The nwfilter code uses ETH_ALEN, which isn't defined on MacOS X. This is a simple workaround, to add it when missing. --- src/nwfilter/nwfilter_learnipaddr.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/src/nwfilter/nwfilter_learnipaddr.c b/src/nwfilter/nwfilter_learnipaddr.c index 7c94fc2..554422b 100644 --- a/src/nwfilter/nwfilter_learnipaddr.c +++ b/src/nwfilter/nwfilter_learnipaddr.c @@ -38,6 +38,11 @@ #include <net/if_arp.h> #include <intprops.h> +// Add Linux define missing from OSX +#ifndef ETH_ALEN +#define ETH_ALEN 6 /* Octets in one ethernet addr */ +#endif + #include "internal.h" #include "buf.h" -- 1.7.2.3