requirements(RFC1573, interface MIB). This change for 4.4BSD was
first introduced in if_ethersubr.c:1.17->1.18.
BTW, iflastchange on all of IFs are inconsistent. e.g.
ether, tun: update
fddi, tokenring, ppp: not update
I'll make patch later.
Obtained from: KAME
MFC after: 2 weeks