Proxy IRC client and ICB server
You probably know what IRC
is, but ICB?
icb, n. Internet citizen's band,
an obscure teleconferencing system used primarily by alumni of
(also called Internet CB or International CB)
ICBIRC(8) OpenBSD System Manager's Manual ICBIRC(8)
icbirc - proxy IRC client and ICB server
icbirc [-d] [-l listen-address] [-p listen-port] [-s server-name] [-P
icbirc is a proxy that allows to connect an IRC client to an ICB server.
The proxy accepts client connections, connects to the server, and for-
wards data between those two connections.
Commands from the IRC client are translated to ICB commands and forwarded
to the ICB server. Messages from the ICB server are translated to IRC
messages and forwarded to the IRC client.
The options are as follows:
-d Do not daemonize (detach from controlling terminal)
and produce debugging output on stdout/stderr.
-l listen-address Bind to the specified address when listening for
client connections. If not specified, connections to
any address are accepted.
-p listen-port Bind to the specified port when listening for client
connections. Defaults to 6667 when not specified.
-s server-name Hostname or numerical address of the ICB server to
-P server-port Port of the ICB server to connect to. Defaults to
7326 when not specified.
$ icbirc -s default.icb.net
IRC (Internet Relay Chat) and ICB (Internet Citizen's Band) are two sepa-
rate chat protocols. ICB is an older and simpler protocol, basically a
subset of IRC. The two most significant differences (from the client's
An ICB client can only join a single channel (called group). Joining a
second channel automatically parts the first channel.
An ICB channel can only have a single operator (called moderator). Giv-
ing operator status to a second client automatically removes operator
status from the first client.
icbirc supports the following IRC commands:
PASS Set the default group, used during login.
NICK Set or change nickname.
USER Supply additional user information (like ident), used dur-
LIST List all groups.
WHOIS Shows information about a user.
WHO Lists matching users. Arguments starting with '#' are in-
terpreted as channel names (listing all users in the speci-
fied channel), anything else is used for a simple string
search within users' 'nick!ident@host'.
JOIN Join a group.
PRIVMSG Send an open or personal message.
NOTICE Same as PRIVMSG.
TOPIC Set group topic.
KICK nick Boot nick from group.
MODE +o nick Pass moderation to nick.
QUIT Close client and server connection, wait for next client
Additionally, the command RAWICB can be used to send custom ICB commands.
The proxy automatically prefixes the correct command length and replaces
commas with ICB argument separators. For example:
RAWICB hm,nick,msg Send msg to nick.
Internet Relay Chat Protocol, RFC 1459.
Internet Relay Chat: Client Protocol, RFC 2812.
Internet Relay Chat: Channel Management, RFC 2811.
ICB Protocol, ftp://ftp.icb.net/pub/icb/src/icbd/Protocol.html.
The History of ICB, http://www.icb.net/history.html.
General guide to Netiquette on ICB,
The first version of icbirc was written in 2003.
Daniel Hartmeier <email@example.com>
ICB is not IRC. Depending on the ICB community on a particular server,
netiquette rules vary greatly from common IRC rules (or lack thereof).
Client scripts or other forms of automated client actions might generate
noise or violate ICB community policies, and lacking support for some
commands might confuse the script. Clients should be properly configured
and tested on a dedicated server before connecting to a public server.
In particular, WHOIS and WHO filtering is done on the proxy. Each such
request causes the proxy to fetch the entire user list from the ICB serv-
er (there are no ICB commands that take filters), hence automatic WHOIS
requests from the IRC client can cause unwanted load on the ICB server
(turn off 'WHOIS on JOIN' in the IRC client, if enabled).
On ICB, a moderator (channel operator) can leave the group (channel) and
rejoin later, preserving his status, as compared to IRC, where the chan-
nel would be left operator-less in this case. The proxy does not cur-
rently detect the operator status on rejoin in this case, and the IRC
client will (temporarily) show the channel op-less.
IPv6 is not supported yet.
OpenBSD 3.4 Aug 6, 2003 3
There are many IRC clients, I myself like xchat.
The whole point of the proxy is that you can use whatever client you like.
Tested with xchat, ircII, BitchX and mIRC. irssi works, too, with option lag_max_before_disconnect 0.
BSD license applies.
2.1: Apr 25, 2016
Return *** as nick in IRC error messages (where missing),
add pledge(2) call on OpenBSD,
2.0: Aug 21, 2015
Merge OpenBSD port patches, originally from ray@ in 2009:
Fix corruption that occurs when connecting and reconnecting to
icbirc repeatedly. After a while, icbirc starts reusing the command
buffer from a previous connection, causing all further connections
to incorrectly parse commands.
1.9: Aug 20, 2015
When receiving an IRC PING, additionally send an ICB NOOP, to detect
a stalled server connection. Patch from Sebastien Marie <firstname.lastname@example.org>.