How to ban by IP using old Q3 rcon method

If the bad guys IP is static then there is no problem , first thing to check is if the filterban variable is on or off;
/rcon seta g_filterban 0/1 (0 = IP banning is off 1 = IP banning is on)

next we add the llama's IP
/rcon addIP 312.27.48.132 (pb_sv_banmask 312.27.48.132 has the same effect)
job done.
note:
If you use the banmask pb command the IP ban is added to your pbbans.dat just like normal bans.

if his IP is dynamic you need to do a little more work .. first stage is to collect some IP addresses he connects with .. it will look something like this;
312.27.48.120
312.27.48.38
312.27.32.12
312.27.32.89
312.27.48.10
312.27.48.91
312.27.32.140
notice that the common numbers are 312.27.48 and 312.27.32 ... what we do now is ban all IP's within that range like this

/rcon addIP 312.27.48
/rcon addIP 312.27.32

this will filter all IP's in the range of 312.27.48.0 through 312.27.48.255 and 312.27.32.0 through 312.27.32.255 this effectively bans your lamer without banning a whole IP range that affects a lot of innocent people

if we just ban the whole IP range
/rcon addIP 312.27
this bans all IP's from 312.27.48.0 through 312.27.255.255
( we get 65,000 people by multiplying 255x255)

your call , its your server, ban 65,000 in one stroke or do a little work and ban a llama

All the above IP's are fictitious and for demo purposes only but if you are prepared to put in the effort an effective ban can be applied to anyone regardless of wether the IP is static or dynamic