Channels & Modes

Channel types (prefix character):

• #: standard, network-wide.
• &: server-local (rarely used).
• +: modeless (rarely used).
• !: timestamped, federated (deprecated).

Joining:

C: JOIN #general
S: :alice!a@host JOIN :#general
S: :irc.example.com 332 alice #general :Topic of the channel
S: :irc.example.com 333 alice #general bob 1684000000
S: :irc.example.com 353 alice = #general :alice @bob +carol
S: :irc.example.com 366 alice #general :End of /NAMES list

353 NAMES list: prefix indicates user mode in the channel:

• @: operator (op).
• %: half-op.
• +: voice.
• ~: founder.
• &: protected.

Channel modes (MODE #channel +x style):

• +i: invite-only.
• +m: moderated (only voiced + op users speak).
• +t: topic protected (only op can change).
• +s: secret (hidden from /list).
• +k <key>: keyword (password) needed to join.
• +l <num>: user limit.
• +b <mask>: ban (e.g., +b *!*@evil.com).
• +e <mask>: ban exception.
• +I <mask>: invite exception.

User modes in channel (MODE #chan +o nick):

• +o: op.
• +v: voice.
• +h: half-op.

Op privileges: kick, change topic, change modes, set bans.

:alice!a@host MODE #general +o bob   (alice ops bob)
:alice!a@host KICK #general carol :spamming
:alice!a@host TOPIC #general :Welcome to the project

Server enforces. If non-op tries to mode/kick: 482 ERR_CHANOPRIVSNEEDED.

ChanServ (services): bot maintaining channel ownership across operator hours/network restarts. Founders register channels; ChanServ enforces ACLs.