If you use Google Apps and have Linux machines you access via SSH, this is a handy method to add two-factor authentication to your environment:
When Google introduced two-factor authentication for the Google and Google Apps accounts, they also created a pluggable authentication module PAM for Linux. This is great news for people running Linux servers who want to protect their remotely-accessible SSH accounts with two-factor authentication. For free.
via Two-factor SSH authentication via Google secures Linux logins | TechRepublic.
Surprisingly and happily, with ESXi 4.1, VMware has made it possible to enable and disable SSH access to the host via the vSphere client. No longer is it necessary to enter the top-secret unsupported console via <alt-F1> and edit inetd.conf by hand.
To enable local or remote TSM from the vSphere Client:
- Select the host and click the Configuration tab.
- Click Security profile > Properties.
- Click Local Tech Support or Remote Tech Support SSH and click Options.
- Choose the desired startup policy and click Start, then click OK.
- Verify that the daemon selected in step 3 shows as running in the Services Properties window.
via VMware KB: Using Tech Support Mode in ESXi 4.1.