Synergy is a nifty tool for cross platform clipboard, keyboard and mouse sharing. It's reasonably easy to configure synergy server for use with multiple synergy clients.

Doing so will spare you some time while working on multiple computers at your desk at once. I use it at office to connect my laptop's and office computer mouse, keyboard and clipboard and thus reducing or completely eliminating need to lean over my laptop every time I need to use it. Anyway, most of the people use it with quicksynergy wrapper allowing even easier setup, but what the synergy lack is a means of authentication and security in data transfers. I'll try to guide you how to make a secure synergy setup on untrusted networks.

Probably lots of you are behind some sort of very restrictive corporate firewall. Unable to access your office pc from home because of firewall policies. In normal cases this scenario is more than welcomed. No outsiders should be allowed to access internal parts of secure network! Ideally companies will setup secure VPN access allowing its employees to access their work computers and do some work remotely. What if you aren't one of the lucky ones having such option? You desperately need to access your office pc?

Using ssh and its functionality should be a second nature to all Linux sysadmins, for some users some aspects of ssh are still a mystery, so let's shed some light on it. Here you will not learn basics shell commands and usage, I will simply try to explain usage of ssh protocol itself, and it benefits. How to use ssh, how to setup keys, how to use ssh agent that will enable some extra functionality for programs like scp, rsync, etc.

By default xen tools comes with only one network interface enabled for your dom0 and domU machines. So what if you want to add some more? It's actually very simple.

All you need to do is run:

/etc/xen/scripts/network-bridge start vifnum=1 netdev=eth1 bridge=xenbr1

This will effectively create one extra xenbr attached to eth1 interface. You can repeat the above command for all your interfaces, and you can stop them in the same manner, just replace start with stop.

Lately I was playing with stock xen kernel and virtualization, and I came across one relatively big problem. Let’s say I want to share my guest machines to, let’s say clients. You must give them root… because that’s whats VPS-es all all about, having root access to OS without having to purchase expensive hardware. Having that in mind they are by default untrusted and unpredictable, they can do god knows what in there!

So what caught my eye?

By default xen, and available management tools, don’t really have a way of sorting out IP conflicts in bridged mode. Basically you have bunch of scripts that will provision VPS alongside with IP address. Looking at the conf files you have vif and IP declarations in vm_xen.conf file.