Virtual network interface in Mac OS X

Hans_Doggen_9504 0
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I know that you can make a virtual network interface in Windows (see here), and in Linux it is also pretty easy with ip-aliases, but does something similar exist for Mac OS X? I've been looking for loopback adapters, virtual interfaces and couldn't find a good solution.

You can create a new interface in the networking panel, based on an existing interface, but it will not act as a real fully functional interface (if the original interface is inactive, then the derived one is also inactive).

This scenario is needed when working in a completely disconnected situation. Even then, it makes sense to have networking capabilities when running servers in a VMWare installation. Those virtual machines can be reached by their IP address, but not by their DNS name, even if I run a DNS server in one of those virtual machines. By configuring an interface to use the virtual DNS server, I thought I could test some DNS scenario's. Unfortunately, no interface is resolving DNS names if none of them are inactive...

dns ip macos networking
12 Answers

The loopback adapter is always up.

ifconfig lo0 alias 172.16.123.1 will add an alias IP 172.16.123.1 to the loopback adapter

ifconfig lo0 -alias 172.16.123.1 will remove it

Admin1

if you are on a dev environment and want access some service already running on localhost/host machine. in docker for mac you have another option.use docker.for.mac.localhost instead of localhost in docker container. docker.for.mac.host.internal should be used instead of docker.for.mac.localhost from Docker Community Edition 17.12.0-ce-mac46 2018-01-09. this allows you to connect to service running on your on mac from within a docker container.please refer below links

understanding the docker.for.mac.localhost behavior

release notes

user_34928660

What do you mean by

"but it will not act as a real fully functional interface (if the original interface is inactive, then the derived one is also inactive"

?

I can make a new interface, base it on an already existing one, then disable the existing one and the new one still works. Making a second interface does however not create a real interface (when you check with ifconfig), it will just assign a second IP to the already existing one (however, this one can be DHCP while the first one is hard coded for example).

So did I understand you right, that you want to create an interface, not bound to any real interface? How would this interface then be used? E.g. if you disconnect all WLAN and pull all network cables, where would this interface send traffic to, if you send traffic to it? Maybe your question is a bit unclear, it might help a lot if rephrase it, so it's clear what you are actually trying to do with this "virtual interface" once you have it.

As you mentioned "alias IP" in your question, this would mean an alias interface. But an alias interface is always bound to a real interface. The difference is in Linux such an interface really IS an interface (e.g. an alias interface for eth0 could be eth1), while on Mac, no real interface is created, instead a virtual interface is created, that can configured and used independently, but it is still the same interface physically and thus no new named interface is generated (you just have two interfaces, that are both in fact en0, but both can be enabled/disabled and configured independently).

user_158090

Go to Network Preferences.

At the bottom of the list of network adapters, click the + icons

Select the existing interface that you want to arp (say Ethernet 1), and give the Service Name that you want for the new port (say Ethernet 1.1) then press create.

Now you have the new virtual interface in the gui and can manage IP addresses etc it in the normal way.

ifconfig -a will confirm that you have multiple IPs on the interface, and these will still be there when you reboot.

Its a Mac. Don't fight it, do it the easy way.

user_5640530

ifconfig interfacename create will create a virtual interface,

Brian_Mitchell_137160
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