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_STR EAM)
#bind the socket to a public host,
# and a well-known port
serversocket.bi nd((socket.geth ostname(), 80))
#become a server socket
serversocket.li sten(5)

A couple things to notice: we used socket.gethostn ame() so that the
socket would be visible to the outside world. If we had used s.bind(('',
80)) or s.bind(('localh ost', 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
*************** ************

Jul 18 '05 #1

Subscribe Reply

1825

Diez B. Roggisch

> A couple things to notice: we used socket.gethostn ame() so that the

socket would be visible to the outside world. If we had used s.bind(('',
80)) or s.bind(('localh ost', 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")

--
Regards,

Diez B. Roggisch

Jul 18 '05 #2

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

On Mon, 07 Feb 2005 18:23:28 +0100, Diez B. Roggisch wrote:

A couple things to notice: we used socket.gethostn ame() so that the
socket would be visible to the outside world. If we had used s.bind(('',
80)) or s.bind(('localh ost', 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")

Jul 18 '05 #3

Kartic

Philippe C. Martin wrote:

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).

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

Jul 18 '05 #4

Steve Horsley

Philippe C. Martin wrote:

Thanks you! that did it.

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

Steve

Jul 18 '05 #5

Philippe C. Martin

Yes it was.

Regards,

Philippe

On Mon, 07 Feb 2005 21:30:28 +0000, Steve Horsley wrote:

Philippe C. Martin wrote:
Thanks you! that did it.

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

Steve

Jul 18 '05 #6

Philippe C. Martin

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

Regards,

Philippe

On Mon, 07 Feb 2005 11:02:13 -0800, Kartic wrote:

Philippe C. Martin wrote:
>> 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).

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

Jul 18 '05 #7

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