Users & Nicknames

User Identity

Each connected client is identified by a hostmask in the format:

nickname!ident@hostname

For example: Alice!alice@user.isp.com

Component	Description
nickname	The user’s current nick (up to 30 chars by default)
ident	The username/ident (up to 10 chars, from USER command or ident service)
hostname	The user’s resolved hostname (or IP if DNS fails)

Nicknames

Rules

• Maximum length: 30 characters (configurable via max_nick_length)
• Must not already be in use (case-insensitive comparison)
• Case mapping follows the server’s configured case_mapping (default: rfc1459)

Case Mapping

The server normalizes nicknames internally using case mapping. This determines which characters are considered equivalent:

Mode	Behavior
rfc1459	`
strict_rfc1459	Only A-Z are uppercase of a-z; {}| are not equivalent
ascii	Only A-Z and a-z are treated as case-equivalent

Note

Changing the case mapping after the server has started and users/channels exist may lead to unexpected behavior. Set this before first use.

Nickname Changes

Users can change their nick at any time with /nick NewNick. The change is broadcast to all channels the user is in.

Reserved Nicknames

Certain operations temporarily reserve a nickname to prevent someone else from using it:

• After NickServ RECOVER: the recovered nick is reserved for recover_reservation_duration seconds (default: 60s)
• After NickServ REGAIN: the regained nick is reserved for regain_reservation_duration seconds (default: 60s)

During the reservation period, no one (not even the original user) can claim the nick.

Ident Lookup

When a user connects, the server performs an ident query (RFC 1413) if ident_service.enabled = true (the default):

1. The server connects to the client’s port 113 (identd)
2. If the client responds, the returned username replaces the USER-provided ident
3. If no response within ident_service.timeout (default: 2000ms), the USER-provided ident is used with a ~ prefix

If no ident response is received, the ident typically appears as ~username in the user’s mask.

Hostname Resolution

Simultaneously with the ident check, the server performs a reverse DNS lookup:

• If a hostname is resolved, it is used instead of the raw IP address
• If no hostname is found, the IP address is used (formatted appropriately for IPv4/IPv6)

Hostname Cloaking

When hostname cloaking is enabled (cloaking.enabled = true), each user gets a cloaked hostname generated from their real hostname using an HMAC-based algorithm with the configured cloak_keys.

• Users enable cloaking by setting +x (Cloaked Hostname) mode
• The cloaked hostname uses the format: prefix-HASH.domain-parts
• Example: elixir-A3F2B1C8.isp.com (with cloak_prefix: "elixir", cloak_domain_parts: 2)

If cloak_on_connect: true, users automatically get +x upon registration.

If cloak_allow_disable: false, users cannot remove their +x mode.

See Hostname Cloaking for full details.

User Modes

Users can have the following modes set on them:

Mode	Name	Who sets it	Description
+B	Bot	User	Marks the user as a bot
+g	Caller ID	User	Blocks PRIVMSGs from non-accepted users
+H	Hide Operator	Operator only	Hides IRC op status in WHOIS
+i	Invisible	User	Hides from WHO/WHOIS for non-shared channels
+o	IRC Operator	Server only	Elevated server privileges
+r	Registered	Server only	Identified with NickServ or SASL
+R	Registered Only	User	Only registered users can PRIVMSG you
+s	Server Notices	Operator only	Receive server notice messages
+w	Wallops	User	Receive WALLOPS messages
+x	Cloaked	User	Use cloaked hostname
+Z	Secure	Server only	Connected via SSL/TLS

See User Modes for complete details.

User State

A user’s state includes:

• nick — current nickname
• ident — username
• hostname — resolved hostname (or IP)
• cloaked_hostname — HMAC-based cloaked hostname
• realname — real name (GECOS), up to 50 chars
• modes — list of active user modes
• away_message — away message, if set
• identified_as — NickServ account the user is identified to
• sasl_authenticated — whether authentication happened via SASL
• capabilities — negotiated IRCv3 capabilities
• transport — :tcp, :tls, :ws, or :wss
• ip_address — real IP address
• webirc_* — WebIRC gateway info (if connection came through WebIRC)

Inactivity Timeout

Users who send no messages for inactivity_timeout_ms (default: 180,000ms = 3 minutes) are disconnected with an inactivity timeout.

Regular IRC messages (including PINGs sent by the client) reset the inactivity timer.

AWAY Status

Users can set an away message with /away message. This:

• Sets the away_message field
• Broadcasts an AWAY notification to users who have the AWAY-NOTIFY capability enabled
• Is shown in /whois responses
• Results in an auto-reply when users PRIVMSG them

Clear away status with /away (no message).

WHOWAS History

When a user disconnects, their information is stored in the HistoricalUsers table for a limited time, allowing other users to retrieve it with WHOWAS.