Conc Manual

Table of Contents
The Server: concserv
The Client: conc
The Client: console
Known Bugs and Limitations


Conc is a software package that allows a Linux machine, or a group of machines, to be used as a serial console concentrator. Each console connected to the system may have its output logged, and clients running either locally or on remote hosts may connect to any client. Multiple connections to a single console line are permitted.

This document describes version 1.1 of the Conc package.


The systems consists of three components. The first is concserv, the central daemon, that keeps logs from all the consoles and coordinates the rest of the system. When it starts, concserv spawns a number of termserv processes that control the serial lines to which the console lines are connected. The link between a termserv and concserv is encrypted and termservs may run on separate machines to concserv, communicated over TCP/IP.

The final component, conc, is the user interface. It connects to concserv over an encrypted TCP/IP link, and allows the system administrator to view the logs of a particular machine, connect to its console, add and remove consoles etc. There is also a small, text-based interface called console that allows connection to a single console.

Any number of user interface programs may run concurrently and multiple connections to the same are possible, allowing groups to work on one system. Having all the components communicate by TCP/IP allows administration of machines from off site or unifying management of co-located and local equipment.

This arrangement is illustrated in Figure 1>

Figure 1. Overview of the Conc System