Console server
A console server ( English: Console Server ) is a remote maintenance component and is used for management of computer network nodes that are more likely to be found in the data center, such as ( Unix ) servers, routers, switches, firewalls, PBXs, UPSs. Components connected nodes only require a serial interface.
Meaning the console server is to ensure the operability of the connected nodes even with a failure of the node or the computer network (LAN). The serial console is it still possible to perform from a distance, for example, emergency maintenance at a network component or re-configure the network interface for a server. Since the last piece to node not on the LAN, so in-band takes place, one also speaks of out-of -band management, OOB short. For reasons of availability and safety, it is advisable to close console server to a dedicated management network.
Operation
A console server has up to 48 serial ports and at least one Ethernet port, which makes available over TCP serial interfaces on the node. Some console servers also feature a built-in modem, ISDN cards, or the possibility of retrofitting, eg via USB or PCMCIA.
Most console servers provide the first support a FIFO buffer ( first in first out ), which temporarily stores the last messages of the monitored device. Using this stored information, the cause of an error can easily identify and solve. Some makers of console servers provide a pattern recognition based on strings like "Panic " or " Ok" on the console can trigger an alarm ( E- mail, SNMP, SNMP traps ).
Standards
Meanwhile, the encrypted access to the console server via Secure Shell ( SSH) and the connected nodes is mandatory. Makes sense or common in multiple console servers in addition to the local authentication via a remote services such as RADIUS, LDAP, or TACACS . In addition, both the configuration of the console server and the access to the connected node via a convenient web interface is enabled by most manufacturers. Optional is the possibility of connecting a modem, so that even in a complete power failure or the management of the connected nodes is possible.
Related to console servers are KVM-over- IP devices that promote rather than serial KVM signals over IP. For OOB category also includes remote-controlled socket strips (English: remote power ) that can be connected either in series or via Ethernet.
In the early days of the console server manufacturers such as Cisco or Xyplex related proprietary operating systems. Today has established itself in most devices embedded Linux as the operating system. Probably the first manufacturer was Cyclades, which was bought in 2006 by Avocent. Problem were places GPL license violations.
Designation
The predecessors of the console servers were so-called terminal server. Now, as then Terminal Server are more end-user, that is, users at that time were over serial lines - today via LAN - connected to a central, powerful server on which they are working. Therefore has evolved over time, the term console servers and established. The first equipment that had this name, the "System Console Switch " (1996 ) and the "Console Server 3200 " were (1998 ) from Lightwave Communications.