9

I need one more loopback interface in my OpenBSD 6.1, with the IP address 127.0.0.2.

I can create it by hand with the command:

ifconfig lo1 127.0.0.2

And to have it at boot time, I just inserted that command into /etc/rc.local.

I have researched for a more standard way to do that, was not successful.

Having it in /etc/rc.local also means I only have that interface late in the boot process.

How may I configure it in a cleaner "OpenBSD" way?

11

As hinted at in lo(4), you may create /etc/hostname.lo1:

inet 127.0.0.2 255.0.0.0

This will create the lo1 interface when the boot process runs /etc/netstart. With that file in place, you may also set up the interface without rebooting through

$ doas sh /etc/netstart lo1

The interface is reported as

lo1: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 32768
        index 4 priority 0 llprio 3
        groups: lo
        inet 127.0.0.2 netmask 0xff000000

by ifconfig.

For further info, see hostname.if(5), netstart(8) and ifconfig(8).

  • 2
    Thanks for all the help, I am getting my feet wet in OpenBSD in a personal netbook as a pilot/(re)introduction to the system. – Rui F Ribeiro Jun 14 '17 at 8:36
0

Unless you have a reason for this to be an additional network interface, note that you do not have to have a second interface just in order to have a second IP address in 127.0.0.0/8. You can add the second IP address to the existing loopback interface:

# echo >> /etc/hostname.lo0 inet alias 127.0.0.2 255.0.0.0
# 

Remember if you do this that you need the -A option to ifconfig now. It's a slightly misleading option. It does not target aliases per se. It simply stops ifconfig from displaying only the first IP version 4 address that it finds, which is what it actually does in lieu of finding out which IP addresses are aliases.

  • I defined a interface to give it to some particular software at the time. Switched back to freebsd. – Rui F Ribeiro Mar 23 at 19:21

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