Create a Microsoft Loopback Adapter equivalent in openSUSE

I have openSUSE 13.2 32 bit installed on my machine.I would like to create a Microsoft Loopback Adapter equivalent setup in openSUSE.

In Microsoft Loopback Adapter in Windows,I can set it up and assign an IP address (e.g. 10.0.0.1) to the adapter such that I can still ping this IP even when I havent connected any network interface.This enables me to install software e.g. Oracle Database and “bind” it to this Loopback Adapter.

I dont have an ethernet connection only a Wifi connection that is on DCHP thus IP changes periodically.If I disconnect the Wifi I cannot ping its IP.Thus I need to setup a loopback adapter,assign it an IP eg 10.0.0.1 that is permanently reachable even if I am not connected to a Wifi or ethernet channel.

Kindly assist.Thanks.

A loopback device is automatically installed.

Just assign 10.0.0.1 to localhost in /etc/hosts e.g. (you can use YaST for that too)
Or (if possible) just tell your software to use the IP address 127.0.0.1, which is localhost/the loopback device.

I am not sure that I understand what you want and my knowledge of Microsoft is almost nil, but in Unix/Linux there is always a loopback net work device (when the network is started, and even without connection). The IP address is 127.0.0.1:

henk@boven:~> ping -c1 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.049 ms

--- 127.0.0.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.049/0.049/0.049/0.000 ms
henk@boven:~>

It also has a hostname:

henk@boven:~> ping -c1 localhost
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.048 ms

--- localhost ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.048/0.048/0.048/0.000 ms
henk@boven:~>

HTH

You can use any IP4 address that starts with “127” – all the 127/8 addresses are assigned to the loopback device. The 127.0.0.0/24naddresses (e.g. 127.0.0.8) may already be in use.

It is also possible to use YaST andwicked (I do not know how to do this with Network Manager) to add a new device of type dummy, which you can assign any IP address you like. This address can then be pinged internally.

In Linux, a loopback adapter is created automatically for you.

To see the properties of all your network adapters, including your loopback (typically called “lo”) run the following command

ip addr

This loopback adapter should not be assigned any LAN address, because as a loopback adapter, its interface is visible and usable only on the machine itself. A common example and use (and mistake) is for example to bind your webserver to this loopback address. When you do this, then webpages are accessible by any one or more addresses you want to assign it (typically 127.0.0.x) but not accessible from the network.

Conversely if you bind your actual ethernet adapter (might be eth0 but today more likely a name related to your NIC hardware), then it’s accessible from the network but <not> accessible using localhost or a loopback address.

Note that what you describe in your original post (and wolfi’s follow up) might work, but is typically misleading and incorrect practice because the loopback device and interface in both Windows and Linux is completely different than the network-capable interface so should not be assigned a LAN address. You can do so, but it still shouldn’t be accessible from a network.

Where I have assigned the loopback adapter a network address is when I’ve deployed a multi-homed machine configuration in a colo where there isn’t really a network behind the machine. But, because the network software demands a private network, the loopback device can be used as a pseudo device in the private network that doesn’t really exist.

HTH,
TSU