Web Hosting Talk : Web Hosting Main Forums : Dedicated Server : Backdoor solution for dedicated servers

[Valentin Mitoiu]

Hi guys,

I was wondering about something.

Does a solution exists like a backdoor (ssh, etc) that is running even if the server is in high load and a user can't log in.

I'm referring to something that has like a restricted memory space and always runs even if the server is unreachable.

[beastserv]

you have the option to attach an off-band terminal to your server, KVM over IP is the way it's done today.

[Valentin Mitoiu]

True, but this is dependent to the server provider and can also be unavailable for purchasing.

I am referring to a software solution.

[bloodyman]

Software use system resources. If they are busy, software will not work. You can try change priority of ssh deamon for higher value to be sure that first free resource will be used for ssh.

[Valentin Mitoiu]

I was thinking more on patching the kernel and allocate a particular amount of resources to a specific process and keeping those resources exclusive.

In this way those specific resources are always seen as occupied.

[globichen]

I know that Juniper does this for their Routers, but I have never heard about this for an operating system running on a dedicated server.
Your best bet would be to have a server that comes with some sort of IPMI, which is not OS dependant. I know this is not what you're looking for, but it's as close as possible to what you need.

[Valentin Mitoiu]

Thank you all for your replies

I'll look more into this and update the thread if I find something software based.

[bodmark]

If you were running a cloud server, you will not need a KVM over IP as most hardware virtualization cloud hosting provider offer VM console and it just works fine.

[ishan]

Virtualizing your server as bodmark suggests would allow you to leave some resources available for main node at all times and you can access the Virtual server from within the main node.

[Dave Parish]

I setup esxi specifically for this reason on my own servers. ddos, ssh crashes, you can still console the server and do what needs to be done to get it back up. With v5 and para virtualization the speed ups are worth it.

[rds100]

"Backdoor" is a terrible name for this. Call it "Out Of Band Management" instead. And yes, this is exactly what IPMI is for. If you don't have IPMI, you can do the virtualization magic.

[Host Ultra]

Also useful is watchdog.
It will reboot your server automatically if the OS stops responding.