I have a server with two different network interfaces, each with a different IP address. How can I create a socket so it'll go out a specific IP address?
I'd prefer a python example, but the question is language agnostic, so shoot away.
EDIT: Please don't give me "You can't" as an answer. I mean, it is a computer. I can do anything I like to it, for example - I can programatically disable the one interface I don't want on the fly. I'm looking for something prettier.
To assign a unique IP address to each network interface, issue the TCPIP [TCPIP] IDENTITY (TCPIP ID) command at the TCP/IP host for which you are assigning an IP address . You can issue IPv4 and IPv6 TCPIP ID commands on the same network interface.
This article describes how to change the Internet Protocol (IP) address that is assigned to a network adapter. An IP address may be assigned automatically if your network has a Dynamic Host Configuration Protocol (DHCP) server, or you can specify an IP address.
You can certainly bind a socket to a specific device.
I don't know how to do it in python, but using the berkeley socket api (in C) you need to call setsockopt()
, using the option SO_BINDTODEVICE
.
You pass in an interface descriptor, which is of type struct ifreq
. Ideally you would get the contents of the interface descriptor by using ioctl()
, and requesting SIOCGIFINDEX
- passing the name of the interface (eg. eth0) as an argument.
edit: Just did a quick search and found this documentation of the socket methods in python. setsockopt()
is amongst them.
Just a little note - what I really needed is to bind to a specific IP, and just for the sake of completeness, the solution is to bind the socket after creation. Source in python:
import socket s = socket.socket() s.bind(("127.0.0.1", 0)) s.connect(("321.12.131.432", 80))
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