A bouncer (short: BNC ) in IRC is a program that can mediate between an IRC client and an IRC server and thus works as a proxy .
The main goal of most bouncers, however, is not the pure mediation between a client and a server, but rather to maintain a permanent connection to an IRC server or one or more IRC networks . Since in many IRC networks privileges in channels are lost after logging out and the nickname can be used by anyone else, the only way to "reserve" a nickname or channel privileges is to stay logged in practically permanently with the help of the bouncer. For this reason, bouncer programs usually run on a server on the Internet. The user no longer has to be permanently online when using the bouncer.
Other reasons for using bouncers are:
- Protection of the client computer from attacks, e.g. B. a DoS attack or the application of exploits . Since from the point of view of the IRC server and thus the users in the IRC only know the IP address of the bouncer host name, attacks are only directed against this.
- To appear on IRC with a different DNS name (namely that of the bouncer host ), which - beyond the purely technical necessity - makes a certain sense, e.g. B. a funny, strange or light text. Providers of rentable bouncers often have a large selection of such DNS names , between which the tenant can usually switch at any time and as often as desired.
- The indirect establishment of a connection to the server if the direct connection is not possible due to a restrictive firewall or similar.
- the establishment of an encrypted connection from public networks (e.g. WLANs), as many IRC networks do not offer their own SSL servers due to capacity problems.
- Keeping DCC connections. Since the connection between the bouncer and client is established here, a bouncer user can go offline while his bouncer maintains the DCC connection.
- Intermediate storage of channel and private messages when absent.
- Anonymity. Since the IP address is usually hidden behind the bouncer, the chatter cannot be traced directly.
More sophisticated bouncers offer various extras, for example the automatic "defense" of the nicks and channels from strangers or the distribution of the channel operator status (ChanOP) to familiar users, a party line (IRC server independent chat only between the users of a bouncer ), automatic change to the most advantageous server within an IRC network and many others.
There are different bouncer programs, which mainly differ in their features. The following is an incomplete list. All programs listed are open source .
- ezbounce is a bouncer that supports SSL-encrypted connections, IPv6 and chat logs.
- psyBNC is a bouncer that supports symmetrically encrypted calls, SSL-encrypted connections, the recording of queries in the absence of the user and IPv6. You can connect several psyBNC instances to a "botnet" with a common party line. psyBNC can be expanded with its own scripting language.
- shroudBNC (sBNC) supports SSL-encrypted connections and has a web interface. sBNC records queries when the user is absent. sBNC can be expanded with Tcl scripts and modules in C ++; some ready-made Tcl scripts are also included in the source package.
- ZNC is another bouncer. It also supports SSL-encrypted connections and has a web interface. ZNC can be explained by (existing) modules and scripts in Perl greatly expand and Tcl, supports IPv6 and can channel log.
Criticism of bouncers
Bouncers enforce various behaviors that are not welcome in some IRC networks (this list relates to the range of functions and use of most bouncers):
- Networks that do not offer the possibility of registering nicks and channels often do so consciously from the stance that nicks and channels are in principle free, i.e. no user has a permanent right to use a particular nick or channel. Bouncers, however, strive to counter this principle by keeping nicks and channels free for their "owner" through permanent presence.
- In networks with IRC services that enable the registration of nicks and channels, the corresponding protective functions of the bouncers are largely superfluous and can unnecessarily burden the network through senseless battles with IRC services.
- Bouncers reinforce the impression of idling on IRC, since users who are offline are still kept present by their bouncer, but are not active. This sometimes makes it difficult to tell when a user is actually there or is only represented by his bouncer.
- In general, like all unguarded bots on IRC, bouncers carry the risk of behaving in an uncontrolled manner in the absence of the owner without it being noticed and prevented in time.
- IRC-Mania.de - Detailed information about the utility of a bouncer on IRC.
- IRC-Guide.de - Detailed information about bouncers, from the function to the installation to the setup