/checkip Command

Syntax: /checkip <ip address>
Available Since: 2.4.0
Related Permissions: banlist

This command will check if an IP address is banned. This only checks IP bans, so even if it says that an IP is not banned, there still might be a host ban or an ID ban preventing a player from joining. Examples:

/checkip 127.0.0.1

[SERVER->] 127.0.0.1 is not banned.

/checkip 192.168.4.3

[SERVER->] 192.168.4.3 is banned:
[SERVER->] 192.168.4.3 (256.1 minutes) banned by: BobTheTank
[SERVER->]    reason: Please do not use profanity.