the server.

See also the "Ciphers" section of http://linux.die.net/man/5/sshd_config

Alternatively, if the latest version of PuTTY supports one of the ciphers the server is configured to use, then upgrading PuTTY would also work.

Forgot to mention, when checking /etc/sshd/sshd_config, the following entry is found:

Ciphers aes128-ctr,aes192-ctr,aes256-ctr


I am going to upgrade my PuTTY Client from v5.8 to v6.0 (its the version approved by out info sec deptartment) to see if that fixes the issue.

thanks

Have updated the PuTTY client from v5.8 to v6 and that fixed the issue.

Thanks.