if youre running it online or on LAN... why use loopback 
try this.. disable youre loopback thing..
go to your HOST (located on C:\WINDOWS\system32\drivers\etc)
open it with notepad
put your SERVER LAN IP and your Global IP
example:
SERVER LAN IP : 192.168.0.100
Global IP : 123.23.123.23
Code:
# Copyright (c) 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
127.0.0.1 localhost
192.168.0.100 123.23.123.123
if youre using NO-IP you can use it also
example:
SERVER LAN IP : 192.168.0.100
NO-IP DNS : evo.zapto.org
Code:
# Copyright (c) 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
127.0.0.1 localhost
192.168.0.100 evo.zapto.org
if your neighbor is connecting to you thru LAN
edit his HOST also like you did on your host..
NOTE: use the SERVER LAN IP not his PC LAN IP
hope the helps.. gudluck