fping not working if ipv6 is disabled

[grufo]

If you disable ipv6 with the kernel boot option "ipv6.disable=1" then fping does not work in ubuntu 18.04.

root@server:/tmp# fping -4 -a -g 192.168.100.0/24
(null): can't create raw socket (must run as root?) : Address family not supported by protocol

If you enable ipv6 fping is fine again!

There seems to be a fix on github... (since july 2018!)
https://github.com/schweikert/fping/issues/118

Installed fping version is 4.0-6, with disabled ipv6 you can't even call "fping -v"!

[Axel Beckert (xtaran)]

> There seems to be a fix on github... (since july 2018!)

Yes, and according to the fping version you mentioned, you're running Ubuntu 18.04 Bionic from _April_ 2018. So that Ubuntu release was released before the bug was fixed upstream.

Upgrading to a more recent version of Ubuntu will fix this as this is fixed in package version 4.1-1 and all later and supported versions of Ubuntu do have at least 4.2-1.

So this bug is more or less fixed—also in Ubuntu—from the general point of view. It's just not fixed in Ubuntu 18.04 Bionic. But since this neither a severe nor a security issue, chances that the fix gets backported to 18.04 are not very high.

[Axel Beckert (xtaran)]

Closing as fix-released since the fix should now be also in the most recent Ubuntu LTS version (i.e. Ubuntu 20.04 LTS).