struct Channel: add mode_lock structure to the channel object.

[irc/rqf/shadowircd.git] / doc / technical / ts6-protocol.txt

TS6 protocol description
Written by Jilles Tjoelker

General format: much like rfc1459
Maximum parameters for a command: 15 (this does not include the prefix
and command name)

SID: a server's unique ID. It is configured in each server and consists of
a digit and two alphanumerics. Sending SIDs with lowercase letters is
questionable.

UID: a client's unique ID. It consists of the server's SID and six
alphanumerics (so it is nine characters long). The first of the alphanumerics
should be a letter, numbers are legal but reserved for future use.

hunted: a parameter type used for various remote requests. From local users,
nicknames and server names are accepted, possibly with wildcards; from servers,
UIDs/SIDs (sending names or even wildcards is deprecated). This is done with
the function hunt_server(). Any rate limiting should be done locally.

duration: a parameter type used for ban durations. It is a duration in seconds.
A value of 0 means a permanent ban.

propagation: to which other servers the command is sent

For all commands with a hunted parameter, the propagation is determined by
that, and not otherwise specified.

For all commands with a target server mask parameter, the propagation is
determined by that, and not otherwise specified. The command is sent to all
servers with names matching the given mask (for example '*', '*.example.com',
'irc.example.com'). Those servers do not have to be directly connected.
Targets cannot be SIDs.

Propagation broadcast means the command is sent to all servers.

Propagation one-to-one means the command is only sent to the target or the
server the target is on.

Propagation none means the command is never sent to another server if it is
received.

For some other commands, the propagation depends on the parameters and is
described in text.

services server: server mentioned in a service{} block. There are no services
servers on EFnet.

service: client with umode +S. This implies that it is on a services server.

connection setup:
The initiator sends the PASS, CAPAB and SERVER messages. Upon receiving the
SERVER, the listener will check the information, and if it is valid, it will
send its own PASS, CAPAB and SERVER messages, followed by SVINFO and the burst.
Upon receiving the SERVER, the initiator will send SVINFO and the burst. If
ziplinks are used, SVINFO is the first compressed message.

The burst consists of SID and SERVER messages for all known servers, BAN
messages for all propagated bans, UID or EUID messages for all known users
(possibly followed by ENCAP REALHOST, ENCAP LOGIN and/or AWAY) and SJOIN
messages for all known channels (possibly followed by BMASK and/or TB).

user modes:
(all)
+D (deaf: does not receive channel messages)
+S (network service) (only settable on burst from a services server)
+a (appears as server administrator)
+i (invisible, see rfc1459)
+o (IRC operator, see rfc1459)
+w (wallops, see rfc1459) (always propagated for historical reasons)
(charybdis TS6)
+Q/+R/+g/+l/+s/+z (only locally effective)
+Z (ssl user) (only settable on burst)
possibly more added by modules

channel modes:
(all)
statuses
+o (prefix @) (ops)
+v (prefix +) (voice)
type A
+b (ban)
+e (ban exception) (capab: EX)
+I (invite exception) (capab: IE)
type B
+k (key: password required to join, <= 23 ascii chars, no : or , or whitespace)
type C
+l (limit: maximum number of members before further joins are disallowed)
type D
+m (moderated)
+n (no external messages)
+p (private: does not appear in /whois to non-members, no /knock allowed)
+r (only registered users may join) (only if a services server exists) (capab: SERVICES)
+s (secret)
+t (only chanops may change topic)
(charybdis TS6)
type A
+q (quiet)
type C
+f (forward: channel name <= 30 chars)
+j (join throttle: N:T with integer N and T)
type D
+F (free target for +f)
+L (large ban list)
+P (permanent: does not disappear when empty)
+Q (ignore forwards to this)
+c (strip colours)
+g (allow any member to /invite)
+z (send messages blocked by +m to chanops)

<numeric>
source: server
parameters: target, any...

The command name should be three decimal ASCII digits.

Propagates a "numeric" command reply, such as from a remote WHOIS request.

If the first digit is 0 (indicating a reply about the local connection), it
should be changed to 1 before propagation or sending to a user.

Numerics to the local server may be sent to opers.

To avoid infinite loops, servers should not send any replies to numerics.

The target can be:
- a client
  propagation: one-to-one
- a channel name
  propagation: all servers with -D users on the channel

Numerics to channels are broken in some older servers.

