unable to get default ip address for interface connected back to back

chakka.lokesh · 08-11-2014, 08:28 AM

I am in need of running a server and client in same computer on two different interfaces connected back to back using raw ethernet sockets.

one interface is normal one fixed inside and another interface is usb based external NIC.

"cat /etc/network/interfaces" is as follows:

Code:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.100

auto eth1
iface eth1 inet static
address 192.168.1.200

if i keep the above configuration, networking is not getting enabled at all.
instead if I comment out last three lines (for eth1 which is external usb nic), I am seeing eth1 is showing up but not acquiring any ip address, also I am not seeing packets are going out on the wire.

Can some one plz help me in fixing the issue.

My requirements are as follows:

1. I need to connect both the interfaces back to back, boot the computer.
2. Both the interfaces should come up with ip address.
3. I should be able to run client on one interface and server on another interface.

Can some one please help me in configuring my computer so that i can achieve all the above three.

schneidz · 08-11-2014, 08:35 AM

is this related:
http://www.linuxquestions.org/questi...6/#post3804866

suicidaleggroll · 08-11-2014, 10:04 AM

Is there a reason you can't just use the loopback interface to communicate between your server and client? Server listens for connections on port, say, 9000, and the client connects to 127.0.0.1:9000 to open the connection. I don't see why you need two NICs for this, unless there's something I'm missing.

solarisguy · 08-24-2014, 12:12 AM

If the client and server need to be running on the same system, you can also share the same physical interface and use a sub interface/alias.

Code:

ifconfig eth0 192.168.1.100/24
ifconfig eth0:1 192.168.1.200/24

Or to create a persistent subinterface, use the following in /etc/network/interfaces:

Code:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
address 192.168.1.100

auto eth0:1
iface eth0:1 inet static
address 192.168.1.200

chakka.lokesh · 08-24-2014, 11:50 PM

I am in need of running server and client on two different interfaces in the same machine only.
Because I will be connecting some network components like routers / switches etc to these interfaces.

chakka.lokesh · 08-25-2014, 03:02 AM

in this setup, I am able to open the raw sockets and also able to bind them to the interface.
But write function is failing with error ENETDOWN i.e., "Network is down"