The Lines version 1.0:

M-Line:
Server line, the format is als following:
M:servername.raptornet.org:serverip:Server Description:9998:servernumeric

A-Line:
Admin line, the format is as follows:
A:Server Description:Raptornet Server:Nick_Admin <email@address>::

Y-Lines:
Connect Classes, for incoming and outgoing. That mean Server an Client lines. This are the Raptornet Server and Client lines:
Server:
Y:30:90:300:1:4000000
Clients:
Y:10:90::900:512000:2:32
Opers:
Y:14:90::100:512000:3.3:3.3

I-Lines:
To allow clients to connect, they need authorization. This can be done based on hostmask, address mask, and/or with a password. With intelligent use of classes and the maxconnections field in the Y: lines, you can let in a specific domain, but get rid of all other domains in the same toplevel, thus setting up some sort of 'reverse K: line'.
I:<IP mask or crap to force resolving>:<opt passwd>:<hostmask>::<class>
To allow everyone put this line in your config file:
I:*@*::*@*::10

T-Lines:
It is possible to show a different Message of the Day to a connecting client depending on its origin.
T:<hostmask>:<path to motd file>
DPATH/net_com.motd contains a special MOTD where users are encouraged to register their domains and get their own I: lines if they're in Europe, or move to US.UnderNet.org if they're in the USA.
T:*.net:net_com.motd
T:*.com:net_com.motd
A different MOTD for ourselves, where we point out that the helpdesk better not be bothered with questions regarding irc...
T:*.london.ac.uk:london.motd

K-Lines:
While running your server, you will most probably encounter individuals or groups of persons that you do not wish to have access to your server. For this purpose, the ircd understands "kill lines".
K:<host/IP mask>:"<opt reason>":<username mask>
It is possible to use a file as comment for the ban.
K:<host/IP mask>:!<path to file>:<usermask>
The default reason is: "You are banned from this server" Note that K: lines are local to the server; if you ban a person or a whole domain from your server, they can get on IRC via any other server that doesn't have them K: lined (yet). With a simple comment, using quotes:
K:*.au:"Please use a nearer server":*
K:*.edu:"Please use a nearer server":*
With a file, prepending a '!' before the filename. The file can contain for example, a reason, a link to the server rules and a contact address.
K:unixbox.flooder.co.uk:!kline/youflooded.txt:*luser
Additionally, you may specify a hostmask prefixed with $R to indicate a match should be performed against the "real-name" / "info" field instead of the host or IP.
K:$R*sub7*:"You are infected with a Trojan":*

IP-based kill lines are designated with a lowercase 'k'. These lines use the same format as normal K: lines, except they apply to all hosts, even if an IP address has a properly resolving host name.
k:192.168.*:!klines/martians:*

R-Lines [obsoleted]:
A more flexible way of restricting access to your server is the use of "restriction lines". These tell the server to start up an (external) program, upon whose output is decided whether the client is allowed access. The program should print "Y" or "N <reason>" on its stdout. Note that the use of R: lines is discouraged and deprecated, needs a compile-time define, eats CPU cycles and may well be taken out in future releases of ircd.
R:<host/IP mask>:<program name>:<username mask>
(a good example is a perl script that checks certain things)

C/N-Lines:
This are link lines.The format of the lines is as follows
C:<remote hostname or IP>:<password>:<remote server name>:<port>:<class>
N:<remote hostname or IP>:<password>:<remote server name>:<hostmask>:<class>
Hostmask is optional. The class has to be an Y-line.

H-Lines:
If your server starts on a bit larger network, you'll probably get assigned one or two uplinks to which your server can connect. If your uplink(s) also connect to other servers than yours (which is probable), you need to define your uplink as being allowed to "hub".
H:<allowed hostmask>::<server name>
Example:
H:*::hub.raptornet.org::

L-Line:
Of course, the opposite is also possible: forcing a server to be a leaf. L: lines follow Murphy's Law: if you use them, there's a big chance that routing will be screwed up afterwards.
L:<opt disallowed hostmask>::<server mask>:<opt max depth>

D-Line:
For an advanced, real-time rule-based routing decision making system you can use Disallow lines. For more information, see doc/readme.crules.
D:<server mask that ircd will refuse to connect to>::<rule>
d:<server mask that ircd will not autoconnect to>::<rule>
D:*.US.UnderNet.org::connected(*.US.UnderNet.org)
d:*.EU.UnderNet.org::connected(Amsterdam.NL.EU.*)
The following line is recommended for leaf servers:
d:*::directcon(*)

O/o-Lines:
Irc Operator lines O is Global Operator o is local operator.
O:<host/IP mask>:<encrypted password>:<Nick>:<Oflags>:<connection class>
o:<host/IP mask>:<encrypted password>:<Nick>:<Oflags>:<connection class>

P-Lines:
Port lines, on which port your users can connect to:
P:<hostmask, or path>:::<client port number>
P::::6667
P::::6668
P:*.nl:::6666
P:/tmp/.ircd:::6667

S-Lines:
Socks exception. These IP addresses are the ones that have exception from the socks/proxy detector that the ircd has. Note, that you can only use IP addresses, and not hostmasks, since the socks/proxy detector is checking before the user have registered themselfes.
If you want password protection on this - use I:lines for it.
S:127.0.0.1:::

U-Lines:
U line gives a server the power to change modes that will effect on every server. Mostly used for services. The best way to use it to give every hub server an U line.
U:hub.server.org::*

V-lines:
This is a line that can change hostmasks or ips of users into fake hosts.
V:originalhost::newfakehost

Q-lines:
With this line you can block off nicknames. Only an ircop can use the nickname. Or a service.
Q::reason:nickname

Author: Cable-Dude January 5th 2001