ADMIN
source: user
parameters: hunted

Remote ADMIN request.

AWAY
source: user
propagation: broadcast
parameters: opt. away reason

If the away reason is empty or not present, mark the user as not away.
Otherwise, mark the user as away.

Changing away reason from one non-empty string to another non-empty string
may not be propagated.

BAN
charybdis TS6
capab: BAN
source: any
propagation: broadcast (restricted)
parameters: type, user mask, host mask, creation TS, duration, lifetime, oper, reason

Propagates a network wide ban.

The type is K for K:lines, R for resvs and X for X:lines; other types are
reserved. The user mask field is only used for K:lines; for resvs and X:lines
the field is ignored in input and sent as an asterisk.

The creation TS indicates when this ban was last modified. An incoming ban MUST
be ignored and not propagated if the creation TS is older than the creation TS
of the current ban. If the ban is identical, it SHOULD NOT be propagated to
avoid unnecessary network traffic. (Two changes to bans that set the TS to the
same value may cause desynchronization.)

The duration is 0 for an unban and relative to the creation TS for a ban.
When the duration has passed, the ban is no longer active but it may still
be necessary to remember it.

The lifetime is relative to the creation TS and indicates for how long this
ban needs to be remembered and propagated. This MUST be at least the duration.
Initially, it is usually set the same as the duration but when the ban is
modified later, it SHOULD be set such that the modified ban is remembered at
least as long as the original ban. This ensures that the original ban does not
revive via split servers. This requirement is only a SHOULD to allow for
implementations that only inject bans and do not remember any; implementations
that remember and propagate bans MUST set the lifetime appropriately.

The oper field indicates the oper that originally set the ban. If this message
is the initial propagation of a change, it SHOULD be sent as * (an asterisk).

The reason field indicates the reason for the ban. Any part after a | (vertical
bar) MUST NOT be shown to normal users. The rest of the field and the creation
TS and duration MAY be shown to normal users.

BMASK
source: server
propagation: broadcast
parameters: channelTS, channel, type, space separated masks

If the channelTS in the message is greater (newer) than the current TS of
the channel, drop the message and do not propagate it.

Type is the mode letter of a ban-like mode. In efnet TS6 this is 'b', 'e' or
'I'. In charybdis TS6 additionally 'q' is possible.

Add all the masks to the given list of the channel.

All ban-like modes must be bursted using this command, not using MODE or TMODE.

CAPAB
source: unregistered server
propagation: none
parameters: space separated capability list

Sends capabilities of the server. This must include QS and ENCAP. It is also
strongly recommended to include EX, CHW, IE and KNOCK, and for charybdis TS6
also SAVE and EUID. For use with services, SERVICES and RSFNC are strongly
recommended.

The capabilities may depend on the configuration for the server they are sent
to.

CHGHOST
charybdis TS6
source: any
propagation: broadcast
parameters: client, new hostname

Changes the visible hostname of a client.

Opers are notified unless the source is a server or a service.

CONNECT
source: any
parameters: server to connect to, port, hunted

Remote connect request. A server WALLOPS should be sent by the receiving
server.

The port can be 0 for the default port.

DLINE
charybdis TS6
encap only
source: user
parameters: duration, mask, reason

Sets a D:line (IP ban checked directly after accepting connection).

The mask must be an IP address or CIDR mask.

ENCAP
source: any
parameters: target server mask, subcommand, opt. parameters...

Sends a command to matching servers. Propagation is independent of
understanding the subcommand.

Subcommands are listed elsewhere with "encap only".

ERROR
source: server or unregistered server
propagation: none
parameters: error message

Reports a (usually fatal) error with the connection.

Error messages may contain IP addresses and have a negative effect on server
IP hiding.

ETRACE
encap only
encap target: single server
source: oper
parameters: client

Remote ETRACE information request.

EUID
charybdis TS6
capab: EUID
source: server
parameters: nickname, hopcount, nickTS, umodes, username, visible hostname, IP address, UID, real hostname, account name, gecos
propagation: broadcast

Introduces a client. The client is on the source server of this command.

The account name is '0' if the user is not logged in with services.

Nick TS rules apply.

EUID is similar to UID but includes the ENCAP REALHOST and ENCAP LOGIN
information.

GCAP
encap only
encap target: *
source: server
parameters: space separated capability list

Capability list of remote server.

