socket security

[Alastair Nicol]

Hi,
  I've been enjoying the wonders of socket programming with Python. I have 
read a lot of information on the subject, but still have a few unanswered 
questions which is why, out of desperation, i'm asking here. 

1) Can only hosts which can see the interface your program is bound to 
communicate with your program. In the "normal" case if you bind to 
127.0.0.1 for example ONLY your machine can see that interface. Other 
machines cannot connect to it. Is this a safe / secure assumtion? (not just 
for localhost)

2) Also when a client connects to a socket the server gets the IP address 
of the client. Is this the "real" ip number? Ive heard you can spoof IP 
numbers so what hoops are needed to validate that the client is really that 
client.

openSSL is an option i would like to use, but for reasons to numerious to 
list here, i cant.


Thanks, Alastair Nicol