Console server
A console server ( English : Console Server ) is a remote maintenance component and is used for management of computer network nodes that are likely to be found in the data center, such as ( Unix -) servers, routers , switches , firewalls , PBXs , UPSs . The nodes to be connected only require a serial interface .
The purpose of the console server is to guarantee the operability of the connected nodes even if the node or the computer network ( LAN ) fails . Using the serial console, it is then still possible to remotely carry out emergency maintenance on a network component, for example, or to reconfigure the network interface on a server. Since the last section to the node does not take place via the LAN, i.e. in-band, it is also referred to as out-of-band management, or OOB for short. For reasons of availability and security, it is advisable to connect the console server to a dedicated management network.
functionality
A console server has up to 48 serial ports and at least one Ethernet port that makes the serial interfaces of the nodes available via TCP . Some console servers also have a built-in modem , ISDN cards or the option of retrofitting, e.g. B. via USB or PCMCIA .
Most console servers offer a FIFO buffer (First in First out) as a first aid, which temporarily stores the last messages from the device to be monitored. With the help of this stored information, the cause of an error can be identified and solved more easily. Some manufacturers of console servers offer pattern recognition that can trigger an alarm on strings like "Panic" or "Ok" on the console ( e-mail , SNMP , SNMP traps).
Standards
Encrypted access to the console server via Secure Shell (SSH) and the connected nodes is now mandatory. In addition to local authentication, authentication via remote services such as RADIUS , LDAP , or TACACS + is useful or common with multiple console servers . In addition, most manufacturers allow both the configuration of the console server and access to the connected nodes via a convenient web interface. There is also the option of connecting a modem, so that the connected nodes can still be managed even in the event of a complete power failure.
KVM-over-IP devices are related to console servers , which transport KVM signals over IP instead of serial KVM signals. The OOB category also includes remote-switchable socket strips ( remote power ) that can be connected either serially or via Ethernet.
In the early days of console servers, manufacturers such as Cisco or Xyplex used proprietary operating systems . Nowadays, embedded Linux has established itself as the operating system in most devices . The first manufacturer was probably Cyclades, which was bought by Avocent in 2006 . GPL license violations were problematic in places .
designation
The predecessors of the console servers were so-called terminal servers . Today, as then, terminal servers are more of an end-user device, which means that users were connected to a central, high-performance server on which they work via serial lines - today via LAN . This is why the term console server has emerged and established itself over time. The first devices to bear this name were the "System Console Switch" (1996) and the "Console Server 3200" (1998) from Lightwave Communications.
Web links
Individual evidence
- ↑ Page no longer available , search in web archives: Acquisition of Cyclades
- ↑ Golem charges GPL violation
- ↑ Difference between terminal and console servers