GLINE
efnet TS6
capab: GLN
source: user
parameters: user mask, host mask, reason
propagation: broadcast

Propagates a G:line vote. Once votes from three different opers (based on
user@host mask) on three different servers have arrived, trigger the G:line.
Pending G:lines expire after some time, usually ten minutes. Triggered G:lines
expire after a configured time which may differ across servers.

Requests from server connections must be propagated, unless they are found to
be syntactically invalid (e.g. '!' in user mask). Therefore, disabling glines
must not affect propagation, and too wide glines, double votes and glines that
already exist locally must still be propagated.

Of course, servers are free to reject gline requests from their own operators.

GUNGLINE
efnet TS6
encap only
encap target: *
source: user
parameters: user mask, host mask, reason
propagation: broadcast

Propagates a G:line removal vote. Once three votes have arrived (as with
G:lines), remove the G:line. Pending G:lines removals expire after some time,
usually ten minutes.

Pending G:line removals do not interact with pending G:lines. Triggering a
G:line does not affect a pending G:line removal. Triggering a G:line removal
does not affect a pending G:line.

INFO
source: user
parameters: hunted

Remote INFO request.

INVITE
source: user
parameters: target user, channel, opt. channelTS
propagation: one-to-one

Invites a user to a channel.

If the channelTS is greater (newer) than the current TS of the channel, drop
the message.

Not sending the channelTS parameter is deprecated.

JOIN
1.
source: user
parameters: '0' (one ASCII zero)
propagation: broadcast

Parts the source user from all channels.

2.
source: user
parameters: channelTS, channel, '+' (a plus sign)
propagation: broadcast

Joins the source user to the given channel. If the channel does not exist yet,
it is created with the given channelTS and no modes. If the channel already
exists and has a greater (newer) TS, wipe all simple modes and statuses and
change the TS, notifying local users of this but not servers (note that
ban-like modes remain intact; invites may or may not be cleared).

A JOIN is propagated with the new TS of the channel.

KICK
source: any
parameters: channel, target user, opt. reason
propagation: broadcast

Kicks the target user from the given channel.

Unless the channel's TS is 0, no check is done whether the source user has ops.

Not sending the reason parameter is questionable.

KILL
source: any
parameters: target user, path
propagation: broadcast

Removes the user from the network.

The format of the path parameter is some sort of description of the source of
the kill followed by a space and a parenthesized reason. To avoid overflow,
it is recommended not to add anything to the path.

KLINE
1.
encap only
source: user
parameters: duration, user mask, host mask, reason

Sets a K:line (ban on user@host).

2.
capab: KLN
source: user
parameters: target server mask, duration, user mask, host mask, reason

As form 1, deprecated.

KNOCK
capab: KNOCK
source: user
parameters: channel
propagation: broadcast

Requests an invite to a channel that is locked somehow (+ikl). Notifies all
operators of the channel. (In charybdis, on +g channels all members are
notified.)

This is broadcast so that each server can store when KNOCK was used last on
a channel.

LINKS
source: user
parameters: hunted, server mask

Remote LINKS request. The server mask limits which servers are listed.

LOCOPS
1.
encap only
source: user
parameters: text

Sends a message to operators (with umode +l set). This is intended to be
used for strict subsets of the network.

2.
capab: CLUSTER
source: user
parameters: target server mask, text

As form 1, deprecated.

LOGIN
encap only
source: user
parameters: account name

In a burst, states that the source user is logged in as the account.

LUSERS
source: user
parameters: server mask, hunted

Remote LUSERS request. Most servers ignore the server mask, treating it as '*'.

MODE
1.
source: user
parameters: client, umode changes
propagation: broadcast

Propagates a user mode change. The client parameter must refer to the same user
as the source.

Not all umodes are propagated to other servers.

2.
source: any
parameters: channel, cmode changes, opt. cmode parameters...

Propagates a channel mode change.

This is deprecated because the channelTS is not included. If it is received,
it should be propagated as TMODE.

MOTD
source: user
parameters: hunted

Remote MOTD request.

NICK
1.
source: user
parameters: new nickname, new nickTS
propagation: broadcast

Propagates a nick change.

2.
source: server
parameters: nickname, hopcount, nickTS, umodes, username, hostname, server, gecos

Historic TS5 user introduction. The user is on the server indicated by the
server parameter; the source server is meaningless (local link).

