- A user MAY specify a nick when joining the channel. Channels MAY have mandatory nicks, which is default behavior. Therefore it is will generally be necessary to include a nick when joining an channel. If nick is missing on a channel where nick is mandatory, the join MUST be rejected. Other error cases are dealt with below with the nick management commands. Where a nick is specified, the join will only complete if the nick is accepted. The nick used MUST be reported back in the join result. + A user MAY specify a nick when joining the channel. Channels MAY have mandatory nicks, which is default behavior. Therefore it will generally be necessary to include a nick when joining an channel. If nick is missing on a channel where nick is mandatory, the join MUST be rejected. Other error cases are dealt with below with the nick management commands. Where a nick is specified, the join will only complete if the nick is accepted. The nick used MUST be reported back in the join result.