Software:BNC
A BNC (short for Bounced Network Connection) is a piece of software that is used to relay traffic and connections in computer networks, much like a proxy. Using a BNC allows a user to hide the original source of the user's connection, providing privacy as well as the ability to route traffic through a specific location. A BNC can also be used to hide the true target to which a user connects.[1]
IRC

One common usage is over Internet Relay Chat (IRC) via a BNC running on remote servers. In such an environment, where it is very easy to ascertain a user's IP address a BNC may help to hide the original connection source, as well as providing the opportunity for "vhosts" or "virtual hosts". The use of a vhost does not conceal the connection any better but merely adds a statement as the hostname.
Many BNCs remain connected to an IRC server in the event the client should disconnect from the Internet. Often state changes are tracked so that they may be relayed to the client upon reconnection. Some implementations opt to store all messages sent across the network that the client would have normally received and send them upon the client's reconnection; this is often considered to be much too resource dependent for commercial hosting services to provide. Other logging features and bot like functions may be included with various implementations but are not standard.
Example
- User A logs onto IRC directly and appears as
USER!user@users.reverse.dns - User A logs onto IRC indirectly through a BNC and appears as
USER!user@bnc.net
Software
A list of bouncer software.
- Bip IRC Proxy maintains a persistent connection and shows a backlog on reconnect.[2]
- bnc is the original IRC bouncer.[3]
- ezbounce's features include password protection, remote administration, logging and listening on multiple ports.[3]
- JBouncer for IRC, written in Java. Supports logging.[4]
- muh bnc is a smart and versatile irc-bouncing tool that will also go on IRC as soon as it is launched, guarding or attempting to get one's nick.[3]
- psyBNC is said to be the oldest and most well-known IRC bouncer.[1] It is easy to use, runs on Linux[5] and became popular on FreeBSD,[6] supports IPv4, IPv6, SSL, logging, multiple users and networks etc. Although psyBNC is like any other IRC proxy, it is often installed on compromised systems by the attacker.[7]
- shroudBNC (IRC) supports SSL connections and offers a web interface. [8]