NICKDELAY
charybdis TS6
encap only
encap target: *
source: services server
parameters: duration, nickname

If duration is greater than 0, makes the given nickname unavailable for that
time.

If duration is 0, removes a nick delay entry for the given nickname.

There may or may not be a client with the given nickname; this does not affect
the operation.

NOTICE
source: any
parameters: msgtarget, message

As PRIVMSG, except NOTICE messages are sent out, server sources are permitted
and most error messages are suppressed.

Servers may not send '$$', '$#' and opers@server notices. Older servers may
not allow servers to send to specific statuses on a channel.

OPERSPY
encap only
encap target: *
source: user
parameters: command name, parameters

Reports operspy usage.

OPERWALL
source: user
parameters: message
propagation: broadcast

Sends a message to operators (with umode +z set).

PART
source: user
parameters: comma separated channel list, message

Parts the source user from the given channels.

PASS
source: unregistered server
parameters: password, 'TS', TS version, SID

Sends the server link password, TS version and SID.

PING
source: any
parameters: origin, opt. destination server

Sends a PING to the destination server, which will reply with a PONG. If the
destination server parameter is not present, the server receiving the message
must reply.

The origin field is not used in the server protocol. It is sent as the name
(not UID/SID) of the source.

Remote PINGs are used for end-of-burst detection, therefore all servers must
implement them.

PONG
source: server
parameters: origin, destination

Routes a PONG back to the destination that originally sent the PING.

PRIVMSG
source: user
parameters: msgtarget, message

Sends a normal message (PRIVMSG) to the given target.

The target can be:
- a client
  propagation: one-to-one
- a channel name
  propagation: all servers with -D users on the channel
  (cmode +m/+n should be checked everywhere, bans should not be checked
  remotely)
- a status character ('@'/'+') followed by a channel name, to send to users
  with that status or higher only.
  capab: CHW
  propagation: all servers with -D users with appropriate status
- '=' followed by a channel name, to send to chanops only, for cmode +z.
  capab: CHW and EOPMOD
  propagation: all servers with -D chanops
- a user@server message, to send to users on a specific server. The exact
  meaning of the part before the '@' is not prescribed, except that "opers"
  allows IRC operators to send to all IRC operators on the server in an
  unspecified format.
  propagation: one-to-one
- a message to all users on server names matching a mask ('$$' followed by mask)
  propagation: broadcast
  Only allowed to IRC operators.
- a message to all users with hostnames matching a mask ('$#' followed by mask).
  Note that this is often implemented poorly.
  propagation: broadcast
  Only allowed to IRC operators.

In charybdis TS6, services may send to any channel and to statuses on any
channel.

PRIVS
charybdis TS6
encap only
encap target: single server
source: oper
parameters: client

Remote PRIVS information request.

QUIT
source: user
parameters: comment

Propagates quitting of a client. No QUIT should be sent for a client that
has been removed as result of a KILL message.

REALHOST
charybdis TS6
encap only
encap target: *
source: user
parameters: real hostname

In a burst, propagates the real host of a dynamically-spoofed user.

REHASH
charybdis TS6
encap only
source: user
parameters: opt. rehash type

Remote REHASH request. If the rehash type is omitted, it is equivalent to
a regular /rehash, otherwise it is equivalent to /rehash <rehash type>.

RESV
1.
encap only
source: user
parameters: duration, mask, reason

Sets a RESV, making a nickname mask or exact channel unavailable.

2.
capab: CLUSTER
source: user
parameters: target server mask, duration, mask, reason

As form 1, deprecated.

RSFNC
encap only
capab: RSFNC
encap target: single server
source: services server
parameters: target user, new nickname, old nickTS, new nickTS

Forces a nickname change and propagates it.

The command is ignored if the nick TS of the user is not equal to the old
nickTS parameter. If the new nickname already exists (and is not the target
user), it is killed first.

SASL
charybdis TS6
encap only
1.
encap target: *
source: server
parameters: source uid, '*', 'S', sasl mechanism name

Requests that a SASL agent (a service) initiate the authentication process.
The source uid is that of an unregistered client. This is why it is not sent
as the prefix.

