Clients on server:
 #  nick             authid               userid   imm  res  access
 2  Basoner          STEAM_0:0:1575896814 596      No     No     z
 4  (5)            VALVE_0:4:1810468868 607      No     No     z
 5  (2)            VALVE_0:4:1810468868 599      No     No     z
 6  (3)            VALVE_0:4:1810468868 600      No     No     z
 7  (4)            VALVE_0:4:1810468868 601      No     No     z
 8  noob             VALVE_0:4:1769836151 618      No     Yes    bcdeju
10  (6)            VALVE_0:4:1810468868 608      No     No     z
11  (7)            VALVE_0:4:1810468868 609      No     No     z
12  (8)            VALVE_0:4:1810468868 610      No     No     z
13  kokata           VALVE_0:4:1095240434 611      No     No     z
14  (9)            VALVE_0:4:1810468868 612      No     No     z
15  afdgadf          STEAM_0:0:1278624167 619      No     Yes    bcdeju
16  (10)           VALVE_0:4:1810468868 614      No     No     z
17  (11)           VALVE_0:4:1810468868 615      No     No     z
18  (12)           VALVE_0:4:1810468868 616      No     No     z          VALVE_0:4:1810468868 616      No     No     z

(2) killed self with worldspawn
(9) killed self with worldspawn
kokata killed (3) with tau cannon
(5) killed self with worldspawn
Player killed  with tau cannon
(4) killed self with worldspawn
(11) killed self with worldspawn
kokata killed (6) with tau cannon
(10) killed self with worldspawn
noob killed Basoner with shotgun
kokata killed (8) with tau cannon
(1) killed self with worldspawn
(2) killed self with worldspawn
kokata killed (9) with tau cannon
noob killed Basoner with crossbow
(7) killed self with worldspawn
(5) killed self with worldspawn
(3) killed self with worldspawn
 killed noob with grenade
(10) killed self with worldspawn
(11) killed self with worldspawn

03/14/2015 - 23:29:04: [ Connecting... ][ Nickname: ^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ] 03/14/2015 - 23:29:15: [ Connecting... ][ Nickname: (1)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (1)^2: timeleft 03/14/2015 - 23:29:23: [ Connecting... ][ Nickname: (2)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (2)^2: timeleft 03/14/2015 - 23:29:31: [ Connecting... ][ Nickname: (3)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
[DPROTO]: Client "besame" timed out for 36.0485secL 03/14/2015 - 23:29:39: [ Connecting... ][ Nickname: (4)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (4)^2: timeleft
L 03/14/2015 - 23:33:06: [ Connecting... ][ Nickname: (5)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (5)^2: timeleft
L 03/14/2015 - 23:33:13: [ Connecting... ][ Nickname: (6)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (6)^2: timeleft
L 03/14/2015 - 23:33:19: [ Connecting... ][ Nickname: (7)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (7)^2: timeleft
L 03/14/2015 - 23:33:28: [ Connecting... ][ Nickname: (8)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (8)^2: timeleft
L 03/14/2015 - 23:34:23: [ Connecting... ][ Nickname: (10)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (10)^2: timeleft
L 03/14/2015 - 23:34:32: [ Connecting... ][ Nickname: (11)^2 ][ IP Address: 176.194.143.126 ][ SteamID: VALVE_0:4:1810468868 ]
(TEAM) (11)^2: timeleft

#include <amxmodx>
#include <amxmisc>

#define PLUGIN   "One IP"
#define AUTHOR   "LetiLetiLepestok"
#define VERSION   "0.1"

public plugin_init()
{
   register_plugin(PLUGIN, VERSION, AUTHOR)
}


public client_connect(id)
{
   static _players[32], _num, new_player_ip[16], player_ip[16]
   new count
   
   get_user_ip(id, new_player_ip, 15, 1) 
   
   get_players(_players, _num)
   
   for (new _i=0; _i<_num; _i++)
   {
      get_user_ip(_players[_i], player_ip, 15, 1)
      
      if(equal(new_player_ip, player_ip))
      {
         if(count > 1)
         {
            server_cmd("kick #%d Another player with your IP is playing here...", get_user_userid(id))
            break
         }
         count++
      }
   }
}