iputils has wrong check for kernel features, which leads to the warning from the subject when user is pinging host via the network without proper routing for that. The problem is someway described on the debian bz: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=709052 I'd also note, that I can reproduce it every time by either unplugging Ethernet from the router or: > ping 8.8.8.8 -I vpn (where vpn is (SUDDENLY) tun/tap VPN interface without internet access, managed by tinc-1.1pre11 in switch mode).
See also https://github.com/iputils/iputils/commit/5bb0f0a8b0ed6f111a329c0d6911dfa516ab1d42
Can confirm the same error on gentoo-sources-4.0.1 and iputils-20121221-r1
(In reply to Felix Janda from comment #1) i glanced through that commit and i'm not convinced it's entirely correct. it isn't only deleting the warning message, but also adding socket options and detecting resulting errors.
Created attachment 405768 [details, diff] Patch to remove bogus check required for < 2.4.9 kernels Attached a proposed patch to fix this issue. It clears up the warning on my side without any new issues appearing on my side. Based on https://github.com/iputils/iputils/commit/5bb0f0a8b0ed6f111a329c0d6911dfa516ab1d42?diff=unified