2.
encap target: single server
source: server
parameters: source uid, target uid, mode, data

Part of a SASL authentication exchange. The mode is 'C' to send some data
(base64 encoded), or 'S' to end the exchange (data indicates type of
termination: 'A' for abort, 'F' for authentication failure, 'S' for
authentication success).

SAVE
capab: SAVE
source: server
propagation: broadcast
parameters: target uid, TS

Resolve a nick collision by changing a nickname to the UID.

The server should verify that the UID belongs to a registered user, the user
does not already have their UID as their nick and the TS matches the user's
nickTS. If not, drop the message.

SAVE should be propagated as a regular NICK change to links without SAVE capab.
present.

SERVER
1.
source: unregistered server
parameters: server name, hopcount, server description

Registers the connection as a server. PASS and CAPAB must have been sent
before, SVINFO should be sent afterwards.

If there is no such server configured or authentication failed, the connection
should be dropped.

This is propagated as a SID message.

2.
source: server
propagation: broadcast
parameters: server name, hopcount, server description

Introduces a new TS5 server, directly connected to the source of this command.
This is only used for jupes as TS5 servers may do little else than existing.

SID
source: server
propagation: broadcast
parameters: server name, hopcount, sid, server description

Introduces a new server, directly connected to the source of this command.

SIGNON
source: user
propagation: broadcast
parameters: new nickname, new username, new visible hostname, new nickTS, new login name

Broadcasts a change of several user parameters at once.

Currently only sent after an SVSLOGIN.

SJOIN
source: server
propagation: broadcast
parameters: channelTS, simple modes, opt. mode parameters..., nicklist

Broadcasts a channel creation or bursts a channel.

The nicklist consists of users joining the channel, with status prefixes for
their status ('@+', '@', '+' or ''), for example:
'@+1JJAAAAAB +2JJAAAA4C 1JJAAAADS'. All users must be behind the source server
so it is not possible to use this message to force users to join a channel.

The interpretation depends on the channelTS and the current TS of the channel.
If either is 0, set the channel's TS to 0 and accept all modes. Otherwise, if
the incoming channelTS is greater (newer), ignore the incoming simple modes
and statuses and join and propagate just the users. If the incoming channelTS
is lower (older), wipe all modes and change the TS, notifying local users of
this but not servers (invites may be cleared). In the latter case, kick on
split riding may happen: if the key (+k) differs or the incoming simple modes
include +i, kick all local users, sending KICK messages to servers.

An SJOIN is propagated with the new TS and modes of the channel. The statuses
are propagated if and only if they were accepted.

SJOIN must be used to propagate channel creation and in netbursts. For regular
users joining channels, JOIN must be used. Pseudoservers may use SJOIN to join
a user with ops.

SNOTE
charybdis TS6
encap only
source: server
parameters: snomask letter, text

Sends the text as a server notice from the source server to opers with the
given snomask set.

SQUIT
parameters: target server, comment

Removes the target server and all servers and users behind it from the network.

If the target server is the receiving server or the local link this came from,
this is an announcement that the link is being closed.

Otherwise, if the target server is locally connected, the server should send
a WALLOPS announcing the SQUIT.

STATS
source: user
parameters: stats letter, hunted

Remote STATS request. Privileges are checked on the server executing the
actual request.

SU
encap only
encap target: *
source: services server
parameters: target user, new login name (optional)

If the new login name is not present or empty, mark the target user as not
logged in, otherwise mark the target user as logged in as the given account.

SVINFO
source: server
propagation: none
parameters: current TS version, minimum TS version, '0', current time

Verifies TS protocol compatibility and clock. If anything is not in order,
the link is dropped.

The current TS version is the highest version supported by the source server
and the minimum TS version is the lowest version supported.

The current time is sent as a TS in the usual way.

SVSLOGIN
charybdis TS6
encap only
encap target: single server
source: services server
parameters: target, new nick, new username, new visible hostname, new login name

Sent after successful SASL authentication.

The target is a UID, typically an unregistered one.

Any of the "new" parameters can be '*' to leave the corresponding field
unchanged. The new login name can be '0' to log the user out.

If the UID is registered on the network, a SIGNON with the changes will be
broadcast, otherwise the changes will be stored, to be used when registration
completes.

TB
capab: TB
source: server
propagation: broadcast
parameters: channel, topicTS, opt. topic setter, topic

Propagates a channel topic as part of a burst.

