socket question

[Philippe C. Martin]

Hi,

I am following a few tutorial and this howto:


*************************************************************
............
What happens in the web server is a bit more complex. First, the web
server creates a "server socket".

#create an INET, STREAMing socket
serversocket = socket.socket(
socket.AF_INET, socket.SOCK_STREAM)
#bind the socket to a public host,
# and a well-known port
serversocket.bind((socket.gethostname(), 80))
#become a server socket
serversocket.listen(5)

A couple things to notice: we used socket.gethostname() so that the
socket would be visible to the outside world. If we had used s.bind(('',
80)) or s.bind(('localhost', 80)) or s.bind(('127.0.0.1', 80)) we would
still have a "server" socket, but one that was only visible within the
same machine.
............
*************************************************************

My problem is that I cannot connect to my server if the client is not on
the same PC (although I'm doing the above).
Also:
1) my server has more than one IP addresses
2) my server does not have any DNS name


.... so I want to connect to an IP address that I can ping but has no
name.


How can I do that ?

Regards,

Philippe
















--
***************************
Philippe C. Martin
SnakeCard LLC
www.snakecard.com
***************************

 

[Diez B. Roggisch]

A couple things to notice: we used socket.gethostname() so that the

socket would be visible to the outside world. If we had used s.bind(('',
80)) or s.bind(('localhost', 80)) or s.bind(('127.0.0.1', 80)) we would
still have a "server" socket, but one that was only visible within the
same machine.

This is wrong. There is a difference between passing '' and 'localhost'. The
latter binds the socket only to the ip 127.0.0.1, where '' binds it to all
available ips.

My problem is that I cannot connect to my server if the client is not on
the same PC (although I'm doing the above).
Also:
1) my server has more than one IP addresses
2) my server does not have any DNS name
... so I want to connect to an IP address that I can ping but has no
name.
How can I do that ?

Pass the ip as hostname (as string like "192.168.1.10")

 

[Philippe C. Martin]

Thanks you! that did it.

PS: the 'wrong' info I got seems to be in the official howtos
http://www.amk.ca/python/howto/sockets/

Regards,

Philippe

 

[Kartic]

Does the machine running the server code also have a firewall installed
that blocks access to the server port from outside? That is the only
possibility I can think of that prevents a non-local client from
connecting.

Also, please do a netstat -a on the machine running the server and see
the IP addresses to which the listening port is bound.

Thanks,
-Kartic

 

[Steve Horsley]

Thanks you! that did it.

That makes me wonder what socket.gethostname() was returning.
It wasn't 'localhost', was it?

Steve

 

[Philippe C. Martin]

Yes it was.

Regards,

Philippe

That makes me wonder what socket.gethostname() was returning.
It wasn't 'localhost', was it?

Steve

 

[Philippe C. Martin]

Thanks, it was a bind problem: socket.gethostname() returns 'localhost'
where '' is was was needed.

Regards,

Philippe