Channel Modes

Access levels – These are the modes that grant a certain ‘level’ to a user.

Set with /mode #yourchan +/-<MODE> <USER>

Example: /mode #help +v William

Channel mode Description Restrictions
v Voice. This makes the user able to speak in +m/+M channels. User can also still speak if banned. May be set by +hoaq users
h Half-Op. Gives some of the usual channel operator rights, but not all. They are basically a light version of channel ops. May be set by +oaq users
o Channel Op. This is the channel operator privilege everyone knows about, allows the user to do almost all administrative tasks in a channel such as /KICK, /MODE, etc.. May be set by +oaq users
a Channel Admin. A level above channel ops but with no special extra privileges except for one: people below chanadmin (so +h/+o) cannot KICK +a people. May be set by +q users
q Channel Owner. The highest level. Channel owners can’t be kicked by any level below. Usually there’s only one person with +q and the mode is set by services. Normal users can’t set this

Note that often Services are used to manage +vhoaq lists in so called “access lists” or AOP/HOP/etc.

List modes – These are so called ‘list modes’.

Set with /mode #yourchan +/-<MODE> <MASK>

Example: /mode #help +b *William@*.chatcorner.live

Channel mode Description Restrictions
b Ban. Prevents a user from joining the channel. Requires +h or higher
e Ban exception. When a user is banned (due to +b) and they are on this +e list then they may still join the channel. Requires +h or higher
I Invite exception. When the channel is +i (invite only) then people on this list may still join the channel. Requires +h or higher

All these modes take a nick!user@host parameter, like: +b *!*@*.isp.com. See also Extended bans for other syntaxes (eg: +e ~c:@#channel).

Channel settings – These are channel modes that configure channel settings.

Set with /mode #yourchan +/-<MODE>

Example: /mode #help +cC

Channel mode Description Restrictions
c No color allowed in the channel. Will block ANSI and mIRC color codes. Requires +o or higher
C No CTCP’s allowed in the channel. Requires +o or higher
D Delays someone’s JOIN message until that person speaks. Chanops and higher, opers and ulines/services are exempt. Requires +o or higher
d When unsetting +D, Unreal needs to process all remaining delayed users (i.e. invisible in the channel to regular users) to make them JOIN. +d is an intermediate/temporary mode to facilitate this and will be unset once all users are properly “joined”. Set by server
f Flood protection. This is a highly advanced feature, see Anti-flood features#Channel_mode_f Requires +o or higher
G Filter out bad words (Chat Corner maintains a listing) Requires +o or higher
i Invite only. Requires people to be /INVITE’d to the channel or be on the +I (Invite Exceptions) list (for that latter, see the List modes section above) Requires +o or higher
k Require users to specify a channel key in order to join (/JOIN #chan key). Example: +k secret Requires +h or higher
K /KNOCK command is not allowed. Requires +o or higher
L Channel link. If the +l user limit (see below) is reached then users will automatically be redirected to this channel. Example: +L #something Requires +h or higher
l Limit the amount of users that may be in the channel. If the limit is reached then any new JOIN’s are rejected (see also +L above). Requires +o or higher
m Moderated channel. Only people with +v or higher (+vhoaq) may speak. Requires +h or higher
M Must be authenticated to services or have +v or higher to speak. Requires +o or higher
N No nick-changes permitted. Normally not set, only during a a nick-flood flood attack. Requires +o or higher
n No external messages. If you don’t set +n then users outside the channel may still send messages to it. Thus, almost everyone will set their channel +n. Requires +h or higher
O IRC Operator only channel IRCOp-only
P Permanent channel. After all users leave a channel it is normally destroyed. If you set +P then this won’t happen and all settings are preserved. IRCOp-only
p Private channel (Not visible in /msg chanserv list) Requires +o or higher
Q No /KICK allowed. Can be used to force all chanops to use Services for kicking. Unusual, but possible. Requires +o or higher
R Only registered users may join the channel. Registered users are users authenticated to NickServ. Requires +o or higher
r Channel is registered via ChanServ Set by services
s Secret channel. The channel won’t show up in /LIST and won’t show up in /WHOIS (unless you are in the same channel or an IRCOp) Requires +o or higher
S Strip color codes. This removes any mIRC or ANSI color codes by converting it to regular text. Requires +o or higher
T Channel notices are not permitted (/NOTICE #chan hi!). On many clients a beeping sound will happen on notices, hence why this mode is sometimes set. Requires +o or higher
t Restricts /TOPIC to +h or higher. Without +t anyone in the channel may set the topic. Most channels are +t. Requires +h or higher
V /INVITE is not permitted. Requires +o or higher
z Only clients which are connected through SSL/TLS may join the channel Requires +o or higher
Z Indicates that only people who are using SSL/TLS are on the channel. This channel mode is (only) set by the server when the channel is also +z and everyone on the channel is connected via SSL. Set by server
*This information taken from https://www.unrealircd.org/docs/Channel_modes