Tonight I've been looking into ways to set up a local chat system for
students in one of my courses.  My initial thought was to use the
NetKit `talk` at `talkd` programs, but I couldn't find an active
homepage.  Maybe they are so mature that noone needs to touch the
code, but I expect they are actually just quietly dying in the corners
of assorted harddrives, without any users to love them.

Since part of the goal of my course is to get the students up to speed
on common open source development tools, my next thought was to go
with a local [IRC][] server.  I know that there many wonderful public
IRC servers (e.g. [freenode][]), but why use a free service when you
can run the service locally?  Anyhow, here's my setup.

Local IRC server
================

There seem to be a number of these out there.  I chose [ngIRCd][],
because it's packaged for Gentoo (`net-irc/ngircd`), and it seems to
be both cleanly coded and actively maintained (in [[Git]] ☺).
Installation was a simple:

    # emerge -av ngircd
    # emacs /etc/ngircd/ngircd.conf
    # cat /etc/ngircd/ngircd.conf
    [Global]
        Name = irc.example.com
        AdminInfo1 = John Doe
        AdminInfo2 = 123 Street Rd.
        AdminEMail = jdoe@example.com
        Info = bla bla bla
        ServerGID = nogroup
        ServerUID = ngircd
    [Options]
        PAM = no
    # /etc/init.d/ngircd restart

I didn't add `ngircd` to the default runlevel.  I'll just start it by
hand whenever I want to use it.

Local connections
=================

Using the excellent [[irssi]] client (`net-irc/irssi` on Gentoo):

    $ irssi -c localhost

When you specify a server on the command line with `-c server`,
`irssi` won't connect to any other servers for which you've configured
automatic connection.  In my case, this is what I want.

Exposing the IRC server on a remote host
========================================

Alright, I've got an IRC server running on my laptop, but I'm behind a
firewall.  I can expose my IRC server to the students by forwarding
the IRC port to our department server, where the students all have
shell accounts.

    $ ssh -R localhost:6667:localhost:6667 physics.uni.edu

If someone else is already using port 6667 on the department server,
it's easy to use another one:

    $ ssh -R localhost:6668:localhost:6667 physics.uni.edu

Students can then connect by [[SSHing|SSH]] into the department server
and running `irssi` there:

    student@home $ ssh physics.uni.edu
    student@physics $ irssi -c localhost -p 6668

And that's all there is too it!  An easy way to introduce people to a
popular tool.

[IRC]: http://en.wikipedia.org/wiki/Internet_Relay_Chat
[freenode]: http://freenode.net/
[ngIRCd]: http://ngircd.barton.de/

[[!tag tags/web]]
[[!tag tags/tools]]