Stuff I'm Up To

Technical Ramblings

vSphere SSH failed to connect to host — November 17, 2017

vSphere SSH failed to connect to host

When trying to apply patches to one of our ESXi 6.0 hosts I found I couldn’t connect to it using ssh. Stopping and starting SSH from vCenter didn’t work. Neither did disabling/enabling from the DCUI.

From my client I’d see:

ssh_exchange_identification: Connection closed by remote host

So then I resorted to checking out the server from the console. First make sure I stopped SSH from either of the GUI’s.

Use ALT-F1 at the DCUI and logon to the host using your root account.

Then I tried to start sshd as a daemon using:

# /usr/lib/vmware/openssh/bin/sshd -D

Which reported errors Unsupported option running and Unsupported option PrintLastLog

So I editted my /etc/ssh/sshd_config file. Don’t know what caused it. But it was just a # missing from the first line. I guess I must have spannered it at some point when editing it to disable some ciphers. But the good news is using this method I can at least get some clear output from sshd -D to tell me why it wasn’t starting properly.

# running from inetd
# Port 2200
Protocol 2
HostKey /etc/ssh/ssh_host_rsa_key
HostKey /etc/ssh/ssh_host_dsa_key

UsePrivilegeSeparation no

SyslogFacility auth
LogLevel info

PermitRootLogin yes

PrintMotd yes
PrintLastLog no

TCPKeepAlive yes

X11Forwarding no

...

So just to be safe I checked the other hosts and copied an sshd_config from one of the known good ones.

Advertisements
Flash Update KB4034662 — August 17, 2017

Flash Update KB4034662

Two of our Windows 2012R2 servers constantly failed to apply Windows Updates. They’d start deploying the updates but every time a reboot was required the updates would all roll back.

After several weeks of various members of the IT team banging their heads on their desks and the walls, I stepped up and took a look at the problem. It was a real doozy. Took me ages trying to figure out what was going on.

It all turned out to be down to one update for Flash player! We don’t even use flash player on any of the servers.

Continue reading

Debian Installation — September 20, 2016

Debian Installation

When I setup a Debian server there’s a few basic things I do to get it online.

First steps boot from the netinst CD and follow the installer.

First logon using SSH as your regular user account as root can’t access the system remotely. So you’ll have to logon unprivileged and then su to root.

$ su

Sudo

Then before doing anything else install sudo and give your user account access by making them a member of the sudo group.

# apt-get install sudo
# usermod -a -G sudo [user]

You’ll have to logout and back in to pick-up the sudo group change.

Continue reading