Remote Management with OpenIPMI
IPMI means Intelligent Platform Management Interface. This is integrated on a BMC and it's independant form the OS. You can use IPMI to remotely control you server, Example: Power up/down for emergency, monitoring, serial console over LAN...
OpenIPMI is an Open Source implementation of the IPMI standard.
apt-get install ipmitool
Tools to help manage IPMI hosts
In the days of serial consoles one had serial console servers which could provide inband and out of band access to a server console and also provide logging of all console messages and console access.
There are a few opensource tools which can do something simmilar for IPMI SOL consoles:
conlog - tmux based IPMI serial-over-lan logging program