If the channel had no topic yet or the topicTS in the message is older than
the topicTS of the current topic on the channel and the topics differ, set
the topic with topicTS and topic setter, and propagate the message. Otherwise
ignore the message and do not propagate it.

If the topic setter is not present, use a server name instead.

TIME
source: user
parameters: hunted

Remote TIME request.

TMODE
source: any
parameters: channelTS, channel, cmode changes, opt. cmode parameters...

Propagates a channel mode change.

If the channelTS is greater (newer) than the current TS of the channel, drop
the message.

On input, only the limit on parameters per line restricts how many cmode
parameters can be present. Apart from this, arbitrary modes shall be
processed. Redundant modes may be dropped. For example, +n-n may be applied and
propagated as +n-n, -n or (if the channel was already -n) nothing, but not as
+n.

The parameter for mode -k (removing a key) shall be ignored.

On output, at most ten cmode parameters should be sent; if there are more,
multiple TMODE messages should be sent.

TOPIC
source: user
propagation: broadcast
parameters: channel, topic

Propagates a channel topic change. The server may verify that the source has
ops in the channel.

The topicTS shall be set to the current time and the topic setter shall be
set indicating the source user. Note that this means that the topicTS of a
topic set with TOPIC is not necessarily consistent across the network.

TRACE
source: user
1.
parameters: hunted

Performs a trace to the target, sending 200 numerics from each server passing
the message on. The target server sends a description of the target followed
by a 262 numeric.

TRACE, STATS l and STATS L are the only commands using hunt_server that use the
hunted parameter for more than just determining which server the command
should be executed on.

2.
parameters: target name, hunted

Executes a trace command on the target server. No 200 numerics are sent.
The target name is a name, not a UID, and should be on the target server.

UID
source: server
propagation: broadcast
parameters: nickname, hopcount, nickTS, umodes, username, visible hostname, IP address, UID, gecos
propagation: broadcast

Introduces a client. The client is on the source server of this command.

Nick TS rules apply.

UNDLINE
charybdis TS6
encap only
source: user
parameters: mask

Removes a D:line (IP ban checked directly after accepting connection).

The mask must be an IP address or CIDR mask.

UNKLINE
1.
encap only
source: user
parameters: user mask, host mask

Removes a K:line (ban on user@host).

2.
capab: UNKLN
source: user
parameters: target server mask, user mask, host mask

As form 1, deprecated.

UNRESV
1.
encap only
source: user
parameters: mask

Removes a RESV.

2.
capab: CLUSTER
source: user
parameters: target server mask, mask

As form 1, deprecated.

UNXLINE
1.
encap only
source: user
parameters: mask

Removes an X:line (ban on realname).

2.
capab: CLUSTER
source: user
parameters: target server mask, mask

As form 1, deprecated.

USERS
source: user
parameters: hunted

Remote USERS request.

VERSION
source: any
parameters: hunted

Remote VERSION request.

WALLOPS
1.
source: user
parameters: message
propagation: broadcast

In efnet TS6, sends a message to operators (with umode +z set). This is a
deprecated equivalent to OPERWALL.

In charybdis TS6, sends a message to local users with umode +w set (or possibly
another indication that WALLOPS messages should be sent), including non-opers.

2.
source: server
parameters: message
propagation: broadcast

Sends a message to local users with umode +w set (or possibly another
indication that WALLOPS messages should be sent).

In efnet TS6 this may include non-opers, in charybdis TS6 this may only be
sent to opers.

WHOIS
source: user
parameters: hunted, target nick

Remote WHOIS request.

XLINE
1.
encap only
source: user
parameters: duration, mask, reason

Sets an X:line (ban on realname).

2.
capab: CLUSTER
source: user
parameters: target server mask, duration, mask, reason

As form 1, deprecated.

Local only commands (charybdis 3.1):

ACCEPT
AUTHENTICATE
CAP
CHALLENGE
CHANTRACE
CLOSE
CNOTICE
CPRIVMSG
DIE
GET
HELP
ISON
LIST
MAP
MASKTRACE
MODLIST
MODLOAD
MODRELOAD
MODRESTART
MODUNLOAD
MONITOR
NAMES
OPER
POST
PUT
RESTART
SCAN
SET
TESTGECOS
TESTLINE
TESTMASK
UHELP
UNREJECT
USER
USERHOST
WEBIRC
WHO
WHOWAS